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boinc/client/cpu_sched.C

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// Berkeley Open Infrastructure for Network Computing
// http://boinc.berkeley.edu
// Copyright (C) 2005 University of California
//
// This is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation;
// either version 2.1 of the License, or (at your option) any later version.
//
// This software is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// To view the GNU Lesser General Public License visit
// http://www.gnu.org/copyleft/lesser.html
// or write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
// CPU scheduling logic.
//
// Terminology:
//
// Episode
// The execution of a task is divided into "episodes".
// An episode starts then the application is executed,
// and ends when it exits or dies
// (e.g., because it's preempted and not left in memory,
// or the user quits BOINC, or the host is turned off).
// A task may checkpoint now and then.
// Each episode begins with the state of the last checkpoint.
//
// Debt interval
// The interval between consecutive executions of adjust_debts()
//
// Run interval
// If an app is running (not suspended), the interval
// during which it's been running.
#ifdef _WIN32
#include "boinc_win.h"
#endif
#ifdef SIM
#include "sim.h"
#else
#include "client_state.h"
#endif
#include "client_msgs.h"
#include "str_util.h"
#include "util.h"
#include "error_numbers.h"
#include "log_flags.h"
using std::vector;
#define MAX_STD (86400)
// maximum short-term debt
#define CPU_PESSIMISM_FACTOR 0.9
// assume actual CPU utilization will be this multiple
// of what we've actually measured recently
#define DEADLINE_CUSHION 0
// try to finish jobs this much in advance of their deadline
static bool more_preemptable(ACTIVE_TASK* t0, ACTIVE_TASK* t1) {
// returning true means t1 is more preemptable than t0,
// the "largest" result is at the front of a heap,
// and we want the best replacement at the front,
//
if (t0->result->project->deadlines_missed && !t1->result->project->deadlines_missed) return false;
if (!t0->result->project->deadlines_missed && t1->result->project->deadlines_missed) return true;
if (t0->result->project->deadlines_missed && t1->result->project->deadlines_missed) {
if (t0->result->report_deadline > t1->result->report_deadline) return true;
return false;
} else {
double t0_episode_time = gstate.now - t0->run_interval_start_wall_time;
double t1_episode_time = gstate.now - t1->run_interval_start_wall_time;
if (t0_episode_time < t1_episode_time) return false;
if (t0_episode_time > t1_episode_time) return true;
if (t0->result->report_deadline > t1->result->report_deadline) return true;
return false;
}
}
// Choose a "best" runnable result for each project
//
// Values are returned in project->next_runnable_result
// (skip projects for which this is already non-NULL)
//
// Don't choose results with already_selected == true;
// mark chosen results as already_selected.
//
// The preference order:
// 1. results with active tasks that are running
// 2. results with active tasks that are preempted (but have a process)
// 3. results with active tasks that have no process
// 4. results with no active task
//
// TODO: this is called in a loop over NCPUs, which is silly.
// Should call it once, and have it make an ordered list per project.
//
void CLIENT_STATE::assign_results_to_projects() {
unsigned int i;
RESULT* rp;
PROJECT* project;
// scan results with an ACTIVE_TASK
//
for (i=0; i<active_tasks.active_tasks.size(); i++) {
ACTIVE_TASK *atp = active_tasks.active_tasks[i];
if (!atp->runnable()) continue;
rp = atp->result;
if (rp->already_selected) continue;
if (!rp->runnable()) continue;
project = rp->project;
if (!project->next_runnable_result) {
project->next_runnable_result = rp;
continue;
}
// see if this task is "better" than the one currently
// selected for this project
//
ACTIVE_TASK *next_atp = lookup_active_task_by_result(
project->next_runnable_result
);
if ((next_atp->task_state() == PROCESS_UNINITIALIZED && atp->process_exists())
|| (next_atp->scheduler_state == CPU_SCHED_PREEMPTED
&& atp->scheduler_state == CPU_SCHED_SCHEDULED)
) {
project->next_runnable_result = atp->result;
}
}
// Now consider results that don't have an active task
//
for (i=0; i<results.size(); i++) {
rp = results[i];
if (rp->already_selected) continue;
if (lookup_active_task_by_result(rp)) continue;
if (!rp->runnable()) continue;
project = rp->project;
if (project->next_runnable_result) continue;
project->next_runnable_result = rp;
}
// mark selected results, so CPU scheduler won't try to consider
// a result more than once
//
for (i=0; i<projects.size(); i++) {
project = projects[i];
if (project->next_runnable_result) {
project->next_runnable_result->already_selected = true;
}
}
}
// Among projects with a "next runnable result",
// find the project P with the greatest anticipated debt,
// and return its next runnable result
//
RESULT* CLIENT_STATE::largest_debt_project_best_result() {
PROJECT *best_project = NULL;
double best_debt = -MAX_STD;
bool first = true;
unsigned int i;
for (i=0; i<projects.size(); i++) {
PROJECT* p = projects[i];
if (!p->next_runnable_result) continue;
if (p->non_cpu_intensive) continue;
if (first || p->anticipated_debt > best_debt) {
first = false;
best_project = p;
best_debt = p->anticipated_debt;
}
}
if (!best_project) return NULL;
if (log_flags.cpu_sched_debug) {
msg_printf(best_project, MSG_INFO,
"[cpu_sched_debug] highest debt: %f %s",
best_project->anticipated_debt,
best_project->next_runnable_result->name
);
}
RESULT* rp = best_project->next_runnable_result;
best_project->next_runnable_result = 0;
return rp;
}
// Return earliest-deadline result from a project with deadlines_missed>0
//
RESULT* CLIENT_STATE::earliest_deadline_result() {
RESULT *best_result = NULL;
ACTIVE_TASK* best_atp = NULL;
unsigned int i;
for (i=0; i<results.size(); i++) {
RESULT* rp = results[i];
if (!rp->runnable()) continue;
if (rp->project->non_cpu_intensive) continue;
if (rp->already_selected) continue;
if (!rp->project->deadlines_missed) continue;
if (!best_result || rp->report_deadline<best_result->report_deadline) {
best_result = rp;
best_atp = lookup_active_task_by_result(rp);
continue;
}
if (rp->report_deadline > best_result->report_deadline) {
continue;
}
// If there's a tie, pick the job with the least remaining CPU time
// (but don't pick an unstarted job over one that's started)
//
ACTIVE_TASK* atp = lookup_active_task_by_result(rp);
if (best_atp && !atp) continue;
if (rp->estimated_cpu_time_remaining(false)
< best_result->estimated_cpu_time_remaining(false)
) {
best_result = rp;
best_atp = atp;
}
}
if (!best_result) return NULL;
if (log_flags.cpu_sched_debug) {
msg_printf(best_result->project, MSG_INFO,
"[cpu_sched_debug] earliest deadline: %f %s",
best_result->report_deadline, best_result->name
);
}
return best_result;
}
void CLIENT_STATE::reset_debt_accounting() {
unsigned int i;
for (i=0; i<projects.size(); i++) {
PROJECT* p = projects[i];
p->wall_cpu_time_this_debt_interval = 0.0;
}
for (i = 0; i < active_tasks.active_tasks.size(); ++i) {
ACTIVE_TASK* atp = active_tasks.active_tasks[i];
atp->debt_interval_start_cpu_time = atp->current_cpu_time;
}
total_wall_cpu_time_this_debt_interval = 0.0;
total_cpu_time_this_debt_interval = 0.0;
debt_interval_start = now;
}
// adjust project debts (short, long-term)
//
void CLIENT_STATE::adjust_debts() {
unsigned int i;
double total_long_term_debt = 0;
double total_short_term_debt = 0;
double prrs, rrs;
int nprojects=0, nrprojects=0;
PROJECT *p;
double share_frac;
double wall_cpu_time = now - debt_interval_start;
if (wall_cpu_time < 1) {
return;
}
// if the elapsed time is more than the scheduling period,
// it must be because the host was suspended for a long time.
// Currently we don't have a way to estimate how long this was for,
// so ignore the last period and reset counters.
//
if (wall_cpu_time > global_prefs.cpu_scheduling_period()*2) {
if (log_flags.debt_debug) {
msg_printf(NULL, MSG_INFO,
"[debt_debug] adjust_debt: elapsed time (%d) longer than sched period (%d). Ignoring this period.",
(int)wall_cpu_time, (int)global_prefs.cpu_scheduling_period()
);
}
reset_debt_accounting();
return;
}
// Total up total and per-project "wall CPU" since last CPU reschedule.
// "Wall CPU" is the wall time during which a task was
// runnable (at the OS level).
//
// We use wall CPU for debt calculation
// (instead of reported actual CPU) for two reasons:
// 1) the process might have paged a lot, so the actual CPU
// may be a lot less than wall CPU
// 2) BOINC relies on apps to report their CPU time.
// Sometimes there are bugs and apps report zero CPU.
// It's safer not to trust them.
//
for (i=0; i<active_tasks.active_tasks.size(); i++) {
ACTIVE_TASK* atp = active_tasks.active_tasks[i];
if (atp->scheduler_state != CPU_SCHED_SCHEDULED) continue;
if (atp->wup->project->non_cpu_intensive) continue;
atp->result->project->wall_cpu_time_this_debt_interval += wall_cpu_time;
total_wall_cpu_time_this_debt_interval += wall_cpu_time;
total_cpu_time_this_debt_interval += atp->current_cpu_time - atp->debt_interval_start_cpu_time;
}
time_stats.update_cpu_efficiency(
total_wall_cpu_time_this_debt_interval, total_cpu_time_this_debt_interval
);
rrs = runnable_resource_share();
prrs = potentially_runnable_resource_share();
for (i=0; i<projects.size(); i++) {
p = projects[i];
// potentially_runnable() can be false right after a result completes,
// but we still need to update its LTD.
// In this case its wall_cpu_time_this_debt_interval will be nonzero.
//
if (!(p->potentially_runnable()) && p->wall_cpu_time_this_debt_interval) {
prrs += p->resource_share;
}
}
for (i=0; i<projects.size(); i++) {
p = projects[i];
if (p->non_cpu_intensive) continue;
nprojects++;
// adjust long-term debts
//
if (p->potentially_runnable() || p->wall_cpu_time_this_debt_interval) {
share_frac = p->resource_share/prrs;
p->long_term_debt += share_frac*total_wall_cpu_time_this_debt_interval
- p->wall_cpu_time_this_debt_interval;
}
total_long_term_debt += p->long_term_debt;
// adjust short term debts
//
if (p->runnable()) {
nrprojects++;
share_frac = p->resource_share/rrs;
p->short_term_debt += share_frac*total_wall_cpu_time_this_debt_interval
- p->wall_cpu_time_this_debt_interval;
total_short_term_debt += p->short_term_debt;
} else {
p->short_term_debt = 0;
p->anticipated_debt = 0;
}
}
if (nprojects==0) return;
// long-term debt:
// normalize so mean is zero,
// short-term debt:
// normalize so mean is zero, and limit abs value at MAX_STD
//
double avg_long_term_debt = total_long_term_debt / nprojects;
double avg_short_term_debt = 0;
if (nrprojects) {
avg_short_term_debt = total_short_term_debt / nrprojects;
}
for (i=0; i<projects.size(); i++) {
p = projects[i];
if (p->non_cpu_intensive) continue;
if (p->runnable()) {
p->short_term_debt -= avg_short_term_debt;
if (p->short_term_debt > MAX_STD) {
p->short_term_debt = MAX_STD;
}
if (p->short_term_debt < -MAX_STD) {
p->short_term_debt = -MAX_STD;
}
}
p->long_term_debt -= avg_long_term_debt;
if (log_flags.debt_debug) {
msg_printf(0, MSG_INFO,
"[debt_debug] adjust_debts(): project %s: STD %f, LTD %f",
p->project_name, p->short_term_debt, p->long_term_debt
);
}
}
reset_debt_accounting();
}
// Decide whether to run the CPU scheduler.
// This is called periodically.
// Scheduled tasks are placed in order of urgency for scheduling in the ordered_scheduled_results vector
//
bool CLIENT_STATE::possibly_schedule_cpus() {
double elapsed_time;
static double last_reschedule=0;
if (projects.size() == 0) return false;
if (results.size() == 0) return false;
// Reschedule every cpu_sched_period seconds,
// or if must_schedule_cpus is set
// (meaning a new result is available, or a CPU has been freed).
//
elapsed_time = now - last_reschedule;
if (elapsed_time >= global_prefs.cpu_scheduling_period()) {
request_schedule_cpus("Scheduling period elapsed.");
}
if (!must_schedule_cpus) return false;
last_reschedule = now;
must_schedule_cpus = false;
schedule_cpus();
return true;
}
void CLIENT_STATE::print_deadline_misses() {
unsigned int i;
RESULT* rp;
PROJECT* p;
for (i=0; i<results.size(); i++){
rp = results[i];
if (rp->rr_sim_misses_deadline && !rp->last_rr_sim_missed_deadline) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] Result %s projected to miss deadline.", rp->name
);
}
else if (!rp->rr_sim_misses_deadline && rp->last_rr_sim_missed_deadline) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] Result %s projected to meet deadline.", rp->name
);
}
}
for (i=0; i<projects.size(); i++) {
p = projects[i];
if (p->rr_sim_deadlines_missed) {
msg_printf(p, MSG_INFO,
"[cpu_sched_debug] Project has %d projected deadline misses",
p->rr_sim_deadlines_missed
);
}
}
}
// CPU scheduler - decide which results to run.
// output: sets ordered_scheduled_result.
//
void CLIENT_STATE::schedule_cpus() {
RESULT* rp;
PROJECT* p;
ACTIVE_TASK* atp;
double expected_pay_off;
unsigned int i;
double rrs = runnable_resource_share();
if (log_flags.cpu_sched_debug) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] schedule_cpus(): start");
}
// do round-robin simulation to find what results miss deadline,
//
rr_simulation();
if (log_flags.cpu_sched_debug) {
print_deadline_misses();
}
adjust_debts();
// set temporary variables
//
for (i=0; i<results.size(); i++) {
rp = results[i];
rp->already_selected = false;
rp->edf_scheduled = false;
}
for (i=0; i<projects.size(); i++) {
p = projects[i];
p->next_runnable_result = NULL;
p->anticipated_debt = p->short_term_debt;
p->deadlines_missed = p->rr_sim_deadlines_missed;
}
for (i=0; i<active_tasks.active_tasks.size(); i++) {
active_tasks.active_tasks[i]->too_large = false;
}
expected_pay_off = global_prefs.cpu_scheduling_period();
ordered_scheduled_results.clear();
double ram_left = available_ram();
// First choose results from projects with P.deadlines_missed>0
//
#ifdef SIM
if (!cpu_sched_rr_only) {
#endif
while ((int)ordered_scheduled_results.size() < ncpus) {
rp = earliest_deadline_result();
if (!rp) break;
rp->already_selected = true;
// see if it fits in available RAM
//
atp = lookup_active_task_by_result(rp);
if (atp) {
if (atp->procinfo.working_set_size_smoothed > ram_left) {
if (log_flags.cpu_sched_debug) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] %s misses deadline but too large: %.2fMB",
rp->name, atp->procinfo.working_set_size_smoothed/MEGA
);
}
atp->too_large = true;
continue;
}
atp->too_large = false;
// TODO: merge this chunk of code with its clone
if (gstate.retry_shmem_time > gstate.now) {
if (atp->app_client_shm.shm == NULL) {
atp->needs_shmem = true;
continue;
}
atp->needs_shmem = false;
}
ram_left -= atp->procinfo.working_set_size_smoothed;
}
rp->project->anticipated_debt -= (rp->project->resource_share / rrs) * expected_pay_off;
rp->project->deadlines_missed--;
rp->edf_scheduled = true;
if (log_flags.cpu_sched_debug) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] scheduling (deadline) %s",
rp->name
);
}
ordered_scheduled_results.push_back(rp);
}
#ifdef SIM
}
#endif
// Next, choose results from projects with large debt
//
while ((int)ordered_scheduled_results.size() < ncpus) {
assign_results_to_projects();
rp = largest_debt_project_best_result();
if (!rp) break;
atp = lookup_active_task_by_result(rp);
if (atp) {
if (atp->procinfo.working_set_size_smoothed > ram_left) {
if (log_flags.cpu_sched_debug) {
msg_printf(NULL, MSG_INFO,
"[cpu_sched_debug] %s too large: %.2fMB",
rp->name, atp->procinfo.working_set_size_smoothed/MEGA
);
}
atp->too_large = true;
continue;
}
atp->too_large = false;
// don't select if it would need a new shared-mem seg
// and we're out of them
//
if (gstate.retry_shmem_time > gstate.now) {
if (atp->app_client_shm.shm == NULL) {
atp->needs_shmem = true;
continue;
}
atp->needs_shmem = false;
}
ram_left -= atp->procinfo.working_set_size_smoothed;
}
double xx = (rp->project->resource_share / rrs) * expected_pay_off;
rp->project->anticipated_debt -= xx;
if (log_flags.cpu_sched_debug) {
msg_printf(NULL, MSG_INFO, "[cpu_sched_debug] scheduling (regular) %s", rp->name);
}
ordered_scheduled_results.push_back(rp);
}
request_enforce_schedule("schedule_cpus");
set_client_state_dirty("schedule_cpus");
}
// make a list of preemptable tasks, ordered by their preemptability.
//
void CLIENT_STATE::make_running_task_heap(
vector<ACTIVE_TASK*> &running_tasks
) {
unsigned int i;
ACTIVE_TASK* atp;
for (i=0; i<active_tasks.active_tasks.size(); i++) {
atp = active_tasks.active_tasks[i];
if (atp->result->project->non_cpu_intensive) continue;
if (!atp->result->runnable()) continue;
if (atp->scheduler_state != CPU_SCHED_SCHEDULED) continue;
running_tasks.push_back(atp);
}
std::make_heap(
running_tasks.begin(),
running_tasks.end(),
more_preemptable
);
}
// Enforce the CPU schedule.
// Inputs:
// ordered_scheduled_results
// List of tasks that should (ideally) run, set by schedule_cpus().
// Most important tasks (e.g. early deadline) are first
// Method:
// Make a list "running_tasks" of currently running tasks
// Most preemptable tasks are first in list.
// Details:
// Initially, each task's scheduler_state is PREEMPTED or SCHEDULED
// depending on whether or not it is running.
// This function sets each task's next_scheduler_state,
// and at the end it starts/resumes and preempts tasks
// based on scheduler_state and next_scheduler_state.
//
bool CLIENT_STATE::enforce_schedule() {
unsigned int i;
ACTIVE_TASK* atp;
vector<ACTIVE_TASK*> running_tasks;
static double last_time = 0;
int retval;
// Do this when requested, and once a minute as a safety net
//
if (now - last_time > 60) {
must_enforce_cpu_schedule = true;
}
if (!must_enforce_cpu_schedule) return false;
must_enforce_cpu_schedule = false;
last_time = now;
bool action = false;
if (log_flags.cpu_sched_debug) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] enforce_schedule(): start");
for (i=0; i<ordered_scheduled_results.size(); i++) {
RESULT* rp = ordered_scheduled_results[i];
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] want to run: %s",
rp->name
);
}
}
// set temporary variables
//
for (i=0; i<projects.size(); i++){
projects[i]->deadlines_missed = projects[i]->rr_sim_deadlines_missed;
}
for (i=0; i< active_tasks.active_tasks.size(); i++) {
atp = active_tasks.active_tasks[i];
if (atp->result->runnable()) {
atp->next_scheduler_state = atp->scheduler_state;
} else {
atp->next_scheduler_state = CPU_SCHED_PREEMPTED;
}
}
// make list of currently running tasks
//
make_running_task_heap(running_tasks);
// if there are more running tasks than ncpus,
// then mark the extras for preemption
//
while (running_tasks.size() > (unsigned int)ncpus) {
running_tasks[0]->next_scheduler_state = CPU_SCHED_PREEMPTED;
std::pop_heap(
running_tasks.begin(),
running_tasks.end(),
more_preemptable
);
running_tasks.pop_back();
}
double ram_left = available_ram();
if (log_flags.mem_usage_debug) {
msg_printf(0, MSG_INFO,
"[mem_usage_debug] enforce: available RAM %.2fMB",
ram_left/MEGA
);
}
// keep track of how many tasks we plan on running
// (i.e. have next_scheduler_state = SCHEDULED)
//
int nrunning = (int)running_tasks.size();
// Loop through the scheduled results
// to see if they should preempt a running task
//
for (i=0; i<ordered_scheduled_results.size(); i++) {
RESULT* rp = ordered_scheduled_results[i];
if (log_flags.cpu_sched_debug) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] processing %s", rp->name
);
}
// See if the result is already running.
//
atp = NULL;
for (vector<ACTIVE_TASK*>::iterator it = running_tasks.begin(); it != running_tasks.end(); it++) {
ACTIVE_TASK *atp1 = *it;
if (atp1 && atp1->result == rp) {
// The task is already running; remove it from the heap
//
atp = atp1;
it = running_tasks.erase(it);
std::make_heap(
running_tasks.begin(),
running_tasks.end(),
more_preemptable
);
break;
}
}
if (atp) {
if (log_flags.cpu_sched_debug) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] %s is already running", rp->name
);
}
// the scheduled result is already running.
// see if it fits in mem
//
if (atp->procinfo.working_set_size_smoothed > ram_left) {
atp->next_scheduler_state = CPU_SCHED_PREEMPTED;
atp->too_large = true;
nrunning--;
if (log_flags.mem_usage_debug) {
msg_printf(rp->project, MSG_INFO,
"[mem_usage_debug] enforce: result %s can't continue, too big %.2fMB > %.2fMB",
rp->name, atp->procinfo.working_set_size_smoothed/MEGA, ram_left/MEGA
);
}
} else {
ram_left -= atp->procinfo.working_set_size_smoothed;
atp->too_large = false;
}
continue;
}
// Here if the result is not already running.
// If it already has a (non-running) active task,
// see if it fits in mem
//
atp = lookup_active_task_by_result(rp);
if (atp) {
if (atp->procinfo.working_set_size_smoothed > ram_left) {
atp->too_large = true;
if (log_flags.mem_usage_debug) {
msg_printf(rp->project, MSG_INFO,
"[mem_usage_debug] enforce: result %s can't start, too big %.2fMB > %.2fMB",
rp->name, atp->procinfo.working_set_size_smoothed/MEGA, ram_left/MEGA
);
}
continue;
} else {
atp->too_large = false;
}
}
// The scheduled result is not already running.
// Preempt something if needed and possible.
//
bool run_task = false;
bool need_to_preempt = (nrunning==ncpus) && running_tasks.size();
// the 2nd half of the above is redundant
if (need_to_preempt) {
// examine the most preemptable task.
// Preempt it if either
// 1) it's completed its time slice and has checkpointed recently
// 2) the scheduled result is in deadline trouble
//
atp = running_tasks[0];
double time_running = now - atp->run_interval_start_wall_time;
bool running_beyond_sched_period = time_running >= global_prefs.cpu_scheduling_period();
double time_since_checkpoint = now - atp->checkpoint_wall_time;
bool checkpointed_recently = time_since_checkpoint < 10;
if (rp->project->deadlines_missed
|| (running_beyond_sched_period && checkpointed_recently)
) {
if (rp->project->deadlines_missed) {
rp->project->deadlines_missed--;
}
atp->next_scheduler_state = CPU_SCHED_PREEMPTED;
nrunning--;
std::pop_heap(
running_tasks.begin(),
running_tasks.end(),
more_preemptable
);
running_tasks.pop_back();
run_task = true;
if (log_flags.cpu_sched_debug) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] preempting %s",
atp->result->name
);
}
} else {
if (log_flags.cpu_sched_debug) {
msg_printf(rp->project, MSG_INFO,
"[cpu_sched_debug] didn't preempt %s: tr %f tsc %f",
atp->result->name, time_running, time_since_checkpoint
);
}
}
} else {
run_task = true;
}
if (run_task) {
atp = get_task(rp);
atp->next_scheduler_state = CPU_SCHED_SCHEDULED;
nrunning++;
ram_left -= atp->procinfo.working_set_size_smoothed;
}
}
if (log_flags.cpu_sched_debug) {
msg_printf(0, MSG_INFO,
"[cpu_sched_debug] finished preempt loop, nrunning %d",
nrunning
);
}
// make sure we don't exceed RAM limits
//
for (i=0; i<running_tasks.size(); i++) {
atp = running_tasks[i];
if (atp->procinfo.working_set_size_smoothed > ram_left) {
atp->next_scheduler_state = CPU_SCHED_PREEMPTED;
atp->too_large = true;
if (log_flags.mem_usage_debug) {
msg_printf(atp->result->project, MSG_INFO,
"[mem_usage_debug] enforce: result %s can't keep, too big %.2fMB > %.2fMB",
atp->result->name, atp->procinfo.working_set_size_smoothed/MEGA, ram_left/MEGA
);
}
} else {
atp->too_large = false;
ram_left -= atp->procinfo.working_set_size_smoothed;
}
}
if (log_flags.cpu_sched_debug && nrunning < ncpus) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] Some CPUs idle (%d<%d)",
nrunning, ncpus
);
request_work_fetch("CPUs idle");
}
if (log_flags.cpu_sched_debug && nrunning > ncpus) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] Too many tasks started (%d>%d)",
nrunning, ncpus
);
}
// schedule new non CPU intensive tasks
//
for (i=0; i<results.size(); i++) {
RESULT* rp = results[i];
if (rp->project->non_cpu_intensive && rp->runnable()) {
atp = get_task(rp);
atp->next_scheduler_state = CPU_SCHED_SCHEDULED;
}
}
double swap_left = (global_prefs.vm_max_used_frac)*host_info.m_swap;
bool check_swap = (host_info.m_swap != 0);
// in case couldn't measure swap on this host
// preempt and start tasks as needed
//
for (i=0; i<active_tasks.active_tasks.size(); i++) {
atp = active_tasks.active_tasks[i];
if (log_flags.cpu_sched_debug) {
msg_printf(atp->result->project, MSG_INFO,
"[cpu_sched_debug] %s sched state %d next %d task state %d",
atp->result->name, atp->scheduler_state,
atp->next_scheduler_state, atp->task_state()
);
}
switch (atp->next_scheduler_state) {
case CPU_SCHED_PREEMPTED:
switch (atp->task_state()) {
case PROCESS_EXECUTING:
action = true;
bool preempt_by_quit = !global_prefs.leave_apps_in_memory;
if (check_swap && swap_left < 0) {
if (log_flags.mem_usage_debug) {
msg_printf(atp->result->project, MSG_INFO,
"[mem_usage_debug] out of swap space, will preempt by quit"
);
}
preempt_by_quit = true;
}
if (atp->too_large) {
if (log_flags.mem_usage_debug) {
msg_printf(atp->result->project, MSG_INFO,
"[mem_usage_debug] job using too much memory, will preempt by quit"
);
}
preempt_by_quit = true;
}
atp->preempt(preempt_by_quit);
break;
}
atp->scheduler_state = CPU_SCHED_PREEMPTED;
break;
case CPU_SCHED_SCHEDULED:
switch (atp->task_state()) {
case PROCESS_UNINITIALIZED:
case PROCESS_SUSPENDED:
action = true;
retval = atp->resume_or_start(
atp->scheduler_state == CPU_SCHED_UNINITIALIZED
);
if ((retval == ERR_SHMGET) || (retval == ERR_SHMAT)) {
// Assume no additional shared memory segs
// will be available in the next 10 seconds
// (run only tasks which are already attached to shared memory).
//
if (gstate.retry_shmem_time < gstate.now) {
request_schedule_cpus("no more shared memory");
}
gstate.retry_shmem_time = gstate.now + 10.0;
continue;
}
if (retval) {
report_result_error(
*(atp->result), "Couldn't start or resume: %d", retval
);
request_schedule_cpus("start failed");
continue;
}
atp->run_interval_start_wall_time = now;
app_started = now;
}
atp->scheduler_state = CPU_SCHED_SCHEDULED;
swap_left -= atp->procinfo.swap_size;
break;
}
}
if (action) {
set_client_state_dirty("enforce_cpu_schedule");
}
if (log_flags.cpu_sched_debug) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] enforce_schedule: end");
}
return action;
}
// return true if we don't have enough runnable tasks to keep all CPUs busy
//
bool CLIENT_STATE::no_work_for_a_cpu() {
unsigned int i;
int count = 0;
for (i=0; i< results.size(); i++){
RESULT* rp = results[i];
if (!rp->nearly_runnable()) continue;
if (rp->project->non_cpu_intensive) continue;
count++;
}
return ncpus > count;
}
// Set the project's rrsim_proc_rate:
// the fraction of each CPU that it will get in round-robin mode.
// Precondition: the project's "active" array is populated
//
void PROJECT::set_rrsim_proc_rate(double rrs) {
int nactive = (int)active.size();
if (nactive == 0) return;
double x;
if (rrs) {
x = resource_share/rrs;
} else {
x = 1; // pathological case; maybe should be 1/# runnable projects
}
// if this project has fewer active results than CPUs,
// scale up its share to reflect this
//
if (nactive < gstate.ncpus) {
x *= ((double)gstate.ncpus)/nactive;
}
// But its rate on a given CPU can't exceed 1
//
if (x>1) {
x = 1;
}
rrsim_proc_rate = x*gstate.overall_cpu_frac();
if (log_flags.rr_simulation) {
msg_printf(this, MSG_INFO,
"[rr_sim] set_rrsim_proc_rate: %f (rrs %f, rs %f, nactive %d, ocf %f",
rrsim_proc_rate, rrs, resource_share, nactive, gstate.overall_cpu_frac()
);
}
}
// Do a simulation of weighted round-robin scheduling.
//
// Inputs:
// per_cpu_proc_rate:
// the expected number of CPU seconds per wall second on each CPU
// rrs:
// the total resource share of relevant projects
// (runnable when called from CPU sched,
// nearly runnable when called from work fetch)
// NOTE: this may be zero, e.g. if no projects have results
//
// Outputs (changes to global state):
// For each project p:
// p->rr_sim_deadlines_missed
// p->cpu_shortfall
// For each result r:
// r->rr_sim_misses_deadline
// r->last_rr_sim_missed_deadline
// gstate.cpu_shortfall
//
// NOTE: deadline misses are not counted for tasks
// that are too large to run in RAM right now.
//
void CLIENT_STATE::rr_simulation() {
double rrs = nearly_runnable_resource_share();
double trs = total_resource_share();
PROJECT* p, *pbest;
RESULT* rp, *rpbest;
vector<RESULT*> active;
unsigned int i;
double x;
vector<RESULT*>::iterator it;
double ar = available_ram();
if (log_flags.rr_simulation) {
msg_printf(0, MSG_INFO,
"[rr_sim] rr_sim start: work_buf_total %f rrs %f trs %f ncpus %d",
work_buf_total(), rrs, trs, ncpus
);
}
// Initialize result lists for each project:
// "active" is what's currently running (in the simulation)
// "pending" is what's queued
//
for (i=0; i<projects.size(); i++) {
p = projects[i];
p->active.clear();
p->pending.clear();
p->rr_sim_deadlines_missed = 0;
p->cpu_shortfall = 0;
}
for (i=0; i<results.size(); i++) {
rp = results[i];
if (!rp->nearly_runnable()) continue;
if (rp->some_download_stalled()) continue;
if (rp->project->non_cpu_intensive) continue;
rp->rrsim_cpu_left = rp->estimated_cpu_time_remaining(false);
p = rp->project;
if (p->active.size() < (unsigned int)ncpus) {
active.push_back(rp);
p->active.push_back(rp);
} else {
p->pending.push_back(rp);
}
rp->last_rr_sim_missed_deadline = rp->rr_sim_misses_deadline;
rp->rr_sim_misses_deadline = false;
}
for (i=0; i<projects.size(); i++) {
p = projects[i];
p->set_rrsim_proc_rate(rrs);
// if there are no results for a project,
// the shortfall is its entire share.
//
if (!p->active.size()) {
double rsf = trs ? p->resource_share/trs : 1;
p->cpu_shortfall = work_buf_total() * overall_cpu_frac() * ncpus * rsf;
if (log_flags.rr_simulation) {
msg_printf(p, MSG_INFO,
"[rr_sim] no results; shortfall %f wbt %f ocf %f rsf %f",
p->cpu_shortfall, work_buf_total(), overall_cpu_frac(), rsf
);
}
}
}
double buf_end = now + work_buf_total();
// Simulation loop. Keep going until work done
//
double sim_now = now;
cpu_shortfall = 0;
while (active.size()) {
// compute finish times and see which result finishes first
//
rpbest = NULL;
for (i=0; i<active.size(); i++) {
rp = active[i];
p = rp->project;
rp->rrsim_finish_delay = rp->rrsim_cpu_left/p->rrsim_proc_rate;
if (!rpbest || rp->rrsim_finish_delay < rpbest->rrsim_finish_delay) {
rpbest = rp;
}
}
pbest = rpbest->project;
if (log_flags.rr_simulation) {
msg_printf(pbest, MSG_INFO,
"[rr_sim] result %s finishes after %f (%f/%f)",
rpbest->name, rpbest->rrsim_finish_delay, rpbest->rrsim_cpu_left, pbest->rrsim_proc_rate
);
}
// "rpbest" is first result to finish. Does it miss its deadline?
//
double diff = sim_now + rpbest->rrsim_finish_delay - ((rpbest->computation_deadline()-now)*CPU_PESSIMISM_FACTOR + now);
if (diff > 0) {
ACTIVE_TASK* atp = lookup_active_task_by_result(rpbest);
if (atp && atp->procinfo.working_set_size_smoothed > ar) {
if (log_flags.rr_simulation) {
msg_printf(pbest, MSG_INFO,
"[rr_sim] result %s misses deadline but too large to run",
rpbest->name
);
}
} else {
rpbest->rr_sim_misses_deadline = true;
pbest->rr_sim_deadlines_missed++;
if (log_flags.rr_simulation) {
msg_printf(pbest, MSG_INFO,
"[rr_sim] result %s misses deadline by %f",
rpbest->name, diff
);
}
}
}
int last_active_size = (int)active.size();
int last_proj_active_size = (int)pbest->active.size();
// remove *rpbest from active set,
// and adjust CPU time left for other results
//
it = active.begin();
while (it != active.end()) {
rp = *it;
if (rp == rpbest) {
it = active.erase(it);
} else {
x = rp->project->rrsim_proc_rate*rpbest->rrsim_finish_delay;
rp->rrsim_cpu_left -= x;
it++;
}
}
// remove *rpbest from its project's active set
//
it = pbest->active.begin();
while (it != pbest->active.end()) {
rp = *it;
if (rp == rpbest) {
it = pbest->active.erase(it);
} else {
it++;
}
}
// If project has more results, add one to active set.
//
if (pbest->pending.size()) {
rp = pbest->pending[0];
pbest->pending.erase(pbest->pending.begin());
active.push_back(rp);
pbest->active.push_back(rp);
}
// If all work done for a project, subtract that project's share
// and recompute processing rates
//
if (pbest->active.size() == 0) {
rrs -= pbest->resource_share;
if (log_flags.rr_simulation) {
msg_printf(pbest, MSG_INFO,
"[rr_sim] decr rrs by %f, new value %f",
pbest->resource_share, rrs
);
}
for (i=0; i<projects.size(); i++) {
p = projects[i];
p->set_rrsim_proc_rate(rrs);
}
}
// increment CPU shortfalls if necessary
//
if (sim_now < buf_end) {
double end_time = sim_now + rpbest->rrsim_finish_delay;
if (end_time > buf_end) end_time = buf_end;
double d_time = end_time - sim_now;
int nidle_cpus = ncpus - last_active_size;
if (nidle_cpus<0) nidle_cpus = 0;
if (nidle_cpus > 0) cpu_shortfall += d_time*nidle_cpus;
double rsf = trs?pbest->resource_share/trs:1;
double proj_cpu_share = ncpus*rsf;
if (last_proj_active_size < proj_cpu_share) {
pbest->cpu_shortfall += d_time*(proj_cpu_share - last_proj_active_size);
if (log_flags.rr_simulation) {
msg_printf(pbest, MSG_INFO,
"[rr_sim] new shortfall %f d_time %f proj_cpu_share %f lpas %d",
pbest->cpu_shortfall, d_time, proj_cpu_share, last_proj_active_size
);
}
}
if (end_time < buf_end) {
d_time = buf_end - end_time;
// if this is the last result for this project, account for the tail
if (!pbest->active.size()) {
pbest->cpu_shortfall += d_time * proj_cpu_share;
if (log_flags.rr_simulation) {
msg_printf(pbest, MSG_INFO, "[rr_sim] proj out of work; shortfall %f d %f pcs %f",
pbest->cpu_shortfall, d_time, proj_cpu_share
);
}
}
}
if (log_flags.rr_simulation) {
msg_printf(0, MSG_INFO,
"[rr_sim] total: idle cpus %d, last active %d, active %d, shortfall %f",
nidle_cpus, last_active_size, (int)active.size(), cpu_shortfall
);
msg_printf(0, MSG_INFO,
"[rr_sim] proj %s: last active %d, active %d, shortfall %f",
pbest->get_project_name(), last_proj_active_size, (int)pbest->active.size(),
pbest->cpu_shortfall
);
}
}
sim_now += rpbest->rrsim_finish_delay;
}
if (sim_now < buf_end) {
cpu_shortfall += (buf_end - sim_now) * ncpus;
}
if (log_flags.rr_simulation) {
for (i=0; i<projects.size(); i++) {
p = projects[i];
if (p->cpu_shortfall) {
msg_printf(p, MSG_INFO,
"[rr_sim] shortfall %f\n", p->cpu_shortfall
);
}
}
msg_printf(NULL, MSG_INFO,
"[rr_sim] done; total shortfall %f\n",
cpu_shortfall
);
}
}
// trigger CPU schedule enforcement.
// Called when a new schedule is computed,
// and when an app checkpoints.
//
void CLIENT_STATE::request_enforce_schedule(const char* where) {
if (log_flags.cpu_sched_debug) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] Request enforce CPU schedule: %s", where);
}
must_enforce_cpu_schedule = true;
}
// trigger CPU scheduling.
// Called when a result is completed,
// when new results become runnable,
// or when the user performs a UI interaction
// (e.g. suspending or resuming a project or result).
//
void CLIENT_STATE::request_schedule_cpus(const char* where) {
if (log_flags.cpu_sched_debug) {
msg_printf(0, MSG_INFO, "[cpu_sched_debug] Request CPU reschedule: %s", where);
}
must_schedule_cpus = true;
}
// Find the active task for a given result
//
ACTIVE_TASK* CLIENT_STATE::lookup_active_task_by_result(RESULT* rep) {
for (unsigned int i = 0; i < active_tasks.active_tasks.size(); i ++) {
if (active_tasks.active_tasks[i]->result == rep) {
return active_tasks.active_tasks[i];
}
}
return NULL;
}
bool RESULT::computing_done() {
return (state() >= RESULT_COMPUTE_ERROR || ready_to_report);
}
// find total resource shares of all projects
//
double CLIENT_STATE::total_resource_share() {
double x = 0;
for (unsigned int i=0; i<projects.size(); i++) {
if (!projects[i]->non_cpu_intensive ) {
x += projects[i]->resource_share;
}
}
return x;
}
// same, but only runnable projects (can use CPU right now)
//
double CLIENT_STATE::runnable_resource_share() {
double x = 0;
for (unsigned int i=0; i<projects.size(); i++) {
PROJECT* p = projects[i];
if (p->non_cpu_intensive) continue;
if (p->runnable()) {
x += p->resource_share;
}
}
return x;
}
// same, but potentially runnable (could ask for work right now)
//
double CLIENT_STATE::potentially_runnable_resource_share() {
double x = 0;
for (unsigned int i=0; i<projects.size(); i++) {
PROJECT* p = projects[i];
if (p->non_cpu_intensive) continue;
if (p->potentially_runnable()) {
x += p->resource_share;
}
}
return x;
}
double CLIENT_STATE::fetchable_resource_share() {
double x = 0;
for (unsigned int i=0; i<projects.size(); i++) {
PROJECT* p = projects[i];
if (p->non_cpu_intensive) continue;
if (p->long_term_debt < -global_prefs.cpu_scheduling_period()) continue;
if (p->contactable()) {
x += p->resource_share;
}
}
return x;
}
// same, but nearly runnable (could be downloading work right now)
//
double CLIENT_STATE::nearly_runnable_resource_share() {
double x = 0;
for (unsigned int i=0; i<projects.size(); i++) {
PROJECT* p = projects[i];
if (p->non_cpu_intensive) continue;
if (p->nearly_runnable()) {
x += p->resource_share;
}
}
return x;
}
bool ACTIVE_TASK::process_exists() {
switch (task_state()) {
case PROCESS_EXECUTING:
case PROCESS_SUSPENDED:
case PROCESS_ABORT_PENDING:
case PROCESS_QUIT_PENDING:
return true;
}
return false;
}
// if there's not an active task for the result, make one
//
ACTIVE_TASK* CLIENT_STATE::get_task(RESULT* rp) {
ACTIVE_TASK *atp = lookup_active_task_by_result(rp);
if (!atp) {
atp = new ACTIVE_TASK;
atp->slot = active_tasks.get_free_slot();
atp->init(rp);
active_tasks.active_tasks.push_back(atp);
}
return atp;
}
// Results must be complete early enough to report before the report deadline.
// Not all hosts are connected all of the time.
//
double RESULT::computation_deadline() {
return report_deadline - (
gstate.work_buf_min()
// Seconds that the host will not be connected to the Internet
+ gstate.global_prefs.cpu_scheduling_period()
// Seconds that the CPU may be busy with some other result
+ DEADLINE_CUSHION
);
}
static const char* result_state_name(int val) {
switch (val) {
case RESULT_NEW: return "NEW";
case RESULT_FILES_DOWNLOADING: return "FILES_DOWNLOADING";
case RESULT_FILES_DOWNLOADED: return "FILES_DOWNLOADED";
case RESULT_COMPUTE_ERROR: return "COMPUTE_ERROR";
case RESULT_FILES_UPLOADING: return "FILES_UPLOADING";
case RESULT_FILES_UPLOADED: return "FILES_UPLOADED";
case RESULT_ABORTED: return "FILES_ABORTED";
}
return "Unknown";
}
void RESULT::set_state(int val, const char* where) {
_state = val;
if (log_flags.task_debug) {
msg_printf(project, MSG_INFO,
"[task_debug] result state=%s for %s from %s",
result_state_name(val), name, where
);
}
}
// called at startup (after get_host_info())
// and when general prefs have been parsed
//
void CLIENT_STATE::set_ncpus() {
int ncpus_old = ncpus;
if (config.ncpus>0) {
ncpus = config.ncpus;
} else if (host_info.p_ncpus>0) {
ncpus = host_info.p_ncpus;
} else {
ncpus = 1;
}
if (ncpus > global_prefs.max_cpus) ncpus = global_prefs.max_cpus;
if (initialized && ncpus != ncpus_old) {
msg_printf(0, MSG_INFO,
"Number of usable CPUs has changed from %d to %d. Running benchmarks.",
ncpus_old, ncpus
);
run_cpu_benchmarks = true;
request_schedule_cpus("Number of usable CPUs has changed");
request_work_fetch("Number of usable CPUs has changed");
}
}
// preempt this task
// called from the CLIENT_STATE::schedule_cpus()
// if quit_task is true do this by quitting
//
int ACTIVE_TASK::preempt(bool quit_task) {
int retval;
// If the app hasn't checkpoint yet, suspend instead of quit
// (accommodate apps that never checkpoint)
//
if (quit_task && (checkpoint_cpu_time>0)) {
if (log_flags.cpu_sched) {
msg_printf(result->project, MSG_INFO,
"[cpu_sched] Preempting %s (removed from memory)",
result->name
);
}
set_task_state(PROCESS_QUIT_PENDING, "preempt");
retval = request_exit();
} else {
if (log_flags.cpu_sched) {
if (quit_task) {
msg_printf(result->project, MSG_INFO,
"[cpu_sched] Preempting %s (left in memory because no checkpoint yet)",
result->name
);
} else {
msg_printf(result->project, MSG_INFO,
"[cpu_sched] Preempting %s (left in memory)",
result->name
);
}
}
retval = suspend();
}
return 0;
}
// The given result has just completed successfully.
// Update the correction factor used to predict
// completion time for this project's results
//
void PROJECT::update_duration_correction_factor(RESULT* rp) {
#ifdef SIM
if (dcf_dont_use) {
duration_correction_factor = 1.0;
return;
}
if (dcf_stats) {
((SIM_PROJECT*)this)->update_dcf_stats(rp);
return;
}
#endif
double raw_ratio = rp->final_cpu_time/rp->estimated_cpu_time_uncorrected();
double adj_ratio = rp->final_cpu_time/rp->estimated_cpu_time(false);
double old_dcf = duration_correction_factor;
// it's OK to overestimate completion time,
// but bad to underestimate it.
// So make it easy for the factor to increase,
// but decrease it with caution
//
if (adj_ratio > 1.1) {
duration_correction_factor = raw_ratio;
} else {
// in particular, don't give much weight to results
// that completed a lot earlier than expected
//
if (adj_ratio < 0.1) {
duration_correction_factor = duration_correction_factor*0.99 + 0.01*raw_ratio;
} else {
duration_correction_factor = duration_correction_factor*0.9 + 0.1*raw_ratio;
}
}
// limit to [.01 .. 100]
//
if (duration_correction_factor > 100) duration_correction_factor = 100;
if (duration_correction_factor < 0.01) duration_correction_factor = 0.01;
if (log_flags.cpu_sched_debug || log_flags.work_fetch_debug) {
msg_printf(this, MSG_INFO,
"[csd|wfd] DCF: %f->%f, raw_ratio %f, adj_ratio %f",
old_dcf, duration_correction_factor, raw_ratio, adj_ratio
);
}
}
const char *BOINC_RCSID_e830ee1 = "$Id$";
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