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- scheduler: problem: in the daily quota mechanism, 

the boundary between days is 00:00 in server local time.
    This creates a spike of jobs being dispatched
    (and files being downloaded) after that time.

    Solution: distribute the boundary uniformly,
    using a random number determined by the host ID.
    (Make sure to save/restore the seed around this,
    so we don't destroy the randomness of other things)


svn path=/trunk/boinc/; revision=24353
This commit is contained in:
David Anderson 2011-10-08 05:17:44 +00:00
parent ab30d18736
commit 279c3a2b37
2 changed files with 25 additions and 2 deletions
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14
checkin_notes
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@ -6969,3 +6969,17 @@ Charlie 7 Oct 2011
coproc_detect.cpp
lib/
coproc.cpp,h
David 7 Oct 2011
- scheduler: problem: in the daily quota mechanism,
the boundary between days is 00:00 in server local time.
This creates a spike of jobs being dispatched
(and files being downloaded) after that time.
Solution: distribute the boundary uniformly,
using a random number determined by the host ID.
(Make sure to save/restore the seed around this,
so we don't destroy the randomness of other things)
sched/
handle_request.cpp

13
sched/handle_request.cpp
View File

@ -1075,7 +1075,7 @@ static inline bool requesting_work() {
void process_request(char* code_sign_key) {
PLATFORM* platform;
int retval;
double last_rpc_time;
double last_rpc_time, x;
struct tm *rpc_time_tm;
bool ok_to_send_work = !config.dont_send_jobs;
bool have_no_work = false;
@ -1195,13 +1195,22 @@ void process_request(char* code_sign_key) {
}
}
// in deciding whether it's a new day,
// add a random factor (based on host ID)
// to smooth out network traffic over the day
//
retval = rand();
srand(g_reply->host.id);
x = drand()*86400;
srand(retval);
last_rpc_time = g_reply->host.rpc_time;
t = g_reply->host.rpc_time;
t = g_reply->host.rpc_time + x;
rpc_time_tm = localtime(&t);
g_request->last_rpc_dayofyear = rpc_time_tm->tm_yday;
t = time(0);
g_reply->host.rpc_time = t;
t += x;
rpc_time_tm = localtime(&t);
g_request->current_rpc_dayofyear = rpc_time_tm->tm_yday;