From cffbef137293e4eebf9df5952e569a4bd96386ef Mon Sep 17 00:00:00 2001
From: David Anderson <davea@ssl.berkeley.edu>
Date: Fri, 18 Sep 2009 17:11:15 +0000
Subject: [PATCH] - client: in choosing coproc jobs to run (FIFO) give priority
     to whether job is already running.     This addresses a bug where several
 jobs are returned by sched RPC,     and one with a lexicographically greater
 name     happens to finish downloading first.

svn path=/trunk/boinc/; revision=19092
---
 checkin_notes        | 10 ++++++++++
 client/cpu_sched.cpp | 12 +++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/checkin_notes b/checkin_notes
index 8deff08a96..1deef26b58 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -7856,3 +7856,13 @@ David  18 Sept 2009
         sysmon_win.cpp
     lib/
         proxy_info.cpp,h
+
+David  18 Sept 2009
+    - client: in choosing coproc jobs to run (FIFO) give priority
+        to whether job is already running.
+        This addresses a bug where several jobs are returned by sched RPC,
+        and one with a lexicographically greater name
+        happens to finish downloading first.
+
+    client/
+        cpu_sched.cpp
diff --git a/client/cpu_sched.cpp b/client/cpu_sched.cpp
index 2972aeba71..9095652c46 100644
--- a/client/cpu_sched.cpp
+++ b/client/cpu_sched.cpp
@@ -306,7 +306,11 @@ RESULT* CLIENT_STATE::largest_debt_project_best_result() {
     return rp;
 }
 
-// return coproc jobs in FIFO order
+// Return coproc jobs in FIFO order
+// Give priority to already-started jobs because of the following scenario:
+// - client gets several jobs in a sched reply and starts download files
+// - a job with a later name happens to finish downloading first, and starts
+// - a job with an earlier name finishes downloading and preempts
 //
 RESULT* first_coproc_result() {
     unsigned int i;
@@ -321,10 +325,12 @@ RESULT* first_coproc_result() {
             best = rp;
             continue;
         }
-        if (rp->received_time < best->received_time) {
+        if (!rp->not_started() && best->not_started()) {
+            best = rp;
+        } else if (rp->received_time < best->received_time) {
             best = rp;
         } else if (rp->received_time == best->received_time) {
-            // make it deterministic
+            // make it deterministic by looking at name
             //
             if (strcmp(rp->name, best->name)) {
                 best = rp;