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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2007-07-19 21:28:35 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-07-19 21:28:35 +0200 |
| commit | 9439aab8dbc33c2c03c3a19dba267360383ba38c (patch) | |
| tree | b6405b709b7bf60216290f9d81aec133faea6adf /kernel | |
| parent | [PATCH] sched: sched_cacheflush is now unused (diff) | |
| download | linux-9439aab8dbc33c2c03c3a19dba267360383ba38c.tar.xz linux-9439aab8dbc33c2c03c3a19dba267360383ba38c.zip | |
[PATCH] sched: fix newly idle load balance in case of SMT
In the presence of SMT, newly idle balance was never happening for
multi-core and SMP domains (even when both the logical siblings are
idle).
If thread 0 is already idle and when thread 1 is about to go to idle,
newly idle load balance always think that one of the threads is not idle
and skips doing the newly idle load balance for multi-core and SMP
domains.
This is because of the idle_cpu() macro, which checks if the current
process on a cpu is an idle process. But this is not the case for the
thread doing the load_balance_newidle().
Fix this by using runqueue's nr_running field instead of idle_cpu(). And
also skip the logic of 'only one idle cpu in the group will be doing
load balancing' during newly idle case.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 645256b228c3..e36d99d1ddb1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2235,7 +2235,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, rq = cpu_rq(i); - if (*sd_idle && !idle_cpu(i)) + if (*sd_idle && rq->nr_running) *sd_idle = 0; /* Bias balancing toward cpus of our domain */ @@ -2257,9 +2257,11 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, /* * First idle cpu or the first cpu(busiest) in this sched group * is eligible for doing load balancing at this and above - * domains. + * domains. In the newly idle case, we will allow all the cpu's + * to do the newly idle load balance. */ - if (local_group && balance_cpu != this_cpu && balance) { + if (idle != CPU_NEWLY_IDLE && local_group && + balance_cpu != this_cpu && balance) { *balance = 0; goto ret; } |