| Message ID | 1338965571-9812-1-git-send-email-alex.shi@intel.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Wed, 2012-06-06 at 14:52 +0800, Alex Shi wrote: > - if (sched_domains_numa_distance[level] > REMOTE_DISTANCE) > + if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) I actually considered this.. I just felt a little uneasy re-purposing the RECLAIM_DISTANCE for this, but I guess its all the same anyway. Both mean expensive-away-distance. So I've taken this. thanks!
Hello. On 06-06-2012 10:52, Alex Shi wrote: > commit cb83b629b Please also specify that commit's summary in parens. > remove the NODE sched domain and check if the node > distance in SLIT table is farther than REMOTE_DISTANCE, if so, it will > lose the load balance chance at exec/fork/wake_affine points. > But actually, even the node distance is farther than REMOTE_DISTANCE, > Modern CPUs also has QPI like connections, that make memory access is "Is" not needed here. > not too slow between nodes. So above losing on NUMA machine make a > huge performance regression on benchmark: hackbench, tbench, netperf > and oltp etc. > This patch will recover the scheduler behavior to old mode on all my > Intel platforms: NHM EP/EX, WSM EP, SNB EP/EP4S, and so remove the > perfromance regressions. (all of them just has 2 kinds distance, 10 21) > Signed-off-by: Alex Shi<alex.shi@intel.com> WBR, Sergei
On 06/06/2012 05:01 PM, Peter Zijlstra wrote: > On Wed, 2012-06-06 at 14:52 +0800, Alex Shi wrote: >> - if (sched_domains_numa_distance[level] > REMOTE_DISTANCE) >> + if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) > > I actually considered this.. I just felt a little uneasy re-purposing > the RECLAIM_DISTANCE for this, but I guess its all the same anyway. Both > mean expensive-away-distance. > I understand you, the BIOS guys don't have a good alignment with us on this. > So I've taken this. > > thanks!
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 39eb601..b2ee41a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6286,7 +6286,7 @@ static int sched_domains_curr_level; static inline int sd_local_flags(int level) { - if (sched_domains_numa_distance[level] > REMOTE_DISTANCE) + if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) return 0; return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE;
commit cb83b629b remove the NODE sched domain and check if the node distance in SLIT table is farther than REMOTE_DISTANCE, if so, it will lose the load balance chance at exec/fork/wake_affine points. But actually, even the node distance is farther than REMOTE_DISTANCE, Modern CPUs also has QPI like connections, that make memory access is not too slow between nodes. So above losing on NUMA machine make a huge performance regression on benchmark: hackbench, tbench, netperf and oltp etc. This patch will recover the scheduler behavior to old mode on all my Intel platforms: NHM EP/EX, WSM EP, SNB EP/EP4S, and so remove the perfromance regressions. (all of them just has 2 kinds distance, 10 21) Signed-off-by: Alex Shi <alex.shi@intel.com> --- kernel/sched/core.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)