Re: [PATCH 1/2] powerpc/vcpu: Assume dedicated processors as non-preempt

2019-12-05 Thread Juri Lelli
Hi, On 04/12/19 19:14, Srikar Dronamraju wrote: > With commit 247f2f6f3c70 ("sched/core: Don't schedule threads on pre-empted > vCPUs"), scheduler avoids preempted vCPUs to schedule tasks on wakeup. > This leads to wrong choice of CPU, which in-turn leads to larger wakeup > latencies. Eventually,

Re: [PATCH 1/2] powerpc/vcpu: Assume dedicated processors as non-preempt

2019-12-04 Thread Gautham R Shenoy
Hi Srikar, On Wed, Dec 04, 2019 at 07:14:58PM +0530, Srikar Dronamraju wrote: > With commit 247f2f6f3c70 ("sched/core: Don't schedule threads on pre-empted > vCPUs"), scheduler avoids preempted vCPUs to schedule tasks on wakeup. > This leads to wrong choice of CPU, which in-turn leads to larger wa

Re: [PATCH 1/2] powerpc/vcpu: Assume dedicated processors as non-preempt

2019-12-04 Thread Waiman Long
On 12/4/19 8:44 AM, Srikar Dronamraju wrote: > With commit 247f2f6f3c70 ("sched/core: Don't schedule threads on pre-empted > vCPUs"), scheduler avoids preempted vCPUs to schedule tasks on wakeup. > This leads to wrong choice of CPU, which in-turn leads to larger wakeup > latencies. Eventually, it l

Re: [PATCH 1/2] powerpc/vcpu: Assume dedicated processors as non-preempt

2019-12-04 Thread Srikar Dronamraju
* Srikar Dronamraju [2019-12-04 19:14:58]: > > > # perf stat -a -r 5 ./schbench > v5.4 v5.4 + patch > Latency percentiles (usec) Latency percentiles (usec) > 49.th: 47 50.th: 33 >

[PATCH 1/2] powerpc/vcpu: Assume dedicated processors as non-preempt

2019-12-04 Thread Srikar Dronamraju
With commit 247f2f6f3c70 ("sched/core: Don't schedule threads on pre-empted vCPUs"), scheduler avoids preempted vCPUs to schedule tasks on wakeup. This leads to wrong choice of CPU, which in-turn leads to larger wakeup latencies. Eventually, it leads to performance regression in latency sensitive b