Re: [linux-next:master] [mm] 8f33a2ff30: stress-ng.resched.ops_per_sec -10.3% regression

Uladzislau Rezki
2024-02-29T18:21:41Z

Hello.

>
>
> Hello,
>
> kernel test robot noticed a -10.3% regression of stress-ng.resched.ops_per_sec on:
>
>
> commit: 8f33a2ff307248c3e55a7696f60b3658b28edb57 ("mm: vmalloc: set nr_nodes based on CPUs in a system")
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
>
> testcase: stress-ng
> test machine: 64 threads 2 sockets Intel(R) Xeon(R) Gold 6346 CPU @ 3.10GHz (Ice Lake) with 256G memory
> parameters:
>
> nr_threads: 100%
> testtime: 60s
> test: resched
> cpufreq_governor: performance
>
>
> In addition to that, the commit also has significant impact on the following tests:
>
> +------------------+-------------------------------------------------------------------------------------------+
> | testcase: change | stress-ng: stress-ng.pthread.ops_per_sec 23.0% improvement |
> | test machine | 64 threads 2 sockets Intel(R) Xeon(R) Gold 6346 CPU @ 3.10GHz (Ice Lake) with 256G memory |
> | test parameters | cpufreq_governor=performance |
> | | nr_threads=100% |
> | | test=pthread |
> | | testtime=60s |
> +------------------+-------------------------------------------------------------------------------------------+
> | testcase: change | stress-ng: stress-ng.fstat.ops_per_sec 14.2% improvement |
> | test machine | 64 threads 2 sockets Intel(R) Xeon(R) Gold 6346 CPU @ 3.10GHz (Ice Lake) with 256G memory |
> | test parameters | cpufreq_governor=performance |
> | | disk=1HDD |
> | | fs=xfs |
> | | nr_threads=100% |
> | | test=fstat |
> | | testtime=60s |
> +------------------+-------------------------------------------------------------------------------------------+
>
This is good if i understand this correctly.

>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202402292306.8520763a-oliver.sang@intel.com
>
>
> Details are as below:
> -------------------------------------------------------------------------------------------------->
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20240229/202402292306.8520763a-oliver.sang@intel.com
>
> =========================================================================================
> compiler/cpufreq_governor/kconfig/nr_threads/rootfs/tbox_group/test/testcase/testtime:
> gcc-12/performance/x86_64-rhel-8.3/100%/debian-12-x86_64-20240206.cgz/lkp-icl-2sp7/resched/stress-ng/60s
>
> commit:
> 8e1d743f2c ("mm: vmalloc: support multiple nodes in vmallocinfo")
> 8f33a2ff30 ("mm: vmalloc: set nr_nodes based on CPUs in a system")
>
> 8e1d743f2c2671aa 8f33a2ff307248c3e55a7696f60
> ---------------- ---------------------------
> %stddev %change %stddev
> \ | \
> 7.48 -0.8 6.73 mpstat.cpu.all.nice%
> 10439977 -10.4% 9351864 vmstat.system.cs
> 14670714 ± 3% +18.1% 17330709 ± 5% numa-numastat.node0.local_node
> 14688319 ± 3% +18.1% 17348214 ± 5% numa-numastat.node0.numa_hit
> 14538034 ± 3% +15.7% 16824234 ± 4% numa-numastat.node1.local_node
> 14556613 ± 3% +15.6% 16834659 ± 4% numa-numastat.node1.numa_hit
> 14685240 ± 3% +18.0% 17334251 ± 5% numa-vmstat.node0.numa_hit
> 14667635 ± 3% +18.1% 17316745 ± 5% numa-vmstat.node0.numa_local
> 14551744 ± 3% +15.6% 16815047 ± 4% numa-vmstat.node1.numa_hit
> 14533165 ± 3% +15.6% 16804623 ± 4% numa-vmstat.node1.numa_local
> 9.153e+08 -10.3% 8.208e+08 stress-ng.resched.ops
> 15220752 -10.3% 13651349 stress-ng.resched.ops_per_sec
> 6.584e+08 -10.8% 5.871e+08 stress-ng.time.involuntary_context_switches
>
This is not. I am working on it to figure out what happens.

--
Uladzislau Rezki