From: Peter Zijlstra <peterz@infradead.org>
To: kernel test robot <yujie.liu@intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
ying.huang@intel.com, feng.tang@intel.com, fengwei.yin@intel.com,
aubrey.li@linux.intel.com, yu.c.chen@intel.com,
Aaron Lu <aaron.lu@intel.com>
Subject: Re: [linus:master] [sched] af7f588d8f: will-it-scale.per_thread_ops -13.9% regression
Date: Mon, 15 May 2023 10:40:07 +0200 [thread overview]
Message-ID: <20230515084007.GF4253@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <202305151017.27581d75-yujie.liu@intel.com>
On Mon, May 15, 2023 at 03:00:44PM +0800, kernel test robot wrote:
> Hello,
>
> kernel test robot noticed a -13.9% regression of will-it-scale.per_thread_ops on:
>
> commit: af7f588d8f7355bc4298dd1962d7826358fc95f0 ("sched: Introduce per-memory-map concurrency ID")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
> testcase: will-it-scale
> test machine: 224 threads 2 sockets (Sapphire Rapids) with 256G memory
> parameters:
>
> test: context_switch1
> cpufreq_governor: performance
>
> test-description: Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two.
> test-url: https://github.com/antonblanchard/will-it-scale
>
> In addition to that, the commit also has significant impact on the following tests:
>
> +------------------+----------------------------------------------------------------------------------------------------+
> | testcase: change | will-it-scale: will-it-scale.per_thread_ops -73.8% regression |
> | test machine | 224 threads 2 sockets (Sapphire Rapids) with 256G memory |
> | test parameters | cpufreq_governor=performance |
> | | mode=thread |
> | | nr_task=16 |
> | | test=context_switch1 |
> +------------------+----------------------------------------------------------------------------------------------------+
> | testcase: change | will-it-scale: will-it-scale.per_thread_ops -57.9% regression |
> | test machine | 104 threads 2 sockets (Skylake) with 192G memory |
> | test parameters | cpufreq_governor=performance |
> | | mode=thread |
> | | nr_task=16 |
> | | test=context_switch1 |
> +------------------+----------------------------------------------------------------------------------------------------+
> | testcase: change | will-it-scale: will-it-scale.per_thread_ops -85.0% regression |
> | test machine | 104 threads 2 sockets (Skylake) with 192G memory |
> | test parameters | cpufreq_governor=performance |
> | | mode=thread |
> | | nr_task=50% |
> | | test=context_switch1 |
> +------------------+----------------------------------------------------------------------------------------------------+
> | testcase: change | vm-scalability: vm-scalability.throughput -9.0% regression |
> | test machine | 96 threads 2 sockets Intel(R) Xeon(R) Platinum 8260L CPU @ 2.40GHz (Cascade Lake) with 128G memory |
> | test parameters | cpufreq_governor=performance |
> | | runtime=300s |
> | | size=2T |
> | | test=shm-xread-seq-mt |
> +------------------+----------------------------------------------------------------------------------------------------+
>
> FYI, we noticed that commit 223baf9d17f2 (sched: Fix performance
> regression introduced by mm_cid) fixed a sysbench regression, but
> will-it-scale context_switch1 benchmark still saw a regression on this
> fix commit.
>
> Furthermore, we applied the code diff in below link [1] on mainline, and
> the will-it-scale score was restored to the original level before this
> patch.
>
> [1] https://lore.kernel.org/lkml/d96164a6-c522-1bfc-8b37-333726cdc573@efficios.com/
>
Right; so I'm thinking we can do that patch -- I'll try and get the
whole lazy TLB thing sorted, but I'm not sure I can find the piece and
quiet to think that over in a hurry :/
prev parent reply other threads:[~2023-05-15 8:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-15 7:00 kernel test robot
2023-05-15 8:40 ` Peter Zijlstra [this message]
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