From: Shakeel Butt <shakeelb@google.com>
To: Jiebin Sun <jiebin.sun@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
vasily.averin@linux.dev, Dennis Zhou <dennis@kernel.org>,
Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Alexey Gladkov <legion@kernel.org>,
Manfred Spraul <manfred@colorfullife.com>,
alexander.mikhalitsyn@virtuozzo.com,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
"Chen, Tim C" <tim.c.chen@intel.com>,
Feng Tang <feng.tang@intel.com>,
Huang Ying <ying.huang@intel.com>,
tianyou.li@intel.com, wangyang.guo@intel.com
Subject: Re: [PATCH] ipc/msg.c: mitigate the lock contention with percpu counter
Date: Fri, 2 Sep 2022 09:27:54 -0700 [thread overview]
Message-ID: <CALvZod44uUFnwfF4StC24t+d1s_XE10hkmSCgb04FjtTATo6xQ@mail.gmail.com> (raw)
In-Reply-To: <20220902152243.479592-1-jiebin.sun@intel.com>
On Fri, Sep 2, 2022 at 12:04 AM Jiebin Sun <jiebin.sun@intel.com> wrote:
>
> The msg_bytes and msg_hdrs atomic counters are frequently
> updated when IPC msg queue is in heavy use, causing heavy
> cache bounce and overhead. Change them to percpu_counters
> greatly improve the performance. Since there is one unique
> ipc namespace, additional memory cost is minimal. Reading
> of the count done in msgctl call, which is infrequent. So
> the need to sum up the counts in each CPU is infrequent.
>
> Apply the patch and test the pts/stress-ng-1.4.0
> -- system v message passing (160 threads).
>
> Score gain: 3.38x
>
> CPU: ICX 8380 x 2 sockets
> Core number: 40 x 2 physical cores
> Benchmark: pts/stress-ng-1.4.0
> -- system v message passing (160 threads)
>
> Signed-off-by: Jiebin Sun <jiebin.sun@intel.com>
[...]
>
> +void percpu_counter_add_local(struct percpu_counter *fbc, s64 amount)
> +{
> + this_cpu_add(*fbc->counters, amount);
> +}
> +EXPORT_SYMBOL(percpu_counter_add_local);
Why not percpu_counter_add()? This may drift the fbc->count more than
batch*nr_cpus. I am assuming that is not the issue for you as you
always do an expensive sum in the slow path. As Andrew asked, this
should be a separate patch.
next prev parent reply other threads:[~2022-09-02 16:28 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-02 15:22 [PATCH] ipc/msg.c: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-02 16:06 ` Andrew Morton
2022-09-05 11:54 ` Sun, Jiebin
2022-09-02 16:27 ` Shakeel Butt [this message]
2022-09-05 12:02 ` Sun, Jiebin
2022-09-06 18:44 ` Tim Chen
2022-09-07 9:39 ` Sun, Jiebin
2022-09-07 20:43 ` Andrew Morton
2022-09-07 17:25 ` [PATCH v4] ipc/msg: " Jiebin Sun
2022-09-07 16:01 ` Tim Chen
2022-09-07 21:34 ` Andrew Morton
2022-09-07 22:10 ` Tim Chen
2022-09-08 8:25 ` Sun, Jiebin
2022-09-08 15:38 ` Andrew Morton
2022-09-08 16:15 ` Dennis Zhou
2022-09-03 19:35 ` [PATCH] ipc/msg.c: " Manfred Spraul
2022-09-05 12:12 ` Sun, Jiebin
2022-09-05 19:35 ` [PATCH v2 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-05 19:35 ` [PATCH v2 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-05 19:35 ` [PATCH v2 1/2] percpu: Add percpu_counter_add_local Jiebin Sun
2022-09-05 19:31 ` Shakeel Butt
2022-09-06 8:41 ` Sun, Jiebin
2022-09-06 16:54 ` [PATCH v3 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-06 16:54 ` [PATCH v3 1/2] percpu: Add percpu_counter_add_local Jiebin Sun
2022-09-06 16:54 ` [PATCH v3 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-09 20:36 ` [PATCH v5 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-09 20:36 ` [PATCH v5 1/2] percpu: Add percpu_counter_add_local and percpu_counter_sub_local Jiebin Sun
2022-09-09 16:37 ` Tim Chen
2022-09-10 1:37 ` kernel test robot
2022-09-10 8:15 ` kernel test robot
2022-09-10 8:26 ` kernel test robot
2022-09-09 20:36 ` [PATCH v5 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-09 16:11 ` Tim Chen
2022-09-13 19:25 ` [PATCH v6 0/2] ipc/msg: mitigate the lock contention in ipc/msg Jiebin Sun
2022-09-13 19:25 ` [PATCH v6 1/2] percpu: Add percpu_counter_add_local and percpu_counter_sub_local Jiebin Sun
2022-09-18 11:08 ` Manfred Spraul
2022-09-20 6:01 ` Sun, Jiebin
2022-09-13 19:25 ` [PATCH v6 2/2] ipc/msg: mitigate the lock contention with percpu counter Jiebin Sun
2022-09-18 12:53 ` Manfred Spraul
2022-09-20 2:36 ` Sun, Jiebin
2022-09-20 4:53 ` Manfred Spraul
2022-09-20 5:50 ` Sun, Jiebin
2022-09-20 15:08 ` [PATCH] ipc/msg: avoid negative value by overflow in msginfo Jiebin Sun
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