From: Florian Weimer <fweimer@redhat.com>
To: Yang Yanchao via Libc-alpha <libc-alpha@sourceware.org>
Cc: Yang Yanchao <yangyanchao6@huawei.com>,
ldv@altlinux.org, linfeilong@huawei.com,
siddhesh@sourceware.org
Subject: Re: malloc: Optimize the number of arenas for better application performance
Date: Tue, 28 Jun 2022 13:18:26 +0200 [thread overview]
Message-ID: <87bkudghod.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <4ffb458f-9c32-f0e5-8503-44838d87defe@huawei.com> (Yang Yanchao via Libc-alpha's message of "Tue, 28 Jun 2022 17:40:23 +0800")
* Yang Yanchao via Libc-alpha:
> At Kunpeng920 platform, tpcc-mysql scores decreased by about 11.2%
> between glibc-2.36 and glibc2.28.
> Comparing the code, I find that the two commits causes performance
> degradation.
> 11a02b035b46 (misc: Add __get_nprocs_sched)
> 97ba273b5057 (linux: __get_nprocs_sched: do not feed CPU_COUNT_S with
> garbage [BZ #28850])
>
> These two patches modify the default behavior.
> However, my machine is 96 cores and I have 91 cores bound.
> It means that perhaps the current way of computing arenas is not optimal.
> So I roll back some of the code submitted by 11a02b035(misc: Add
> __get_nprocs_sched).
>
> ---
> malloc/arena.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/malloc/arena.c b/malloc/arena.c
> index 0a684a720d..a1ee7928d3 100644
> --- a/malloc/arena.c
> +++ b/malloc/arena.c
> @@ -937,7 +937,7 @@ arena_get2 (size_t size, mstate avoid_arena)
> narenas_limit = mp_.arena_max;
> else if (narenas > mp_.arena_test)
> {
> - int n = __get_nprocs_sched ();
> + int n = __get_nprocs ();
>
> if (n >= 1)
> narenas_limit = NARENAS_FROM_NCORES (n);
How many threads does tpcc-mysql create?
I wonder if all threads get their own arena with the larger count, and
there is some arena sharing with the smaller count.
Thanks,
Florian
next prev parent reply other threads:[~2022-06-28 11:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 9:40 Yang Yanchao
2022-06-28 11:18 ` Florian Weimer [this message]
2022-06-28 12:38 ` Siddhesh Poyarekar
2022-06-28 13:35 ` Adhemerval Zanella
2022-06-28 18:56 ` DJ Delorie
2022-06-28 19:17 ` Adhemerval Zanella
[not found] ` <1a8f10e034e7489c8e9f090e9c90b396@huawei.com>
2022-06-29 2:37 ` 转发: " Qingqing Li
2022-06-29 5:25 ` Siddhesh Poyarekar
2022-06-29 8:05 ` [PATCH] malloc: Optimize the number of arenas for better application performance [BZ# 29296] Yang Yanchao
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