From: Xi Ruoyao <xry111@xry111.site>
To: libc-alpha@sourceware.org
Subject: posix_memalign performance regression in 2.38?
Date: Fri, 04 Aug 2023 10:52:44 +0800 [thread overview]
Message-ID: <68e8c4eb66697f2f2cd37bf9456b60aabf7e1bc5.camel@xry111.site> (raw)
Hi,
There seems a performance regression of posix_memalign in Glibc-2.38:
$ cat t.c
#include <stdlib.h>
int main()
{
void *buf;
for (int i = 0; i < (1 << 16); i++)
posix_memalign(&buf, 64, 16);
}
$ cc t.c
$ time ./a.out
real 0m0.008s
user 0m0.005s
sys 0m0.003s
$ time ~/sources/lfs/glibc-2.38/build/testrun.sh ./a.out
real 0m4.376s
user 0m4.369s
sys 0m0.007s
The behavior seems worse than quadratic: if I change "1 << 16" to "1 <<
17", I get:
$ time ~/sources/lfs/glibc-2.38/build/testrun.sh ./a.out
real 0m28.597s
user 0m28.568s
sys 0m0.022s
I've not bisected for this yet.
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
next reply other threads:[~2023-08-04 2:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-04 2:52 Xi Ruoyao [this message]
2023-08-04 14:12 ` Adhemerval Zanella Netto
2023-08-07 19:49 ` DJ Delorie
2023-08-07 19:57 ` Sam James
2023-08-07 20:15 ` DJ Delorie
2023-08-08 3:38 ` DJ Delorie
2023-08-08 8:08 ` Xi Ruoyao
2023-08-08 15:08 ` DJ Delorie
2023-08-09 10:47 ` Florian Weimer
2023-08-09 16:59 ` Florian Weimer
2023-08-07 19:58 ` Noah Goldstein
2023-08-07 20:07 ` DJ Delorie
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