Reproducer with a Jammy LXD container.
System with 56 processors ("threads").
LXD and gcc setup:
$ lxc launch ubuntu:jammy glibc-jammy
$ lxc exec glibc-jammy -- su - ubuntu
$ wget -O test-glibc-malloc.c
https://sourceware.org/bugzilla/attachment.cgi?id=15156
$ sudo apt update
$ sudo apt install --yes gcc
$ gcc -o test-glibc-malloc test-glibc-malloc.c
$ nproc
56
$ dpkg -s libc6 | grep Version:
Version: 2.35-0ubuntu3.8
Without per-CPU affinity (average: 70ms)
$ ./test-glibc-malloc 56 false false
nr_cpu: 56 pin: no fix: no
thread average (ms): 82.383206
$ ./test-glibc-malloc 56 false false
nr_cpu: 56 pin: no fix: no
thread average (ms): 64.518794
$ ./test-glibc-malloc 56 false false
nr_cpu: 56 pin: no fix: no
thread average (ms): 75.425471
$ ./test-glibc-malloc 56 false false
nr_cpu: 56 pin: no fix: no
thread average (ms): 64.692622
$ ./test-glibc-malloc 56 false false
nr_cpu: 56 pin: no fix: no
thread average (ms): 63.640988
With per-CPU affinity (average: 15700ms)
$ ./test-glibc-malloc 56 true false
nr_cpu: 56 pin: yes fix: no
thread average (ms): 15942.782619
$ ./test-glibc-malloc 56 true false
nr_cpu: 56 pin: yes fix: no
thread average (ms): 15555.405825
$ ./test-glibc-malloc 56 true false
nr_cpu: 56 pin: yes fix: no
thread average (ms): 16291.390243
$ ./test-glibc-malloc 56 true false
nr_cpu: 56 pin: yes fix: no
thread average (ms): 16559.855197
$ ./test-glibc-malloc 56 true false
nr_cpu: 56 pin: yes fix: no
thread average (ms): 14171.939208
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https://bugs.launchpad.net/bugs/2089789
Title:
malloc performance degradation with CPU affinity masks
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