Some snippets (more line breaks for clarity) from
https://sourceware.org/bugzilla/show_bug.cgi?id=30945
"""
<...> The deserialization library we used works 10x slower than
expected.
Investigations show that this is due to the arena_get2 function uses
__get_nprocs_sched instead of __get_nprocs.
Without changing core affinity settings, this call returns the real
number
of cores so the upper limit of total arenas is set correctly.
However, if a thread is pinned to a core, further malloc calls only sees
n = 1 because the function returns only schedulable cores.
Therefore, the maximum number of arenas will be 8 on 64-bit
platforms.
<...>
./a.out 32 false false
---
nr_cpu: 32 pin: no fix: no
thread average (ms): 16.233663
./a.out 32 true false
---
nr_cpu: 32 pin: yes fix: no
thread average (ms): 1360.919047
<...>
Fixed on 2.39.
<...>
I backported it to 2.34, 2.35, 2.36, 2.37, and 2.38.
"""
** Bug watch added: Sourceware.org Bugzilla #30945
https://sourceware.org/bugzilla/show_bug.cgi?id=30945
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https://bugs.launchpad.net/bugs/2089789
Title:
malloc performance degradation with CPU affinity masks
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