diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2024-10-10 10:10:05 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-10-17 23:02:27 +0300 |
| commit | 87347f148061b48c3495fb61dcbad384760da9cf (patch) | |
| tree | 22e71d32d1db1766b2c65f7b33775b7071c6e071 /tools/perf/scripts/python/export-to-postgresql.py | |
| parent | 19298f48694987fac843261c84e24834c255b451 (diff) | |
| download | linux-87347f148061b48c3495fb61dcbad384760da9cf.tar.xz | |
futex: Use atomic64_try_cmpxchg_relaxed() in get_inode_sequence_number()
Optimize get_inode_sequence_number() to use simpler and faster:
!atomic64_try_cmpxchg_relaxed(*ptr, &old, new)
instead of:
atomic64_cmpxchg relaxed(*ptr, old, new) != old
The x86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg. The generated
code improves from:
3da: 31 c0 xor %eax,%eax
3dc: f0 48 0f b1 8a 38 01 lock cmpxchg %rcx,0x138(%rdx)
3e3: 00 00
3e5: 48 85 c0 test %rax,%rax
3e8: 48 0f 44 c1 cmove %rcx,%rax
to:
3da: 31 c0 xor %eax,%eax
3dc: f0 48 0f b1 8a 38 01 lock cmpxchg %rcx,0x138(%rdx)
3e3: 00 00
3e5: 48 0f 44 c1 cmove %rcx,%rax
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/all/20241010071023.21913-2-ubizjak@gmail.com
Diffstat (limited to 'tools/perf/scripts/python/export-to-postgresql.py')
0 files changed, 0 insertions, 0 deletions