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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-02-10 08:44:09 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-02-11 23:35:13 +1100 |
| commit | 5b90b9661a3396e00f6e8bcbb617a0787fb683d0 (patch) | |
| tree | 8aca57352d6e9e8138b62804c364d0fa0fdbaf62 /tools/perf/scripts/python/export-to-sqlite.py | |
| parent | d524dda719f06967db4d3ba519edf9267f84c155 (diff) | |
powerpc/syscall: Avoid storing 'current' in another pointer
By saving the pointer pointing to thread_info.flags, gcc copies r2
in a non-volatile register.
We know 'current' doesn't change, so avoid that intermediaite pointer.
Reduces null_syscall benchmark by 2 cycles (322 => 320 cycles)
On PPC64, gcc seems to know that 'current' is not changing, and it keeps
it in a non volatile register to avoid multiple read of 'current' in paca.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ad0363ff0ff8c125f40e1cdc589a85bbd7e31693.1612946484.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'tools/perf/scripts/python/export-to-sqlite.py')
0 files changed, 0 insertions, 0 deletions