diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2023-11-20 15:33:45 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-11-21 13:57:30 +0100 |
| commit | c516213726fb572700cce4a5909aa8d82b77192a (patch) | |
| tree | 58e59e4af6716d5276dd928e75e4a0d3fbd1a048 /scripts/gdb/linux/proc.py | |
| parent | 98b1cc82c4affc16f5598d4fa14b1858671b2263 (diff) | |
x86/entry: Optimize common_interrupt_return()
The code in common_interrupt_return() does a bunch of unconditional
work that is really only needed on PTI kernels. Specifically it
unconditionally copies the IRET frame back onto the entry stack,
swizzles onto the entry stack and does IRET from there.
However, without PTI we can simply IRET from whatever stack we're on.
ivb-ep, mitigations=off, gettid-1m:
PRE:
140,118,538 cycles:k ( +- 0.01% )
236,692,878 instructions:k # 1.69 insn per cycle ( +- 0.00% )
POST:
140,026,608 cycles:k ( +- 0.01% )
236,696,176 instructions:k # 1.69 insn per cycle ( +- 0.00% )
(this is with --repeat 100 and the run-to-run variance is bigger than
the difference shown)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231120143626.638107480@infradead.org
Diffstat (limited to 'scripts/gdb/linux/proc.py')
0 files changed, 0 insertions, 0 deletions