mirror of
https://github.com/torvalds/linux
synced 2024-10-08 12:22:38 +00:00
d0618410ec
In an XDP redirect applications using tracepoint xdp:xdp_redirect to diagnose TX overrun, I noticed perf_swevent_get_recursion_context() was consuming 2% CPU. This was reduced to 1.85% with this simple change. Looking at the annotated asm code, it was clear that the unlikely case in_nmi() test was chosen (by the compiler) as the most likely event/branch. This small adjustment makes the compiler (GCC version 7.1.1 20170622 (Red Hat 7.1.1-3)) put in_nmi() as an unlikely branch. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150342256382.16595.986861478681783732.stgit@firesoul Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|---|---|---|
| .. | ||
| callchain.c | ||
| core.c | ||
| hw_breakpoint.c | ||
| internal.h | ||
| Makefile | ||
| ring_buffer.c | ||
| uprobes.c | ||