Messages in this thread | | | Subject | Re: [RFC][PATCH 3/2] x86/jump labels: Count and display the short jumps used | From | Steven Rostedt <> | Date | Wed, 07 Aug 2013 16:33:26 -0400 |
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On Wed, 2013-08-07 at 16:19 -0400, Jason Baron wrote:
> The whole point of the thread started with wanting to move the default > 'disabled' branch further out-of-line. We could get there with better > compiler support for the 'cold' label attribute. Thus, in theory the > whole 2-byte jmp is just an intermediate step. (Yeah, I know that > support doesn't seem to be happening anytime soon...) >
Actually, Ideally, we would move the bulk of the tracing code out of line, but we can have the jump to the tracing code still in line, and the nop jump to it.
[ hot path] jmp trace / nop 1:
[...]
trace: jmp trace_main_code jmp 1b
Then that jmp trace can still be a 2 byte op.
-- Steve
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