diff options
author | Peter Zijlstra <peterz@infradead.org> | 2013-10-31 17:20:25 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2013-11-06 12:34:19 +0100 |
commit | c72b42a3dde487132da80202756c101b371b2add (patch) | |
tree | 5e6771876f565957aae8caab8e6abddba707f5be /fs/fuse | |
parent | 26c86da8821f7b64fced498674990318bc34c8de (diff) |
perf: Add unlikely() to the ring-buffer code
Add unlikely() annotations to 'slow' paths:
When having a sampling event but no output buffer; you have bigger
issues -- also the bail is still faster than actually doing the work.
When having a sampling event but a control page only buffer, you have
bigger issues -- again the bail is still faster than actually doing
work.
Optimize for the case where you're not loosing events -- again, not
doing the work is still faster but make sure that when you have to
actually do work its as fast as possible.
The typical watermark is 1/2 the buffer size, so most events will not
take this path.
Shrinks perf_output_begin() by 16 bytes on x86_64-defconfig.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Michael Neuling <mikey@neuling.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: james.hogan@imgtec.com
Cc: Vince Weaver <vince@deater.net>
Cc: Victor Kaplansky <VICTORK@il.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Anton Blanchard <anton@samba.org>
Link: http://lkml.kernel.org/n/tip-wlg3jew3qnutm8opd0hyeuwn@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs/fuse')
0 files changed, 0 insertions, 0 deletions