From: Andi Kleen <andi@firstfloor.org>
To: peterz@infradead.org
Cc: acme@kernel.org, linux-kernel@vger.kernel.org, jolsa@redhat.com,
eranian@google.com
Subject:
Date: Wed, 27 May 2015 21:13:13 -0700 [thread overview]
Message-ID: <1432786398-23861-1-git-send-email-andi@firstfloor.org> (raw)
[Repost; I forgot to copy linux-kernel earlier. Apologies if you
see it twice.]
Skylake moved to 32 Last Branch Records, from previously 16.
The current call stack LBR implementation reads all LBRs and
also saves/restores them on context switch. This patchkit
adds some optimizations to avoid extra costs in most cases
from the larger number of LBRs for call-stack, unless a nesting
larger than 16 is actually needed. It applies on top of the
earlier Skylake code. Some of the optimization will also benefit
earlier CPUs, such as Haswell.
note: one patch is for perf user space, the rest is kernel.
-Andi
next reply other threads:[~2015-05-28 4:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-28 4:13 Andi Kleen [this message]
2015-05-28 4:13 ` [PATCH 1/5] x86, perf: Allow time stamp for free running PEBSv3 Andi Kleen
2015-08-04 8:56 ` [tip:perf/core] perf/x86/intel/lbr: " tip-bot for Andi Kleen
2015-05-28 4:13 ` [PATCH 2/5] x86, perf: Add option to disable reading branch flags/cycles Andi Kleen
2015-06-15 10:48 ` Peter Zijlstra
2015-05-28 4:13 ` [PATCH 3/5] perf, tools: Disable branch flags/cycles for lbr call graph Andi Kleen
2015-05-28 4:13 ` [PATCH 4/5] x86, perf: Use correct index to save/restore LBR_INFO with callstack Andi Kleen
2015-08-04 8:59 ` [tip:perf/core] perf/x86/intel/lbr: Use correct index to save/ restore LBR_INFO with call stack tip-bot for Andi Kleen
2015-05-28 4:13 ` [PATCH 5/5] x86, perf: Limit LBR accesses to TOS in callstack mode Andi Kleen
2015-08-04 8:59 ` [tip:perf/core] perf/x86/intel/lbr: " tip-bot for Andi Kleen
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