From: Markus Metzger <markus.t.metzger@intel.com>
Date: Tue, 15 Sep 2009 11:00:23 +0000 (+0200)
Subject: x86, perf_counter, bts: Optimize BTS overflow handling
X-Git-Tag: v2.6.32-rc1~628^2~16
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5622f295b53fb60dbf9bed3e2c89d182490a8b7f;p=pandora-kernel.git

x86, perf_counter, bts: Optimize BTS overflow handling

Draining the BTS buffer on a buffer overflow interrupt takes too
long resulting in a kernel lockup when tracing the kernel.

Restructure perf_counter sampling into sample creation and sample
output.

Prepare a single reference sample for BTS sampling and update the
from and to address fields when draining the BTS buffer. Drain the
entire BTS buffer between a single perf_output_begin() /
perf_output_end() pair.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090915130023.A16204@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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