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authorPeter Zijlstra <peterz@infradead.org>2018-11-20 18:08:42 +0100
committerIngo Molnar <mingo@kernel.org>2018-11-20 18:57:48 +0100
commit2a5bf23d5b795d5df33dc284e8f5cf8b6a5b4042 (patch)
treea8e7207d6415cc41b8458be461909c05abf0062c /Documentation
parent9ff01193a20d391e8dbce4403dd5ef87c7eaaca6 (diff)
downloadlinux-2a5bf23d5b795d5df33dc284e8f5cf8b6a5b4042.tar.bz2
perf/x86/intel: Fix regression by default disabling perfmon v4 interrupt handling
Kyle Huey reported that 'rr', a replay debugger, broke due to the following commit: af3bdb991a5c ("perf/x86/intel: Add a separate Arch Perfmon v4 PMI handler") Rework the 'disable_counter_freezing' __setup() parameter such that we can explicitly enable/disable it and switch to default disabled. To this purpose, rename the parameter to "perf_v4_pmi=" which is a much better description and allows requiring a bool argument. [ mingo: Improved the changelog some more. ] Reported-by: Kyle Huey <me@kylehuey.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert O'Callahan <robert@ocallahan.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: acme@kernel.org Link: http://lkml.kernel.org/r/20181120170842.GZ2131@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt3
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 81d1d5a74728..5463d5a4d85c 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -856,7 +856,8 @@
causing system reset or hang due to sending
INIT from AP to BSP.
- disable_counter_freezing [HW]
+ perf_v4_pmi= [X86,INTEL]
+ Format: <bool>
Disable Intel PMU counter freezing feature.
The feature only exists starting from
Arch Perfmon v4 (Skylake and newer).