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perf list: Document precise event sampling for AMD IBS 

Updating man perf-list.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1344361396-7237-7-git-send-email-robert.richter@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Robert Richter 2012-08-07 19:43:16 +02:00 committed by Arnaldo Carvalho de Melo
parent 75bc5ca898
commit 2055fdaf87
1 changed files with 30 additions and 12 deletions
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42
tools/perf/Documentation/perf-list.txt
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@ -20,20 +20,38 @@ EVENT MODIFIERS
---------------
Events can optionally have a modifer by appending a colon and one or
more modifiers. Modifiers allow the user to restrict when events are
counted with 'u' for user-space, 'k' for kernel, 'h' for hypervisor.
Additional modifiers are 'G' for guest counting (in KVM guests) and 'H'
for host counting (not in KVM guests).
more modifiers. Modifiers allow the user to restrict the events to be
counted. The following modifiers exist:
u - user-space counting
k - kernel counting
h - hypervisor counting
G - guest counting (in KVM guests)
H - host counting (not in KVM guests)
p - precise level
The 'p' modifier can be used for specifying how precise the instruction
address should be. The 'p' modifier is currently only implemented for
Intel PEBS and can be specified multiple times:
0 - SAMPLE_IP can have arbitrary skid
1 - SAMPLE_IP must have constant skid
2 - SAMPLE_IP requested to have 0 skid
3 - SAMPLE_IP must have 0 skid
address should be. The 'p' modifier can be specified multiple times:
The PEBS implementation now supports up to 2.
0 - SAMPLE_IP can have arbitrary skid
1 - SAMPLE_IP must have constant skid
2 - SAMPLE_IP requested to have 0 skid
3 - SAMPLE_IP must have 0 skid
For Intel systems precise event sampling is implemented with PEBS
which supports up to precise-level 2.
On AMD systems it is implemented using IBS (up to precise-level 2).
The precise modifier works with event types 0x76 (cpu-cycles, CPU
clocks not halted) and 0xC1 (micro-ops retired). Both events map to
IBS execution sampling (IBS op) with the IBS Op Counter Control bit
(IbsOpCntCtl) set respectively (see AMD64 Architecture Programmer’s
Manual Volume 2: System Programming, 13.3 Instruction-Based
Sampling). Examples to use IBS:
perf record -a -e cpu-cycles:p ... # use ibs op counting cycles
perf record -a -e r076:p ... # same as -e cpu-cycles:p
perf record -a -e r0C1:p ... # use ibs op counting micro-ops
RAW HARDWARE EVENT DESCRIPTOR
-----------------------------
@ -97,4 +115,4 @@ SEE ALSO
linkperf:perf-stat[1], linkperf:perf-top[1],
linkperf:perf-record[1],
http://www.intel.com/Assets/PDF/manual/253669.pdf[Intel® 64 and IA-32 Architectures Software Developer's Manual Volume 3B: System Programming Guide],
http://support.amd.com/us/Processor_TechDocs/24593.pdf[AMD64 Architecture Programmer’s Manual Volume 2: System Programming]
http://support.amd.com/us/Processor_TechDocs/24593_APM_v2.pdf[AMD64 Architecture Programmer’s Manual Volume 2: System Programming]