Skip to content
Commit cc336186 authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Add Intel PT support for decoding CYC packets



CYC packets provide even finer grain timestamp information than MTC and
TSC packets.  A CYC packet contains the number of CPU cycles since the
last CYC packet.

This patch just adds decoder support.  The CPU frequency can be related
to TSC using the Maximum Non-Turbo Ratio in combination with the CBR
(core-to-bus ratio) packet.  However more accuracy is achieved by simply
interpolating the number of cycles between other timing packets like MTC
or TSC.  This patch takes the latter approach.

Support for a default value and validation of values is provided by a
later patch. Also documentation is updated in a separate patch.

For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-23-git-send-email-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent b45fc0bf
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment