This patch series is to address the issue for synthesizing instruction samples, especially when the instruction sample period is small enough, the current logic cannot synthesize multiple instruction samples within one instruction range packet.
To fix this issue, patch 0001 avoids to reset the last branches for every instruction sample; if reset the last branches when every time generate instruction sample, then the later samples in the same range packet cannot use the last branches anymore.
Patch 0002 is the main patch to fix the logic for synthesizing instruction samples; it allows to handle different instruction periods.
Patch 0003 is an optimization for copying last branches; it only copies last branches once if the instruction samples share the same last branches.
Patch 0004 is a minor fix for unsigned variable comparison to zero.
To verify my changing for synthesizing instruction samples, I added some logs in the code, and reviewed the output log manually for instuctions samples. The below commands are tested on DB410c board:
# perf script --itrace=i2 # perf script --itrace=i2il16 # perf inject --itrace=i2il16 -i perf.data -o perf.data.new # perf inject --itrace=i100il16 -i perf.data -o perf.data.new
Changes from v1: * Rebased patch set on perf/core branch with latest commit 9fec3cd5fa4a ("perf map: Check if the map still has some refcounts on exit").
Leo Yan (4): perf cs-etm: Continuously record last branches perf cs-etm: Correct synthesizing instruction samples perf cs-etm: Optimize copying last branches perf cs-etm: Fix unsigned variable comparison to zero
tools/perf/util/cs-etm.c | 137 ++++++++++++++++++++++++++++++++------- 1 file changed, 115 insertions(+), 22 deletions(-)