Em Wed, Sep 07, 2022 at 11:37:50PM -0700, Namhyung Kim escreveu: > Hello, > > I found that call stack from the lock tracepoint (using bpf_get_stackid) > can be different on each configuration. For example it's very different > when I run it on a VM than on a real machine. > > The perf lock contention relies on the stack trace to get the lock > caller names, this kind of difference can be annoying. Ideally we could > skip stack trace entries for internal BPF or lock functions and get the > correct caller, but it's not the case as of today. Currently it's hard > coded to control the behavior of stack traces for the lock contention > tracepoints. > > To handle those differences, add two new options to control the number of > stack entries and how many it skips. The default value worked well on > my VM setup, but I had to use --stack-skip=5 on real machines. > > You can get it from 'perf/lock-stack-v1' branch in > > git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git This clashed with a patch you Acked earlier, so lets see if someone has extra review comments and a v2 become needed for other reason, when you can refresh it, ok? - Arnaldo > Thanks, > Namhyung > > > Namhyung Kim (4): > perf lock contention: Factor out get_symbol_name_offset() > perf lock contention: Show full callstack with -v option > perf lock contention: Allow to change stack depth and skip > perf lock contention: Skip stack trace from BPF > > tools/perf/Documentation/perf-lock.txt | 6 ++ > tools/perf/builtin-lock.c | 89 ++++++++++++++----- > tools/perf/util/bpf_lock_contention.c | 21 +++-- > .../perf/util/bpf_skel/lock_contention.bpf.c | 3 +- > tools/perf/util/lock-contention.h | 3 + > 5 files changed, 96 insertions(+), 26 deletions(-) > > > base-commit: 6c3bd8d3e01d9014312caa52e4ef1c29d5249648 > -- > 2.37.2.789.g6183377224-goog -- - Arnaldo
