On May 10, 2020 12:23:36 PM GMT-03:00, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: >On Sun, 10 May 2020 23:06:09 +0800 >Changbin Du <changbin.du@xxxxxxxxx> wrote: > >> The perf has basic kernel ftrace support but lack support of most >tracing >> options. This serias is target to enhance the perf ftrace >functionality so >> that we can make full use of kernel ftrace with only perf. >> >> In general, this serias be cataloged into two main changes: >> 1) Improve usability of existing functions. For example, we don't >need to type >> extra option to select the tracer. >> 2) Add new options to support all other ftrace functions. >> >> Here is a glance of all ftrace functions with this serias: >> * - improved existing options. >> + - new added options. >> >> $ sudo perf ftrace -h >> >> Usage: perf ftrace [<options>] [<command>] >> or: perf ftrace [<options>] -- <command> [<options>] >> >> * -a, --all-cpus system-wide collection from all CPUs >> + -b, --buffer-size <n> >> size of per cpu buffer in kb >> -C, --cpu <cpu> list of cpus to monitor >> + -d, --delay <n> Wait <n> ms before tracing >> -D, --graph-depth <n> >> Max depth for function graph tracer >> * -G, --graph-funcs <func> >> Set graph filter on given functions (imply >to use function_graph tracer) >> -g, --nograph-funcs <func> >> Set nograph filter on given functions >(imply to use function_graph tracer) >> + -L, --list-functions List available functions to filter >> + -l, --long-info Show process names, PIDs, timestamps, >irq-info if available >> -N, --notrace-funcs <func> >> do not trace given functions >> + -P, --no-pager Do not use pager >> -p, --pid <pid> trace on existing process id >> + -s, --func-stack-trace >> Show kernel stack trace for function tracer >> + -t, --tid <tid> trace on existing thread id (exclusive to >--pid) >> -T, --trace-funcs <func> >> trace given functions only >> + -u, --userstacktrace Show stacktrace of the current user space >thread >> -v, --verbose be more verbose >> + --funcgraph-tail Show function tails comment (function_graph >only) >> + --latency-format displays additional information about the >latency (function_graph only) >> + --nofuncgraph-irqs >> Ignore functions that happen inside >interrupt (function_graph only) >> + --nosleep-time Measure on-CPU time only (function_graph >only) >> + --trace-children Trace children processes >> + --tracing-thresh <n> >> Only show functions of which the duration >is greater than <n>µs >> > >Note, we are working on making more of the trace-cmd functionality into >libraries. See this work here: > >https://lore.kernel.org/r/20191219113502.28964-2-tz.stoyanov@xxxxxxxxx > >Which introduces a libtracefs, that is to handle all the work needed to >interact with the tracefs directory. This will also be useful for perf >to read the event directory without having to open code that work. > >I'm all for giving perf the functionality of ftrace, but I would like >to have it do so with a more generic solution that other tools could >benefit from as well. > I think in time things will fall into place, 'perf ftrace' has potential as a way for perf users to have a familiar interface to ftrace, and that I think it's its raison d'être, in time well go on finding ways to have common code. Tomorrow I'll go over this patch set, Thanks, - Arnaldo >Thanks! > >-- Steve -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
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