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SubjectRe: [PATCH 03/15 V3] perf c2c: Shared data analyser
On Tue, Apr 08, 2014 at 03:59:15PM +0900, Namhyung Kim wrote:
> Hi Don,

Oh by the way, thank you for your review. I will clean up a bunch of
stuff based on your suggestions.

Cheers,
Don

>
> On Mon, 24 Mar 2014 15:36:54 -0400, Don Zickus wrote:
> > From: Arnaldo Carvalho de Melo <acme@redhat.com>
> >
> > This is the start of a new perf tool that will collect information about
> > memory accesses and analyse it to find things like hot cachelines, etc.
>
> So why not integrating this into existing 'perf mem' command if it's all
> about analyzing memory accesses?
>
> >
> > This is basically trying to get a prototype written by Richard Fowles
> > written using the tools/perf coding style and libraries.
> >
> > Start it from 'perf sched', this patch starts the process by adding the
> > 'record' subcommand to collect the needed mem loads and stores samples.
> >
> > It also have the basic 'report' skeleton, resolving the sample address
> > and hooking the events found in a perf.data file with methods to handle
> > them, right now just printing the resolved perf_sample data structure
> > after each event name.
> >
> > [dcz: refreshed to latest upstream changes]
>
> [SNIP]
> > +perf-c2c(1)
> > +===========
> > +
> > +NAME
> > +----
> > +perf-c2c - Shared Data C2C/HITM Analyzer.
> > +
> > +SYNOPSIS
> > +--------
> > +[verse]
> > +'perf c2c' record
> > +
> > +DESCRIPTION
> > +-----------
> > +These are the variants of perf c2c:
> > +
> > + 'perf c2c record <command>' to record the memory accesses of an arbitrary
> > + workload.
> > +
> > +SEE ALSO
> > +--------
> > +linkperf:perf-record[1], linkperf:perf-mem[1]
>
> This document is very terse and only memtions the 'record' subcommand -
> also it's not updated throughout the series. So I'd like to suggest
> adding a separate documentation patch with full/verbose descriptions at
> the end of this series.
>
>
> [SNIP]
> > +static int perf_c2c__read_events(struct perf_c2c *c2c)
> > +{
> > + int err = -1;
> > + struct perf_session *session;
> > + struct perf_data_file file = {
> > + .path = input_name,
> > + .mode = PERF_DATA_MODE_READ,
> > + };
> > + struct perf_evsel *evsel;
> > +
> > + session = perf_session__new(&file, 0, &c2c->tool);
> > + if (session == NULL) {
> > + pr_debug("No memory for session\n");
> > + goto out;
> > + }
> > +
> > + /* setup the evsel handlers for each event type */
> > + evlist__for_each(session->evlist, evsel) {
> > + const char *name = perf_evsel__name(evsel);
> > + unsigned int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(handlers); i++) {
> > + if (!strcmp(name, handlers[i].name))
> > + evsel->handler = handlers[i].handler;
> > + }
> > + }
> > +
> > + err = perf_session__process_events(session, &c2c->tool);
> > + if (err)
> > + pr_err("Failed to process events, error %d", err);
>
> You may want to add perf_session__delete() here.
>
> > +
> > +out:
> > + return err;
> > +}
>
>
> [SNIP]
> > +int cmd_c2c(int argc, const char **argv, const char *prefix __maybe_unused)
> > +{
> > + struct perf_c2c c2c = {
> > + .tool = {
> > + .sample = perf_c2c__process_sample,
> > + .comm = perf_event__process_comm,
> > + .exit = perf_event__process_exit,
> > + .fork = perf_event__process_fork,
> > + .lost = perf_event__process_lost,
>
> It seems that it also needs to handle mmap[2] events otherwise it cannot
> find symbols from an address.
>
> Thanks,
> Namhyung
>
>
> > + .ordered_samples = true,
> > + },
> > + };


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