Messages in this thread | | | Subject | Re: [PATCH v1 02/14] perf util: Create streams for managing top N hottest callchains | From | "Jin, Yao" <> | Date | Wed, 11 Mar 2020 13:38:37 +0800 |
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On 3/10/2020 11:11 PM, Arnaldo Carvalho de Melo wrote: > Em Tue, Mar 10, 2020 at 03:02:33PM +0800, Jin Yao escreveu: >> We think the stream is a callchain which is aggregated by the LBR >> records from samples. By browsing the stream, we can understand >> the code flow. >> >> The struct callchain_node represents one callchain and we use the >> callchain_node->hit to measure the hot level of this callchain. >> Higher is hotter. >> >> Since in perf data file, there may be many callchains so we just >> need to focus on the top N hottest callchains. N is a user defined >> parameter or just a predefined default value. >> >> This patch saves the top N hottest callchains in 'struct stream_node' >> type array, which is defined in a per event 'struct callchain_streams'. >> >> So now we can get the per-event top N hottest callchains. >> >> Signed-off-by: Jin Yao <yao.jin@linux.intel.com> >> --- >> tools/perf/util/callchain.c | 125 ++++++++++++++++++++++++++++++++++++ >> tools/perf/util/callchain.h | 16 +++++ >> 2 files changed, 141 insertions(+) >> >> diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c >> index 818aa4efd386..d9c68a8e7619 100644 >> --- a/tools/perf/util/callchain.c >> +++ b/tools/perf/util/callchain.c >> @@ -31,6 +31,7 @@ >> #include "callchain.h" >> #include "branch.h" >> #include "symbol.h" >> +#include "evlist.h" >> #include "../perf.h" >> >> #define CALLCHAIN_PARAM_DEFAULT \ >> @@ -1599,3 +1600,127 @@ void callchain_cursor_reset(struct callchain_cursor *cursor) >> for (node = cursor->first; node != NULL; node = node->next) >> map__zput(node->ms.map); >> } >> + >> +static void free_evsel_streams(struct callchain_streams *callchain_streams, >> + int nr_evsel) >> +{ >> + for (int i = 0; i < nr_evsel; i++) { >> + if (callchain_streams[i].streams) >> + free(callchain_streams[i].streams); > > free(NULL) is valid, so remove that extra check and use zfree() to reset > that entry to NULL, i.e.: > > for () > zfree(&callchain_streams[i].streams); >
Yes, will use zfree() here.
>> + } >> + >> + free(callchain_streams); >> +} >> + >> +static struct callchain_streams *create_evsel_streams(int nr_evsel, >> + int nr_streams_max) >> +{ >> + struct callchain_streams *callchain_streams; >> + >> + callchain_streams = calloc(nr_evsel, sizeof(struct callchain_streams)); > > calloc is the right thing here, as this is an array >
Yes. If just allocation for one element, I should use zalloc().
Thanks Jin Yao
>> + if (!callchain_streams) >> + return NULL; >> + >> + for (int i = 0; i < nr_evsel; i++) { >> + struct callchain_streams *s = &callchain_streams[i]; >> + >> + s->streams = calloc(nr_streams_max, sizeof(struct stream_node)); >> + if (!s->streams) >> + goto err; >> + >> + s->nr_streams_max = nr_streams_max; >> + s->evsel_idx = -1; >> + } >> + >> + return callchain_streams; >> + >> +err: >> + free_evsel_streams(callchain_streams, nr_evsel); >> + return NULL; >> +} >> + >> +/* >> + * The cnodes with high hit number are hot callchains. >> + */ >> +static void set_hot_cnode(struct callchain_streams *s, >> + struct callchain_node *cnode) >> +{ >> + int i, idx = 0; >> + u64 hit; >> + >> + if (s->nr_streams < s->nr_streams_max) { >> + i = s->nr_streams; >> + s->streams[i].cnode = cnode; >> + s->nr_streams++; >> + return; >> + } >> + >> + /* >> + * Since only a few number of hot streams, so only use simple >> + * way to find the cnode with smallest hit number and replace. >> + */ >> + hit = (s->streams[0].cnode)->hit; >> + for (i = 1; i < s->nr_streams; i++) { >> + if ((s->streams[i].cnode)->hit < hit) { >> + hit = (s->streams[i].cnode)->hit; >> + idx = i; >> + } >> + } >> + >> + if (cnode->hit > hit) >> + s->streams[idx].cnode = cnode; >> +} >> + >> +static void update_hot_streams(struct hist_entry *he, >> + struct callchain_streams *s) >> +{ >> + struct rb_root *root = &he->sorted_chain; >> + struct rb_node *rb_node = rb_first(root); >> + struct callchain_node *node; >> + >> + while (rb_node) { >> + node = rb_entry(rb_node, struct callchain_node, rb_node); >> + set_hot_cnode(s, node); >> + rb_node = rb_next(rb_node); >> + } >> +} >> + >> +static void get_hot_streams(struct hists *hists, >> + struct callchain_streams *s) >> +{ >> + struct rb_node *next; >> + >> + next = rb_first_cached(&hists->entries); >> + while (next) { >> + struct hist_entry *he; >> + >> + he = rb_entry(next, struct hist_entry, rb_node); >> + update_hot_streams(he, s); >> + next = rb_next(&he->rb_node); >> + } >> +} >> + >> +struct callchain_streams *callchain_evsel_streams_create(struct evlist *evlist, >> + int nr_streams_max, >> + int *nr_evsel_streams) >> +{ >> + int nr_evsel = evlist->core.nr_entries, i = 0; >> + struct callchain_streams *callchain_streams; >> + struct evsel *pos; >> + >> + callchain_streams = create_evsel_streams(nr_evsel, nr_streams_max); >> + if (!callchain_streams) >> + return NULL; >> + >> + evlist__for_each_entry(evlist, pos) { >> + struct hists *hists = evsel__hists(pos); >> + >> + hists__output_resort(hists, NULL); >> + get_hot_streams(hists, &callchain_streams[i]); >> + callchain_streams[i].evsel_idx = pos->idx; >> + i++; >> + } >> + >> + *nr_evsel_streams = nr_evsel; >> + return callchain_streams; >> +} >> diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h >> index 706bb7bbe1e1..5852990cdf60 100644 >> --- a/tools/perf/util/callchain.h >> +++ b/tools/perf/util/callchain.h >> @@ -13,6 +13,7 @@ struct ip_callchain; >> struct map; >> struct perf_sample; >> struct thread; >> +struct evlist; >> >> #define HELP_PAD "\t\t\t\t" >> >> @@ -159,6 +160,17 @@ struct callchain_cursor { >> struct callchain_cursor_node *curr; >> }; >> >> +struct stream_node { >> + struct callchain_node *cnode; >> +}; >> + >> +struct callchain_streams { >> + struct stream_node *streams; >> + int nr_streams_max; >> + int nr_streams; >> + int evsel_idx; >> +}; >> + >> extern __thread struct callchain_cursor callchain_cursor; >> >> static inline void callchain_init(struct callchain_root *root) >> @@ -289,4 +301,8 @@ int callchain_branch_counts(struct callchain_root *root, >> u64 *branch_count, u64 *predicted_count, >> u64 *abort_count, u64 *cycles_count); >> >> +struct callchain_streams *callchain_evsel_streams_create(struct evlist *evlist, >> + int nr_streams_max, >> + int *nr_evsel_streams); >> + >> #endif /* __PERF_CALLCHAIN_H */ >> -- >> 2.17.1 >> >
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