Re: [tip:perfcounters/core] perf record/report: Add call graph / call chain profiling

Frederic Weisbecker
2009-06-16T02:58:09Z

On Sun, Jun 14, 2009 at 06:36:32PM +0000, tip-bot for Ingo Molnar wrote:
> Commit-ID: 3efa1cc99ec51bc7a7ae0011a16619fd20dbe6ea
> Gitweb: http://git.kernel.org/tip/3efa1cc99ec51bc7a7ae0011a16619fd20dbe6ea
> Author: Ingo Molnar <mingo@elte.hu>
> AuthorDate: Sun, 14 Jun 2009 15:04:15 +0200
> Committer: Ingo Molnar <mingo@elte.hu>
> CommitDate: Sun, 14 Jun 2009 20:34:06 +0200
>
> perf record/report: Add call graph / call chain profiling
>
> Add the first steps of call-graph profiling:
>
> - add the -c (--call-graph) option to perf record
> - parse the call-graph record and printout out under -D (--dump-trace)
>
> The call-graph data is not put into the histogram yet, but it
> can be seen that it's being processed correctly:
>
> 0x3ce0 [0x38]: event: 35
> .
> . ... raw event: size 56 bytes
> . 0000: 23 00 00 00 05 00 38 00 d4 df 0e 81 ff ff ff ff #.....8........
> . 0010: 60 0b 00 00 60 0b 00 00 03 00 00 00 01 00 02 00 `...`..........
> . 0020: d4 df 0e 81 ff ff ff ff a0 61 ed 41 36 00 00 00 .........a.A6..
> . 0030: 04 92 e6 41 36 00 00 00 .a.A6..
> .
> 0x3ce0 [0x38]: PERF_EVENT (IP, 5): 2912: 0xffffffff810edfd4 period: 1
> ... chain: u:2, k:1, nr:3
> ..... 0: 0xffffffff810edfd4
> ..... 1: 0x3641ed61a0
> ..... 2: 0x3641e69204
> ... thread: perf:2912
> ...... dso: [kernel]
>
> This shows a 3-entry call-graph: with 1 kernel-space and two user-space
> entries
>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Pekka Enberg <penberg@cs.helsinki.fi>
> Cc: Arjan van de Ven <arjan@infradead.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> LKML-Reference: <new-submission>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
>
>
> ---
> tools/perf/builtin-record.c | 8 ++++++
> tools/perf/builtin-report.c | 57 ++++++++++++++++++++++++++++++++++---------
> 2 files changed, 53 insertions(+), 12 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 0f5771f..a177a59 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -37,6 +37,7 @@ static pid_t target_pid = -1;
> static int inherit = 1;
> static int force = 0;
> static int append_file = 0;
> +static int call_graph = 0;
> static int verbose = 0;
>
> static long samples;
> @@ -351,11 +352,16 @@ static void create_counter(int counter, int cpu, pid_t pid)
> int track = 1;
>
> attr->sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
> +
> if (freq) {
> attr->sample_type |= PERF_SAMPLE_PERIOD;
> attr->freq = 1;
> attr->sample_freq = freq;
> }
> +
> + if (call_graph)
> + attr->sample_type |= PERF_SAMPLE_CALLCHAIN;
> +
> attr->mmap = track;
> attr->comm = track;
> attr->inherit = (cpu < 0) && inherit;
> @@ -555,6 +561,8 @@ static const struct option options[] = {
> "profile at this frequency"),
> OPT_INTEGER('m', "mmap-pages", &mmap_pages,
> "number of mmap data pages"),
> + OPT_BOOLEAN('g', "call-graph", &call_graph,
> + "do call-graph (stack chain/backtrace) recording"),
> OPT_BOOLEAN('v', "verbose", &verbose,
> "be more verbose (show counter open errors, etc)"),
> OPT_END()
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index 37515da..aebba56 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -36,6 +36,7 @@ static int show_mask = SHOW_KERNEL | SHOW_USER | SHOW_HV;
>
> static int dump_trace = 0;
> #define dprintf(x...) do { if (dump_trace) printf(x); } while (0)
> +#define cdprintf(x...) do { if (dump_trace) color_fprintf(stdout, color, x); } while (0)
>
> static int verbose;
> static int full_paths;
> @@ -43,11 +44,19 @@ static int full_paths;
> static unsigned long page_size;
> static unsigned long mmap_window = 32;
>
> +struct ip_chain_event {
> + __u16 nr;

Is it needed to have the nr encoded in the ip_chain?
We can already find it by doing kernel + user.

Thanks,
Frederic.

> + __u16 hv;
> + __u16 kernel;
> + __u16 user;
> + __u64 ips[];
> +};
> +
> struct ip_event {
> struct perf_event_header header;
> __u64 ip;
> __u32 pid, tid;
> - __u64 period;
> + unsigned char __more_data[];
> };
>
> struct mmap_event {
> @@ -944,9 +953,13 @@ process_overflow_event(event_t *event, unsigned long offset, unsigned long head)
> __u64 ip = event->ip.ip;
> __u64 period = 1;
> struct map *map = NULL;
> + void *more_data = event->ip.__more_data;
> + struct ip_chain_event *chain;
>
> - if (event->header.type & PERF_SAMPLE_PERIOD)
> - period = event->ip.period;
> + if (event->header.type & PERF_SAMPLE_PERIOD) {
> + period = *(__u64 *)more_data;
> + more_data += sizeof(__u64);
> + }
>
> dprintf("%p [%p]: PERF_EVENT (IP, %d): %d: %p period: %Ld\n",
> (void *)(offset + head),
> @@ -956,6 +969,22 @@ process_overflow_event(event_t *event, unsigned long offset, unsigned long head)
> (void *)(long)ip,
> (long long)period);
>
> + if (event->header.type & PERF_SAMPLE_CALLCHAIN) {
> + int i;
> +
> + chain = (void *)more_data;
> +
> + if (dump_trace) {
> + dprintf("... chain: u:%d, k:%d, nr:%d\n",
> + chain->user,
> + chain->kernel,
> + chain->nr);
> +
> + for (i = 0; i < chain->nr; i++)
> + dprintf("..... %2d: %p\n", i, (void *)chain->ips[i]);
> + }
> + }
> +
> dprintf(" ... thread: %s:%d\n", thread->comm, thread->pid);
>
> if (thread == NULL) {
> @@ -1098,30 +1127,34 @@ process_period_event(event_t *event, unsigned long offset, unsigned long head)
> static void trace_event(event_t *event)
> {
> unsigned char *raw_event = (void *)event;
> + char *color = PERF_COLOR_BLUE;
> int i, j;
>
> if (!dump_trace)
> return;
>
> - dprintf(".\n. ... raw event: size %d bytes\n", event->header.size);
> + dprintf(".");
> + cdprintf("\n. ... raw event: size %d bytes\n", event->header.size);
>
> for (i = 0; i < event->header.size; i++) {
> - if ((i & 15) == 0)
> - dprintf(". %04x: ", i);
> + if ((i & 15) == 0) {
> + dprintf(".");
> + cdprintf(" %04x: ", i);
> + }
>
> - dprintf(" %02x", raw_event[i]);
> + cdprintf(" %02x", raw_event[i]);
>
> if (((i & 15) == 15) || i == event->header.size-1) {
> - dprintf(" ");
> + cdprintf(" ");
> for (j = 0; j < 15-(i & 15); j++)
> - dprintf(" ");
> + cdprintf(" ");
> for (j = 0; j < (i & 15); j++) {
> if (isprint(raw_event[i-15+j]))
> - dprintf("%c", raw_event[i-15+j]);
> + cdprintf("%c", raw_event[i-15+j]);
> else
> - dprintf(".");
> + cdprintf(".");
> }
> - dprintf("\n");
> + cdprintf("\n");
> }
> }
> dprintf(".\n");