[tip:perf/core] perf trace: Add support for pagefault tracing

From: tip-bot for Stanislav Fomichev
Date: Sat Jul 05 2014 - 06:41:43 EST

Next message: tip-bot for Stanislav Fomichev: "[tip:perf/core] perf trace: Add pagefaults record and replay support"
Previous message: tip-bot for Daniel Bristot de Oliveira: "[tip:perf/core] perf scripts: Fallback to syscalls: * when raw_syscalls:* is not available"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Commit-ID: 598d02c5a07b60e5c824184cdaf697b70f3c452a
Gitweb: http://git.kernel.org/tip/598d02c5a07b60e5c824184cdaf697b70f3c452a
Author: Stanislav Fomichev <stfomichev@xxxxxxxxxxxxxx>
AuthorDate: Thu, 26 Jun 2014 20:14:25 +0400
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 26 Jun 2014 16:07:43 -0300

perf trace: Add support for pagefault tracing

This patch adds optional pagefault tracing support to 'perf trace'.

Using -F/--pf option user can specify whether he wants minor, major or
all pagefault events to be traced. This patch adds only live mode,
record and replace will come in a separate patch.

Example output:

1756272.905 ( 0.000 ms): curl/5937 majfault [0x7fa7261978b6] => /usr/lib/x86_64-linux-gnu/libkrb5.so.26.0.0@0x85288 (d.)
1862866.036 ( 0.000 ms): wget/8460 majfault [__clear_user+0x3f] => 0x659cb4 (?k)

Signed-off-by: Stanislav Fomichev <stfomichev@xxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1403799268-1367-3-git-send-email-stfomichev@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/Documentation/perf-trace.txt | 39 ++++++++++
tools/perf/builtin-trace.c | 125 +++++++++++++++++++++++++++++++-
2 files changed, 163 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt
index fae38d9..72397d9 100644
--- a/tools/perf/Documentation/perf-trace.txt
+++ b/tools/perf/Documentation/perf-trace.txt
@@ -107,6 +107,45 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs.
Show tool stats such as number of times fd->pathname was discovered thru
hooking the open syscall return + vfs_getname or via reading /proc/pid/fd, etc.

+-F=[all|min|maj]::
+--pf=[all|min|maj]::
+ Trace pagefaults. Optionally, you can specify whether you want minor,
+ major or all pagefaults. Default value is maj.
+
+PAGEFAULTS
+----------
+
+When tracing pagefaults, the format of the trace is as follows:
+
+<min|maj>fault [<ip.symbol>+<ip.offset>] => <addr.dso@xxxxxxxxxxx> (<map type><addr level>).
+
+- min/maj indicates whether fault event is minor or major;
+- ip.symbol shows symbol for instruction pointer (the code that generated the
+ fault); if no debug symbols available, perf trace will print raw IP;
+- addr.dso shows DSO for the faulted address;
+- map type is either 'd' for non-executable maps or 'x' for executable maps;
+- addr level is either 'k' for kernel dso or '.' for user dso.
+
+For symbols resolution you may need to install debugging symbols.
+
+Please be aware that duration is currently always 0 and doesn't reflect actual
+time it took for fault to be handled!
+
+When --verbose specified, perf trace tries to print all available information
+for both IP and fault address in the form of dso@symbol+offset.
+
+EXAMPLES
+--------
+
+Trace syscalls, major and minor pagefaults:
+
+ $ perf trace -F all
+
+ 1416.547 ( 0.000 ms): python/20235 majfault [CRYPTO_push_info_+0x0] => /lib/x86_64-linux-gnu/libcrypto.so.1.0.0@0x61be0 (x.)
+
+ As you can see, there was major pagefault in python process, from
+ CRYPTO_push_info_ routine which faulted somewhere in libcrypto.so.
+
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-script[1]
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 4a9e26b..1985c3b 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1178,6 +1178,9 @@ fail:
return NULL;
}

+#define TRACE_PFMAJ (1 << 0)
+#define TRACE_PFMIN (1 << 1)
+
struct trace {
struct perf_tool tool;
struct {
@@ -1212,6 +1215,7 @@ struct trace {
bool summary_only;
bool show_comm;
bool show_tool_stats;
+ int trace_pgfaults;
};

static int trace__set_fd_pathname(struct thread *thread, int fd, const char *pathname)
@@ -1773,6 +1777,68 @@ out_dump:
return 0;
}

+static void print_location(FILE *f, struct perf_sample *sample,
+ struct addr_location *al,
+ bool print_dso, bool print_sym)
+{
+
+ if ((verbose || print_dso) && al->map)
+ fprintf(f, "%s@", al->map->dso->long_name);
+
+ if ((verbose || print_sym) && al->sym)
+ fprintf(f, "%s+0x%lx", al->sym->name,
+ al->addr - al->sym->start);
+ else if (al->map)
+ fprintf(f, "0x%lx", al->addr);
+ else
+ fprintf(f, "0x%lx", sample->addr);
+}
+
+static int trace__pgfault(struct trace *trace,
+ struct perf_evsel *evsel,
+ union perf_event *event,
+ struct perf_sample *sample)
+{
+ struct thread *thread;
+ u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+ struct addr_location al;
+ char map_type = 'd';
+
+ thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);
+
+ thread__find_addr_location(thread, trace->host, cpumode, MAP__FUNCTION,
+ sample->ip, &al);
+
+ trace__fprintf_entry_head(trace, thread, 0, sample->time, trace->output);
+
+ fprintf(trace->output, "%sfault [",
+ evsel->attr.config == PERF_COUNT_SW_PAGE_FAULTS_MAJ ?
+ "maj" : "min");
+
+ print_location(trace->output, sample, &al, false, true);
+
+ fprintf(trace->output, "] => ");
+
+ thread__find_addr_location(thread, trace->host, cpumode, MAP__VARIABLE,
+ sample->addr, &al);
+
+ if (!al.map) {
+ thread__find_addr_location(thread, trace->host, cpumode,
+ MAP__FUNCTION, sample->addr, &al);
+
+ if (al.map)
+ map_type = 'x';
+ else
+ map_type = '?';
+ }
+
+ print_location(trace->output, sample, &al, true, false);
+
+ fprintf(trace->output, " (%c%c)\n", map_type, al.level);
+
+ return 0;
+}
+
static bool skip_sample(struct trace *trace, struct perf_sample *sample)
{
if ((trace->pid_list && intlist__find(trace->pid_list, sample->pid)) ||
@@ -1887,6 +1953,30 @@ static void perf_evlist__add_vfs_getname(struct perf_evlist *evlist)
perf_evlist__add(evlist, evsel);
}

+static int perf_evlist__add_pgfault(struct perf_evlist *evlist,
+ u64 config)
+{
+ struct perf_evsel *evsel;
+ struct perf_event_attr attr = {
+ .type = PERF_TYPE_SOFTWARE,
+ .mmap_data = 1,
+ .sample_period = 1,
+ };
+
+ attr.config = config;
+
+ event_attr_init(&attr);
+
+ evsel = perf_evsel__new(&attr);
+ if (!evsel)
+ return -ENOMEM;
+
+ evsel->handler = trace__pgfault;
+ perf_evlist__add(evlist, evsel);
+
+ return 0;
+}
+
static int trace__run(struct trace *trace, int argc, const char **argv)
{
struct perf_evlist *evlist = perf_evlist__new();
@@ -1907,6 +1997,14 @@ static int trace__run(struct trace *trace, int argc, const char **argv)

perf_evlist__add_vfs_getname(evlist);

+ if ((trace->trace_pgfaults & TRACE_PFMAJ) &&
+ perf_evlist__add_pgfault(evlist, PERF_COUNT_SW_PAGE_FAULTS_MAJ))
+ goto out_error_tp;
+
+ if ((trace->trace_pgfaults & TRACE_PFMIN) &&
+ perf_evlist__add_pgfault(evlist, PERF_COUNT_SW_PAGE_FAULTS_MIN))
+ goto out_error_tp;
+
if (trace->sched &&
perf_evlist__add_newtp(evlist, "sched", "sched_stat_runtime",
trace__sched_stat_runtime))
@@ -1987,7 +2085,8 @@ again:
goto next_event;
}

- if (sample.raw_data == NULL) {
+ if (evsel->attr.type == PERF_TYPE_TRACEPOINT &&
+ sample.raw_data == NULL) {
fprintf(trace->output, "%s sample with no payload for tid: %d, cpu %d, raw_size=%d, skipping...\n",
perf_evsel__name(evsel), sample.tid,
sample.cpu, sample.raw_size);
@@ -2269,6 +2368,23 @@ static int trace__open_output(struct trace *trace, const char *filename)
return trace->output == NULL ? -errno : 0;
}

+static int parse_pagefaults(const struct option *opt, const char *str,
+ int unset __maybe_unused)
+{
+ int *trace_pgfaults = opt->value;
+
+ if (strcmp(str, "all") == 0)
+ *trace_pgfaults |= TRACE_PFMAJ | TRACE_PFMIN;
+ else if (strcmp(str, "maj") == 0)
+ *trace_pgfaults |= TRACE_PFMAJ;
+ else if (strcmp(str, "min") == 0)
+ *trace_pgfaults |= TRACE_PFMIN;
+ else
+ return -1;
+
+ return 0;
+}
+
int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
{
const char * const trace_usage[] = {
@@ -2335,6 +2451,8 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
"Show only syscall summary with statistics"),
OPT_BOOLEAN('S', "with-summary", &trace.summary,
"Show all syscalls and summary with statistics"),
+ OPT_CALLBACK_DEFAULT('F', "pf", &trace.trace_pgfaults, "all|maj|min",
+ "Trace pagefaults", parse_pagefaults, "maj"),
OPT_END()
};
int err;
@@ -2349,6 +2467,11 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
if (trace.summary_only)
trace.summary = trace.summary_only;

+ if (trace.trace_pgfaults) {
+ trace.opts.sample_address = true;
+ trace.opts.sample_time = true;
+ }
+
if (output_name != NULL) {
err = trace__open_output(&trace, output_name);
if (err < 0) {
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: tip-bot for Stanislav Fomichev: "[tip:perf/core] perf trace: Add pagefaults record and replay support"
Previous message: tip-bot for Daniel Bristot de Oliveira: "[tip:perf/core] perf scripts: Fallback to syscalls: * when raw_syscalls:* is not available"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]