[GIT PULL 00/12] perf/core improvements and fixes

[GIT PULL 00/12] perf/core improvements and fixes

[Arnaldo Carvalho de Melo]

Hi Ingo,

	Please consider pulling,

- Arnaldo

The following changes since commit 4e6e311e596eadba30d4f56f64eae7d45611a01c:

  Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core (2014-11-20 08:32:01 +0100)

are available in the git repository at:


  git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tags/perf-core-for-mingo

for you to fetch changes up to 1d9e446b91e182055d874fbb30150aad479a4981:

  perf tools: Add snapshot format file parsing (2014-11-24 18:03:51 -0300)

----------------------------------------------------------------
perf/core improvements and fixes:

User visible:

- Callchain improvements from Andi Kleen including:
  * Enable printing the srcline in the history
  * Make get_srcline fall back to sym+offset

- Allow to force redirect pr_debug to stderr. (Andi Kleen)

- TUI hist_entry browser fixes, including showing missing overhead
  value for first level callchain. Detected comparing the output of
  --stdio/--gui (that matched) with --tui, that had this problem. (Namhyung Kim)

- Fix segfault due to invalid kernel dso access (Namhyung Kim)

Infrastructure:

- Move bfd_demangle stubbing to its only user (Arnaldo Carvalho de Melo)

- 'perf stat' refactorings, moving stuff from it to evsel.c to use in
  per-pkg/snapshot format changes (Jiri Olsa)

- Add per-pkg format file parsing (Matt Fleming)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

----------------------------------------------------------------
Andi Kleen (3):
      perf callchain: Enable printing the srcline in the history
      perf callchain: Make get_srcline fall back to sym+offset
      perf tools: Allow to force redirect pr_debug to stderr.

Arnaldo Carvalho de Melo (1):
      perf symbols: Move bfd_demangle stubbing to its only user

Jiri Olsa (4):
      perf evsel: Introduce perf_evsel__compute_deltas function
      perf evsel: Introduce perf_counts_values__scale function
      perf evsel: Introduce perf_evsel__read_cb function
      perf tools: Add snapshot format file parsing

Matt Fleming (1):
      perf tools: Add per-pkg format file parsing

Namhyung Kim (3):
      perf hists browser: Print overhead percent value for first-level callchain
      perf tools: Collapse first level callchain entry if it has sibling
      perf tools: Fix segfault due to invalid kernel dso access

 tools/perf/ui/browsers/hists.c | 25 +++++++++++---
 tools/perf/util/annotate.c     |  2 +-
 tools/perf/util/callchain.c    | 12 ++++++-
 tools/perf/util/callchain.h    |  1 +
 tools/perf/util/debug.c        |  4 ++-
 tools/perf/util/evsel.c        | 72 +++++++++++++++++++++++-----------------
 tools/perf/util/evsel.h        | 15 +++++++++
 tools/perf/util/machine.c      |  4 +--
 tools/perf/util/map.c          |  2 +-
 tools/perf/util/parse-events.c |  2 ++
 tools/perf/util/pmu.c          | 74 +++++++++++++++++++++++++++++++++++-------
 tools/perf/util/pmu.h          |  4 +++
 tools/perf/util/sort.c         |  6 ++--
 tools/perf/util/srcline.c      | 15 +++++++--
 tools/perf/util/symbol-elf.c   | 21 ++++++++++++
 tools/perf/util/symbol.h       | 21 ------------
 tools/perf/util/util.h         |  4 ++-
 17 files changed, 205 insertions(+), 79 deletions(-)

[PATCH 01/12] perf hists browser: Print overhead percent value for first-level callchain

[Arnaldo Carvalho de Melo]

From: Namhyung Kim <namhyung@kernel.org>

Currently perf report on TUI doesn't print percent for first-level
callchain entry.

I guess it (wrongly) assumes that there's only a single callchain in the
first level.

This patch fixes it by handling the first level callchains same as
others - if it's not 100% it should print the percent value.

Also it'll affect other callchains in the other way around - if it's
100% (single callchain) it should not print the percentage.

Before:
  -   30.95%     6.84%  abc2     abc2              [.] a
     - a
        - 70.00% c
           - 100.00% apic_timer_interrupt
                smp_apic_timer_interrupt
                local_apic_timer_interrupt
                hrtimer_interrupt
                ...
        + 30.00% b
     + __libc_start_main

After:
  -   30.95%     6.84%  abc2     abc2              [.] a
     - 77.90% a
        - 70.00% c
           - apic_timer_interrupt
             smp_apic_timer_interrupt
             local_apic_timer_interrupt
             hrtimer_interrupt
             ...
        + 30.00% b
     + 22.10% __libc_start_main

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1416816807-6495-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/ui/browsers/hists.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index 12c17c5a3d68..8d22905a4687 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -542,8 +542,11 @@ static int hist_browser__show_callchain(struct hist_browser *browser,
 	struct rb_node *node;
 	int first_row = row, offset = level * LEVEL_OFFSET_STEP;
 	u64 new_total;
+	bool need_percent;
 
 	node = rb_first(root);
+	need_percent = !!rb_next(node);
+
 	while (node) {
 		struct callchain_node *child = rb_entry(node, struct callchain_node, rb_node);
 		struct rb_node *next = rb_next(node);
@@ -560,7 +563,7 @@ static int hist_browser__show_callchain(struct hist_browser *browser,
 
 			if (first)
 				first = false;
-			else if (level > 1)
+			else if (need_percent)
 				extra_offset = LEVEL_OFFSET_STEP;
 
 			folded_sign = callchain_list__folded(chain);
@@ -573,7 +576,7 @@ static int hist_browser__show_callchain(struct hist_browser *browser,
 			str = callchain_list__sym_name(chain, bf, sizeof(bf),
 						       browser->show_dso);
 
-			if (was_first && level > 1) {
+			if (was_first && need_percent) {
 				double percent = cumul * 100.0 / total;
 
 				if (asprintf(&alloc_str, "%2.2f%% %s", percent, str) < 0)
@@ -790,6 +793,13 @@ static int hist_browser__show_entry(struct hist_browser *browser,
 			.is_current_entry = current_entry,
 		};
 
+		if (callchain_param.mode == CHAIN_GRAPH_REL) {
+			if (symbol_conf.cumulate_callchain)
+				total = entry->stat_acc->period;
+			else
+				total = entry->stat.period;
+		}
+
 		printed += hist_browser__show_callchain(browser,
 					&entry->sorted_chain, 1, row, total,
 					hist_browser__show_callchain_entry, &arg,
-- 
1.9.3

[PATCH 02/12] perf tools: Collapse first level callchain entry if it has sibling

[Arnaldo Carvalho de Melo]

From: Namhyung Kim <namhyung@kernel.org>

If first level callchain has more than single path like when -g caller
option is given, it should show only first one in the path and hide
others.  But it didn't do it properly and just hindered the output.

Before:
  -   80.33%    11.11%  abc2     abc2              [.] main
     + 86.18% main
       13.82% __libc_start_main
          main

After:
  -   80.33%    11.11%  abc2     abc2              [.] main
     + 86.18% main
     + 13.82% __libc_start_main

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1416816807-6495-2-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/ui/browsers/hists.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index 8d22905a4687..502daff76ceb 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -227,10 +227,14 @@ static void callchain_node__init_have_children_rb_tree(struct callchain_node *no
 	}
 }
 
-static void callchain_node__init_have_children(struct callchain_node *node)
+static void callchain_node__init_have_children(struct callchain_node *node,
+					       bool has_sibling)
 {
 	struct callchain_list *chain;
 
+	chain = list_entry(node->val.next, struct callchain_list, list);
+	chain->ms.has_children = has_sibling;
+
 	if (!list_empty(&node->val)) {
 		chain = list_entry(node->val.prev, struct callchain_list, list);
 		chain->ms.has_children = !RB_EMPTY_ROOT(&node->rb_root);
@@ -241,11 +245,12 @@ static void callchain_node__init_have_children(struct callchain_node *node)
 
 static void callchain__init_have_children(struct rb_root *root)
 {
-	struct rb_node *nd;
+	struct rb_node *nd = rb_first(root);
+	bool has_sibling = nd && rb_next(nd);
 
 	for (nd = rb_first(root); nd; nd = rb_next(nd)) {
 		struct callchain_node *node = rb_entry(nd, struct callchain_node, rb_node);
-		callchain_node__init_have_children(node);
+		callchain_node__init_have_children(node, has_sibling);
 	}
 }
 
-- 
1.9.3

[PATCH 03/12] perf callchain: Enable printing the srcline in the history

[Arnaldo Carvalho de Melo]

From: Andi Kleen <ak@linux.intel.com>

For lbr-as-callgraph we need to see the line number in the history,
because many LBR entries can be in a single function, and just
showing the same function name many times is not useful.

When the history code is configured to sort by address, also try to
resolve the address to a file:srcline and display this in the browser.
If that doesn't work still display the address.

This can be also useful without LBRs for understanding which call in a large
function (or in which inlined function) called something else.

Contains fixes from Namhyung Kim

v2: Refactor code into common function
v3: Fix GTK build
v4: Rebase

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1415844328-4884-7-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/callchain.c | 11 ++++++++++-
 tools/perf/util/callchain.h |  1 +
 tools/perf/util/srcline.c   |  6 ++++--
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 38da69c8c1ff..b6624aeaaca9 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -815,7 +815,16 @@ char *callchain_list__sym_name(struct callchain_list *cl,
 	int printed;
 
 	if (cl->ms.sym) {
-		printed = scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
+		if (callchain_param.key == CCKEY_ADDRESS &&
+		    cl->ms.map && !cl->srcline)
+			cl->srcline = get_srcline(cl->ms.map->dso,
+						  map__rip_2objdump(cl->ms.map,
+								    cl->ip));
+		if (cl->srcline)
+			printed = scnprintf(bf, bfsize, "%s %s",
+					cl->ms.sym->name, cl->srcline);
+		else
+			printed = scnprintf(bf, bfsize, "%s", cl->ms.sym->name);
 	} else
 		printed = scnprintf(bf, bfsize, "%#" PRIx64, cl->ip);
 
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index 3e1ed15d11f1..3f158474c892 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -70,6 +70,7 @@ extern struct callchain_param callchain_param;
 struct callchain_list {
 	u64			ip;
 	struct map_symbol	ms;
+	char		       *srcline;
 	struct list_head	list;
 };
 
diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index 77c180637138..ac877f96fed7 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -258,7 +258,7 @@ char *get_srcline(struct dso *dso, unsigned long addr)
 	const char *dso_name;
 
 	if (!dso->has_srcline)
-		return SRCLINE_UNKNOWN;
+		goto out;
 
 	if (dso->symsrc_filename)
 		dso_name = dso->symsrc_filename;
@@ -289,7 +289,9 @@ out:
 		dso->has_srcline = 0;
 		dso__free_a2l(dso);
 	}
-	return SRCLINE_UNKNOWN;
+	if (asprintf(&srcline, "%s[%lx]", dso->short_name, addr) < 0)
+		return SRCLINE_UNKNOWN;
+	return srcline;
 }
 
 void free_srcline(char *srcline)
-- 
1.9.3

[PATCH 04/12] perf symbols: Move bfd_demangle stubbing to its only user

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

We need to define bfd_demangle() to either a wrapper for
cplus_demangle() or to a stub when NO_DEMANGLE is defined.

That is at odds with using bfd.h for some other reason, as it defines
bfd_demangle() and then if code that wants to use symbol.h, where the
above stubbing/wrapping is done, and bfd.h for other reasons, we end up
with a build error where bfd_demangle() is found to be redefined.

Avoid that by moving the stubbing/wrapping to symbol-elf.c, that is the
only user of such function. If we ever get to a point where there are
more valid users, we can then introduce a header for that.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-6wzjpe2fy9xtgchshulixlzw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/symbol-elf.c | 21 +++++++++++++++++++++
 tools/perf/util/symbol.h     | 21 ---------------------
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index efc7eb6b8f0f..06fcd1bf98b6 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -11,6 +11,27 @@
 #include <symbol/kallsyms.h>
 #include "debug.h"
 
+#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
+extern char *cplus_demangle(const char *, int);
+
+static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
+{
+	return cplus_demangle(c, i);
+}
+#else
+#ifdef NO_DEMANGLE
+static inline char *bfd_demangle(void __maybe_unused *v,
+				 const char __maybe_unused *c,
+				 int __maybe_unused i)
+{
+	return NULL;
+}
+#else
+#define PACKAGE 'perf'
+#include <bfd.h>
+#endif
+#endif
+
 #ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
 static int elf_getphdrnum(Elf *elf, size_t *dst)
 {
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index ded3ca7266de..e0b297c50f9d 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -23,27 +23,6 @@
 
 #include "dso.h"
 
-#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
-extern char *cplus_demangle(const char *, int);
-
-static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
-{
-	return cplus_demangle(c, i);
-}
-#else
-#ifdef NO_DEMANGLE
-static inline char *bfd_demangle(void __maybe_unused *v,
-				 const char __maybe_unused *c,
-				 int __maybe_unused i)
-{
-	return NULL;
-}
-#else
-#define PACKAGE 'perf'
-#include <bfd.h>
-#endif
-#endif
-
 /*
  * libelf 0.8.x and earlier do not support ELF_C_READ_MMAP;
  * for newer versions we can use mmap to reduce memory usage:
-- 
1.9.3

[PATCH 05/12] perf callchain: Make get_srcline fall back to sym+offset

[Arnaldo Carvalho de Melo]

From: Andi Kleen <ak@linux.intel.com>

When the source line is not found fall back to sym + offset.  This is
generally much more useful than a raw address.

For this we need to pass in the symbol from the caller.

For some callers it's awkward to compute, so we stay at the old
behaviour.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1415844328-4884-10-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/annotate.c  |  2 +-
 tools/perf/util/callchain.c |  3 ++-
 tools/perf/util/map.c       |  2 +-
 tools/perf/util/sort.c      |  6 ++++--
 tools/perf/util/srcline.c   | 11 +++++++++--
 tools/perf/util/util.h      |  4 +++-
 6 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index e5670f1af737..79999ceaf2be 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1192,7 +1192,7 @@ static int symbol__get_source_line(struct symbol *sym, struct map *map,
 			goto next;
 
 		offset = start + i;
-		src_line->path = get_srcline(map->dso, offset);
+		src_line->path = get_srcline(map->dso, offset, NULL, false);
 		insert_source_line(&tmp_root, src_line);
 
 	next:
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index b6624aeaaca9..517ed84db97a 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -819,7 +819,8 @@ char *callchain_list__sym_name(struct callchain_list *cl,
 		    cl->ms.map && !cl->srcline)
 			cl->srcline = get_srcline(cl->ms.map->dso,
 						  map__rip_2objdump(cl->ms.map,
-								    cl->ip));
+								    cl->ip),
+						  cl->ms.sym, false);
 		if (cl->srcline)
 			printed = scnprintf(bf, bfsize, "%s %s",
 					cl->ms.sym->name, cl->srcline);
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 040a785c857b..62ca9f2607d5 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -360,7 +360,7 @@ int map__fprintf_srcline(struct map *map, u64 addr, const char *prefix,
 
 	if (map && map->dso) {
 		srcline = get_srcline(map->dso,
-				      map__rip_2objdump(map, addr));
+				      map__rip_2objdump(map, addr), NULL, true);
 		if (srcline != SRCLINE_UNKNOWN)
 			ret = fprintf(fp, "%s%s", prefix, srcline);
 		free_srcline(srcline);
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 82a5596241a7..9139dda9f9a3 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -291,7 +291,8 @@ sort__srcline_cmp(struct hist_entry *left, struct hist_entry *right)
 		else {
 			struct map *map = left->ms.map;
 			left->srcline = get_srcline(map->dso,
-					    map__rip_2objdump(map, left->ip));
+					   map__rip_2objdump(map, left->ip),
+						    left->ms.sym, true);
 		}
 	}
 	if (!right->srcline) {
@@ -300,7 +301,8 @@ sort__srcline_cmp(struct hist_entry *left, struct hist_entry *right)
 		else {
 			struct map *map = right->ms.map;
 			right->srcline = get_srcline(map->dso,
-					    map__rip_2objdump(map, right->ip));
+					     map__rip_2objdump(map, right->ip),
+						     right->ms.sym, true);
 		}
 	}
 	return strcmp(right->srcline, left->srcline);
diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index ac877f96fed7..e73b6a5c9e0f 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -8,6 +8,8 @@
 #include "util/util.h"
 #include "util/debug.h"
 
+#include "symbol.h"
+
 #ifdef HAVE_LIBBFD_SUPPORT
 
 /*
@@ -250,7 +252,8 @@ void dso__free_a2l(struct dso *dso __maybe_unused)
  */
 #define A2L_FAIL_LIMIT 123
 
-char *get_srcline(struct dso *dso, unsigned long addr)
+char *get_srcline(struct dso *dso, unsigned long addr, struct symbol *sym,
+		  bool show_sym)
 {
 	char *file = NULL;
 	unsigned line = 0;
@@ -289,7 +292,11 @@ out:
 		dso->has_srcline = 0;
 		dso__free_a2l(dso);
 	}
-	if (asprintf(&srcline, "%s[%lx]", dso->short_name, addr) < 0)
+	if (sym) {
+		if (asprintf(&srcline, "%s+%ld", show_sym ? sym->name : "",
+					addr - sym->start) < 0)
+			return SRCLINE_UNKNOWN;
+	} else if (asprintf(&srcline, "%s[%lx]", dso->short_name, addr) < 0)
 		return SRCLINE_UNKNOWN;
 	return srcline;
 }
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 76d23d83eae5..419bee030f83 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -337,8 +337,10 @@ static inline int path__join3(char *bf, size_t size,
 }
 
 struct dso;
+struct symbol;
 
-char *get_srcline(struct dso *dso, unsigned long addr);
+char *get_srcline(struct dso *dso, unsigned long addr, struct symbol *sym,
+		  bool show_sym);
 void free_srcline(char *srcline);
 
 int filename__read_int(const char *filename, int *value);
-- 
1.9.3

[PATCH 06/12] perf tools: Fix segfault due to invalid kernel dso access

[Arnaldo Carvalho de Melo]

From: Namhyung Kim <namhyung@kernel.org>

Jiri reported that the commit 96d78059d6d9 ("perf tools: Make vmlinux
short name more like kallsyms short name") segfaults on perf script.

When processing kernel mmap event, it should access the 'kernel'
variable as sometimes it cannot find a matching dso from build-id table
so 'dso' might be invalid.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1416285028-30572-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/machine.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index d97309c87bd6..b75b487574c7 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1106,8 +1106,8 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
 		if (__machine__create_kernel_maps(machine, kernel) < 0)
 			goto out_problem;
 
-		if (strstr(dso->long_name, "vmlinux"))
-			dso__set_short_name(dso, "[kernel.vmlinux]", false);
+		if (strstr(kernel->long_name, "vmlinux"))
+			dso__set_short_name(kernel, "[kernel.vmlinux]", false);
 
 		machine__set_kernel_mmap_len(machine, event);
 
-- 
1.9.3

[PATCH 07/12] perf tools: Allow to force redirect pr_debug to stderr.

[Arnaldo Carvalho de Melo]

From: Andi Kleen <ak@linux.intel.com>

When debugging the tui browser I find it useful to redirect the debug
log into a file. Currently it's always forced to the message line.

Add an option to force it to stderr. Then it can be easily redirected.

Example:

  [root@zoo ~]# perf --debug stderr report -vv 2> /tmp/debug
  [root@zoo ~]# tail /tmp/debug
  dso open failed, mmap: No such file or directory
  dso open failed, mmap: No such file or directory
  dso open failed, mmap: No such file or directory
  dso open failed, mmap: No such file or directory
  dso open failed, mmap: No such file or directory
  Using /root/.debug/.build-id/4e/841948927029fb650132253642d5dbb2c1fb93 for symbols
  Failed to open /tmp/perf-8831.map, continuing without symbols
  Failed to open /tmp/perf-12721.map, continuing without symbols
  Failed to open /tmp/perf-6966.map, continuing without symbols
  Failed to open /tmp/perf-8802.map, continuing without symbols
  [root@zoo ~]#

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1416605880-25055-2-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/debug.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index ba357f3226c6..ad60b2f20258 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -19,13 +19,14 @@
 int verbose;
 bool dump_trace = false, quiet = false;
 int debug_ordered_events;
+static int redirect_to_stderr;
 
 static int _eprintf(int level, int var, const char *fmt, va_list args)
 {
 	int ret = 0;
 
 	if (var >= level) {
-		if (use_browser >= 1)
+		if (use_browser >= 1 && !redirect_to_stderr)
 			ui_helpline__vshow(fmt, args);
 		else
 			ret = vfprintf(stderr, fmt, args);
@@ -145,6 +146,7 @@ static struct debug_variable {
 } debug_variables[] = {
 	{ .name = "verbose",		.ptr = &verbose },
 	{ .name = "ordered-events",	.ptr = &debug_ordered_events},
+	{ .name = "stderr",		.ptr = &redirect_to_stderr},
 	{ .name = NULL, }
 };
 
-- 
1.9.3

[PATCH 08/12] perf evsel: Introduce perf_evsel__compute_deltas function

[Arnaldo Carvalho de Melo]

From: Jiri Olsa <jolsa@kernel.org>

Making compute_deltas functions global and renaming it to
perf_evsel__compute_deltas.

It will be used in stat command in later patch.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1416562275-12404-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evsel.c | 9 ++++-----
 tools/perf/util/evsel.h | 3 +++
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index f2dc91fb87fa..1c73bc4d57d3 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -876,9 +876,8 @@ void perf_evsel__delete(struct perf_evsel *evsel)
 	free(evsel);
 }
 
-static inline void compute_deltas(struct perf_evsel *evsel,
-				  int cpu,
-				  struct perf_counts_values *count)
+void perf_evsel__compute_deltas(struct perf_evsel *evsel, int cpu,
+				struct perf_counts_values *count)
 {
 	struct perf_counts_values tmp;
 
@@ -913,7 +912,7 @@ int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 	if (readn(FD(evsel, cpu, thread), &count, nv * sizeof(u64)) < 0)
 		return -errno;
 
-	compute_deltas(evsel, cpu, &count);
+	perf_evsel__compute_deltas(evsel, cpu, &count);
 
 	if (scale) {
 		if (count.run == 0)
@@ -956,7 +955,7 @@ int __perf_evsel__read(struct perf_evsel *evsel,
 		}
 	}
 
-	compute_deltas(evsel, -1, aggr);
+	perf_evsel__compute_deltas(evsel, -1, aggr);
 
 	evsel->counts->scaled = 0;
 	if (scale) {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 979790951bfb..746b7ea84589 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -110,6 +110,9 @@ struct thread_map;
 struct perf_evlist;
 struct record_opts;
 
+void perf_evsel__compute_deltas(struct perf_evsel *evsel, int cpu,
+				struct perf_counts_values *count);
+
 int perf_evsel__object_config(size_t object_size,
 			      int (*init)(struct perf_evsel *evsel),
 			      void (*fini)(struct perf_evsel *evsel));
-- 
1.9.3

[PATCH 09/12] perf evsel: Introduce perf_counts_values__scale function

[Arnaldo Carvalho de Melo]

From: Jiri Olsa <jolsa@kernel.org>

Factoring out scale login into perf_counts_values__scale function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1416562275-12404-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evsel.c | 47 ++++++++++++++++++++++-------------------------
 tools/perf/util/evsel.h |  3 +++
 2 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1c73bc4d57d3..6dc7a67e6d35 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -897,6 +897,26 @@ void perf_evsel__compute_deltas(struct perf_evsel *evsel, int cpu,
 	count->run = count->run - tmp.run;
 }
 
+void perf_counts_values__scale(struct perf_counts_values *count,
+			       bool scale, s8 *pscaled)
+{
+	s8 scaled = 0;
+
+	if (scale) {
+		if (count->run == 0) {
+			scaled = -1;
+			count->val = 0;
+		} else if (count->run < count->ena) {
+			scaled = 1;
+			count->val = (u64)((double) count->val * count->ena / count->run + 0.5);
+		}
+	} else
+		count->ena = count->run = 0;
+
+	if (pscaled)
+		*pscaled = scaled;
+}
+
 int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 			      int cpu, int thread, bool scale)
 {
@@ -913,15 +933,7 @@ int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 		return -errno;
 
 	perf_evsel__compute_deltas(evsel, cpu, &count);
-
-	if (scale) {
-		if (count.run == 0)
-			count.val = 0;
-		else if (count.run < count.ena)
-			count.val = (u64)((double)count.val * count.ena / count.run + 0.5);
-	} else
-		count.ena = count.run = 0;
-
+	perf_counts_values__scale(&count, scale, NULL);
 	evsel->counts->cpu[cpu] = count;
 	return 0;
 }
@@ -956,22 +968,7 @@ int __perf_evsel__read(struct perf_evsel *evsel,
 	}
 
 	perf_evsel__compute_deltas(evsel, -1, aggr);
-
-	evsel->counts->scaled = 0;
-	if (scale) {
-		if (aggr->run == 0) {
-			evsel->counts->scaled = -1;
-			aggr->val = 0;
-			return 0;
-		}
-
-		if (aggr->run < aggr->ena) {
-			evsel->counts->scaled = 1;
-			aggr->val = (u64)((double)aggr->val * aggr->ena / aggr->run + 0.5);
-		}
-	} else
-		aggr->ena = aggr->run = 0;
-
+	perf_counts_values__scale(aggr, scale, &evsel->counts->scaled);
 	return 0;
 }
 
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 746b7ea84589..7af0377ceb18 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -110,6 +110,9 @@ struct thread_map;
 struct perf_evlist;
 struct record_opts;
 
+void perf_counts_values__scale(struct perf_counts_values *count,
+			       bool scale, s8 *pscaled);
+
 void perf_evsel__compute_deltas(struct perf_evsel *evsel, int cpu,
 				struct perf_counts_values *count);
 
-- 
1.9.3

[PATCH 10/12] perf evsel: Introduce perf_evsel__read_cb function

[Arnaldo Carvalho de Melo]

From: Jiri Olsa <jolsa@kernel.org>

Adding perf_evsel__read_cb read function that retuns count values via
callback. It will be used later in stat command as single way to
retrieve counter values.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1416562275-12404-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evsel.c | 16 ++++++++++++++++
 tools/perf/util/evsel.h |  7 +++++++
 2 files changed, 23 insertions(+)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 6dc7a67e6d35..2d26b7ad6fe0 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -917,6 +917,22 @@ void perf_counts_values__scale(struct perf_counts_values *count,
 		*pscaled = scaled;
 }
 
+int perf_evsel__read_cb(struct perf_evsel *evsel, int cpu, int thread,
+			perf_evsel__read_cb_t cb)
+{
+	struct perf_counts_values count;
+
+	memset(&count, 0, sizeof(count));
+
+	if (FD(evsel, cpu, thread) < 0)
+		return -EINVAL;
+
+	if (readn(FD(evsel, cpu, thread), &count, sizeof(count)) < 0)
+		return -errno;
+
+	return cb(evsel, cpu, thread, &count);
+}
+
 int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 			      int cpu, int thread, bool scale)
 {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 7af0377ceb18..5c93bed8e8d9 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -233,6 +233,13 @@ static inline bool perf_evsel__match2(struct perf_evsel *e1,
 	 (a)->attr.type == (b)->attr.type &&	\
 	 (a)->attr.config == (b)->attr.config)
 
+typedef int (perf_evsel__read_cb_t)(struct perf_evsel *evsel,
+				    int cpu, int thread,
+				    struct perf_counts_values *count);
+
+int perf_evsel__read_cb(struct perf_evsel *evsel, int cpu, int thread,
+			perf_evsel__read_cb_t cb);
+
 int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 			      int cpu, int thread, bool scale);
 
-- 
1.9.3

[PATCH 11/12] perf tools: Add per-pkg format file parsing

[Arnaldo Carvalho de Melo]

From: Matt Fleming <matt.fleming@intel.com>

The .per-pkg file indicates that all but one value per socket should be
discarded. Adding support to check up this file and set event flag
accordingly.

This patch is part of Matt's original patch:

http://marc.info/?l=linux-kernel&m=141527675002139&w=2 only the file
parsing part, the rest is solved differently.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1416562275-12404-9-git-send-email-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evsel.h        |  1 +
 tools/perf/util/parse-events.c |  1 +
 tools/perf/util/pmu.c          | 27 +++++++++++++++++++++++++++
 tools/perf/util/pmu.h          |  2 ++
 4 files changed, 31 insertions(+)

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 5c93bed8e8d9..792b0ea8a8b8 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -91,6 +91,7 @@ struct perf_evsel {
 	bool			immediate;
 	bool			system_wide;
 	bool			tracking;
+	bool			per_pkg;
 	/* parse modifier helper */
 	int			exclude_GH;
 	int			nr_members;
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index c659a3ca1283..5a373483f0e4 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -681,6 +681,7 @@ int parse_events_add_pmu(struct list_head *list, int *idx,
 	if (evsel) {
 		evsel->unit = info.unit;
 		evsel->scale = info.scale;
+		evsel->per_pkg = info.per_pkg;
 	}
 
 	return evsel ? 0 : -ENOMEM;
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 881b75490533..f003b5a9e059 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -163,6 +163,24 @@ error:
 	return -1;
 }
 
+static int
+perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, char *dir, char *name)
+{
+	char path[PATH_MAX];
+	int fd;
+
+	snprintf(path, PATH_MAX, "%s/%s.per-pkg", dir, name);
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		return -1;
+
+	close(fd);
+
+	alias->per_pkg = true;
+	return 0;
+}
+
 static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FILE *file)
 {
 	struct perf_pmu_alias *alias;
@@ -181,6 +199,7 @@ static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FI
 	INIT_LIST_HEAD(&alias->terms);
 	alias->scale = 1.0;
 	alias->unit[0] = '\0';
+	alias->per_pkg = false;
 
 	ret = parse_events_terms(&alias->terms, buf);
 	if (ret) {
@@ -194,6 +213,7 @@ static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FI
 	 */
 	perf_pmu__parse_unit(alias, dir, name);
 	perf_pmu__parse_scale(alias, dir, name);
+	perf_pmu__parse_per_pkg(alias, dir, name);
 
 	list_add_tail(&alias->list, list);
 
@@ -209,6 +229,8 @@ static inline bool pmu_alias_info_file(char *name)
 		return true;
 	if (len > 6 && !strcmp(name + len - 6, ".scale"))
 		return true;
+	if (len > 8 && !strcmp(name + len - 8, ".per-pkg"))
+		return true;
 
 	return false;
 }
@@ -649,6 +671,8 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
 	struct perf_pmu_alias *alias;
 	int ret;
 
+	info->per_pkg = false;
+
 	/*
 	 * Mark unit and scale as not set
 	 * (different from default values, see below)
@@ -668,6 +692,9 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
 		if (ret)
 			return ret;
 
+		if (alias->per_pkg)
+			info->per_pkg = true;
+
 		list_del(&term->list);
 		free(term);
 	}
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 8092de78e818..c3a74e0e17a2 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -29,6 +29,7 @@ struct perf_pmu {
 struct perf_pmu_info {
 	const char *unit;
 	double scale;
+	bool per_pkg;
 };
 
 #define UNIT_MAX_LEN	31 /* max length for event unit name */
@@ -39,6 +40,7 @@ struct perf_pmu_alias {
 	struct list_head list;  /* ELEM */
 	char unit[UNIT_MAX_LEN+1];
 	double scale;
+	bool per_pkg;
 };
 
 struct perf_pmu *perf_pmu__find(const char *name);
-- 
1.9.3

[PATCH 12/12] perf tools: Add snapshot format file parsing

[Arnaldo Carvalho de Melo]

From: Jiri Olsa <jolsa@kernel.org>

The .snapshot file indicates that the provided event value is a snapshot
value and we have to bypass the delta computation logic.

Adding support to check up this file and set event flag accordingly.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1416562275-12404-10-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evsel.h        |  1 +
 tools/perf/util/parse-events.c |  1 +
 tools/perf/util/pmu.c          | 47 ++++++++++++++++++++++++++++++++----------
 tools/perf/util/pmu.h          |  2 ++
 4 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 792b0ea8a8b8..b18d58da580b 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -73,6 +73,7 @@ struct perf_evsel {
 	char			*name;
 	double			scale;
 	const char		*unit;
+	bool			snapshot;
 	struct event_format	*tp_format;
 	union {
 		void		*priv;
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 5a373483f0e4..77b43fe43d55 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -682,6 +682,7 @@ int parse_events_add_pmu(struct list_head *list, int *idx,
 		evsel->unit = info.unit;
 		evsel->scale = info.scale;
 		evsel->per_pkg = info.per_pkg;
+		evsel->snapshot = info.snapshot;
 	}
 
 	return evsel ? 0 : -ENOMEM;
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index f003b5a9e059..5c9c4947cfb4 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -181,6 +181,23 @@ perf_pmu__parse_per_pkg(struct perf_pmu_alias *alias, char *dir, char *name)
 	return 0;
 }
 
+static int perf_pmu__parse_snapshot(struct perf_pmu_alias *alias,
+				    char *dir, char *name)
+{
+	char path[PATH_MAX];
+	int fd;
+
+	snprintf(path, PATH_MAX, "%s/%s.snapshot", dir, name);
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		return -1;
+
+	alias->snapshot = true;
+	close(fd);
+	return 0;
+}
+
 static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FILE *file)
 {
 	struct perf_pmu_alias *alias;
@@ -214,6 +231,7 @@ static int perf_pmu__new_alias(struct list_head *list, char *dir, char *name, FI
 	perf_pmu__parse_unit(alias, dir, name);
 	perf_pmu__parse_scale(alias, dir, name);
 	perf_pmu__parse_per_pkg(alias, dir, name);
+	perf_pmu__parse_snapshot(alias, dir, name);
 
 	list_add_tail(&alias->list, list);
 
@@ -231,6 +249,8 @@ static inline bool pmu_alias_info_file(char *name)
 		return true;
 	if (len > 8 && !strcmp(name + len - 8, ".per-pkg"))
 		return true;
+	if (len > 9 && !strcmp(name + len - 9, ".snapshot"))
+		return true;
 
 	return false;
 }
@@ -639,23 +659,27 @@ static struct perf_pmu_alias *pmu_find_alias(struct perf_pmu *pmu,
 }
 
 
-static int check_unit_scale(struct perf_pmu_alias *alias,
-			    const char **unit, double *scale)
+static int check_info_data(struct perf_pmu_alias *alias,
+			   struct perf_pmu_info *info)
 {
 	/*
 	 * Only one term in event definition can
-	 * define unit and scale, fail if there's
-	 * more than one.
+	 * define unit, scale and snapshot, fail
+	 * if there's more than one.
 	 */
-	if ((*unit && alias->unit) ||
-	    (*scale && alias->scale))
+	if ((info->unit && alias->unit) ||
+	    (info->scale && alias->scale) ||
+	    (info->snapshot && alias->snapshot))
 		return -EINVAL;
 
 	if (alias->unit)
-		*unit = alias->unit;
+		info->unit = alias->unit;
 
 	if (alias->scale)
-		*scale = alias->scale;
+		info->scale = alias->scale;
+
+	if (alias->snapshot)
+		info->snapshot = alias->snapshot;
 
 	return 0;
 }
@@ -677,8 +701,9 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
 	 * Mark unit and scale as not set
 	 * (different from default values, see below)
 	 */
-	info->unit   = NULL;
-	info->scale  = 0.0;
+	info->unit     = NULL;
+	info->scale    = 0.0;
+	info->snapshot = false;
 
 	list_for_each_entry_safe(term, h, head_terms, list) {
 		alias = pmu_find_alias(pmu, term);
@@ -688,7 +713,7 @@ int perf_pmu__check_alias(struct perf_pmu *pmu, struct list_head *head_terms,
 		if (ret)
 			return ret;
 
-		ret = check_unit_scale(alias, &info->unit, &info->scale);
+		ret = check_info_data(alias, info);
 		if (ret)
 			return ret;
 
diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index c3a74e0e17a2..6b1249fbdb5f 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -30,6 +30,7 @@ struct perf_pmu_info {
 	const char *unit;
 	double scale;
 	bool per_pkg;
+	bool snapshot;
 };
 
 #define UNIT_MAX_LEN	31 /* max length for event unit name */
@@ -41,6 +42,7 @@ struct perf_pmu_alias {
 	char unit[UNIT_MAX_LEN+1];
 	double scale;
 	bool per_pkg;
+	bool snapshot;
 };
 
 struct perf_pmu *perf_pmu__find(const char *name);
-- 
1.9.3