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authorLinus Torvalds <torvalds@linux-foundation.org>2012-03-20 10:29:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-20 10:29:15 -0700
commit9c2b957db1772ebf942ae7a9346b14eba6c8ca66 (patch)
tree0dbb83e57260ea7fc0dc421f214d5f1b26262005 /tools/perf/util/session.c
parent0bbfcaff9b2a69c71a95e6902253487ab30cb498 (diff)
parentbea95c152dee1791dd02cbc708afbb115bb00f9a (diff)
downloadlinux-9c2b957db1772ebf942ae7a9346b14eba6c8ca66.tar.gz
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events changes for v3.4 from Ingo Molnar:

 - New "hardware based branch profiling" feature both on the kernel and
   the tooling side, on CPUs that support it.  (modern x86 Intel CPUs
   with the 'LBR' hardware feature currently.)

   This new feature is basically a sophisticated 'magnifying glass' for
   branch execution - something that is pretty difficult to extract from
   regular, function histogram centric profiles.

   The simplest mode is activated via 'perf record -b', and the result
   looks like this in perf report:

	$ perf record -b any_call,u -e cycles:u branchy

	$ perf report -b --sort=symbol
	    52.34%  [.] main                   [.] f1
	    24.04%  [.] f1                     [.] f3
	    23.60%  [.] f1                     [.] f2
	     0.01%  [k] _IO_new_file_xsputn    [k] _IO_file_overflow
	     0.01%  [k] _IO_vfprintf_internal  [k] _IO_new_file_xsputn
	     0.01%  [k] _IO_vfprintf_internal  [k] strchrnul
	     0.01%  [k] __printf               [k] _IO_vfprintf_internal
	     0.01%  [k] main                   [k] __printf

   This output shows from/to branch columns and shows the highest
   percentage (from,to) jump combinations - i.e.  the most likely taken
   branches in the system.  "branches" can also include function calls
   and any other synchronous and asynchronous transitions of the
   instruction pointer that are not 'next instruction' - such as system
   calls, traps, interrupts, etc.

   This feature comes with (hopefully intuitive) flat ascii and TUI
   support in perf report.

 - Various 'perf annotate' visual improvements for us assembly junkies.
   It will now recognize function calls in the TUI and by hitting enter
   you can follow the call (recursively) and back, amongst other
   improvements.

 - Multiple threads/processes recording support in perf record, perf
   stat, perf top - which is activated via a comma-list of PIDs:

	perf top -p 21483,21485
	perf stat -p 21483,21485 -ddd
	perf record -p 21483,21485

 - Support for per UID views, via the --uid paramter to perf top, perf
   report, etc.  For example 'perf top --uid mingo' will only show the
   tasks that I am running, excluding other users, root, etc.

 - Jump label restructurings and improvements - this includes the
   factoring out of the (hopefully much clearer) include/linux/static_key.h
   generic facility:

	struct static_key key = STATIC_KEY_INIT_FALSE;

	...

	if (static_key_false(&key))
	        do unlikely code
	else
	        do likely code

	...
	static_key_slow_inc();
	...
	static_key_slow_inc();
	...

   The static_key_false() branch will be generated into the code with as
   little impact to the likely code path as possible.  the
   static_key_slow_*() APIs flip the branch via live kernel code patching.

   This facility can now be used more widely within the kernel to
   micro-optimize hot branches whose likelihood matches the static-key
   usage and fast/slow cost patterns.

 - SW function tracer improvements: perf support and filtering support.

 - Various hardenings of the perf.data ABI, to make older perf.data's
   smoother on newer tool versions, to make new features integrate more
   smoothly, to support cross-endian recording/analyzing workflows
   better, etc.

 - Restructuring of the kprobes code, the splitting out of 'optprobes',
   and a corner case bugfix.

 - Allow the tracing of kernel console output (printk).

 - Improvements/fixes to user-space RDPMC support, allowing user-space
   self-profiling code to extract PMU counts without performing any
   system calls, while playing nice with the kernel side.

 - 'perf bench' improvements

 - ... and lots of internal restructurings, cleanups and fixes that made
   these features possible.  And, as usual this list is incomplete as
   there were also lots of other improvements

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (120 commits)
  perf report: Fix annotate double quit issue in branch view mode
  perf report: Remove duplicate annotate choice in branch view mode
  perf/x86: Prettify pmu config literals
  perf report: Enable TUI in branch view mode
  perf report: Auto-detect branch stack sampling mode
  perf record: Add HEADER_BRANCH_STACK tag
  perf record: Provide default branch stack sampling mode option
  perf tools: Make perf able to read files from older ABIs
  perf tools: Fix ABI compatibility bug in print_event_desc()
  perf tools: Enable reading of perf.data files from different ABI rev
  perf: Add ABI reference sizes
  perf report: Add support for taken branch sampling
  perf record: Add support for sampling taken branch
  perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK
  x86/kprobes: Split out optprobe related code to kprobes-opt.c
  x86/kprobes: Fix a bug which can modify kernel code permanently
  x86/kprobes: Fix instruction recovery on optimized path
  perf: Add callback to flush branch_stack on context switch
  perf: Disable PERF_SAMPLE_BRANCH_* when not supported
  perf/x86: Add LBR software filter support for Intel CPUs
  ...
Diffstat (limited to 'tools/perf/util/session.c')
-rw-r--r--tools/perf/util/session.c126
1 files changed, 99 insertions, 27 deletions
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b5ca2558c7bb..002ebbf59f48 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -24,7 +24,7 @@ static int perf_session__open(struct perf_session *self, bool force)
 		self->fd = STDIN_FILENO;
 
 		if (perf_session__read_header(self, self->fd) < 0)
-			pr_err("incompatible file format");
+			pr_err("incompatible file format (rerun with -v to learn more)");
 
 		return 0;
 	}
@@ -56,7 +56,7 @@ static int perf_session__open(struct perf_session *self, bool force)
 	}
 
 	if (perf_session__read_header(self, self->fd) < 0) {
-		pr_err("incompatible file format");
+		pr_err("incompatible file format (rerun with -v to learn more)");
 		goto out_close;
 	}
 
@@ -229,6 +229,64 @@ static bool symbol__match_parent_regex(struct symbol *sym)
 	return 0;
 }
 
+static const u8 cpumodes[] = {
+	PERF_RECORD_MISC_USER,
+	PERF_RECORD_MISC_KERNEL,
+	PERF_RECORD_MISC_GUEST_USER,
+	PERF_RECORD_MISC_GUEST_KERNEL
+};
+#define NCPUMODES (sizeof(cpumodes)/sizeof(u8))
+
+static void ip__resolve_ams(struct machine *self, struct thread *thread,
+			    struct addr_map_symbol *ams,
+			    u64 ip)
+{
+	struct addr_location al;
+	size_t i;
+	u8 m;
+
+	memset(&al, 0, sizeof(al));
+
+	for (i = 0; i < NCPUMODES; i++) {
+		m = cpumodes[i];
+		/*
+		 * We cannot use the header.misc hint to determine whether a
+		 * branch stack address is user, kernel, guest, hypervisor.
+		 * Branches may straddle the kernel/user/hypervisor boundaries.
+		 * Thus, we have to try consecutively until we find a match
+		 * or else, the symbol is unknown
+		 */
+		thread__find_addr_location(thread, self, m, MAP__FUNCTION,
+				ip, &al, NULL);
+		if (al.sym)
+			goto found;
+	}
+found:
+	ams->addr = ip;
+	ams->al_addr = al.addr;
+	ams->sym = al.sym;
+	ams->map = al.map;
+}
+
+struct branch_info *machine__resolve_bstack(struct machine *self,
+					    struct thread *thr,
+					    struct branch_stack *bs)
+{
+	struct branch_info *bi;
+	unsigned int i;
+
+	bi = calloc(bs->nr, sizeof(struct branch_info));
+	if (!bi)
+		return NULL;
+
+	for (i = 0; i < bs->nr; i++) {
+		ip__resolve_ams(self, thr, &bi[i].to, bs->entries[i].to);
+		ip__resolve_ams(self, thr, &bi[i].from, bs->entries[i].from);
+		bi[i].flags = bs->entries[i].flags;
+	}
+	return bi;
+}
+
 int machine__resolve_callchain(struct machine *self, struct perf_evsel *evsel,
 			       struct thread *thread,
 			       struct ip_callchain *chain,
@@ -697,6 +755,18 @@ static void callchain__printf(struct perf_sample *sample)
 		       i, sample->callchain->ips[i]);
 }
 
+static void branch_stack__printf(struct perf_sample *sample)
+{
+	uint64_t i;
+
+	printf("... branch stack: nr:%" PRIu64 "\n", sample->branch_stack->nr);
+
+	for (i = 0; i < sample->branch_stack->nr; i++)
+		printf("..... %2"PRIu64": %016" PRIx64 " -> %016" PRIx64 "\n",
+			i, sample->branch_stack->entries[i].from,
+			sample->branch_stack->entries[i].to);
+}
+
 static void perf_session__print_tstamp(struct perf_session *session,
 				       union perf_event *event,
 				       struct perf_sample *sample)
@@ -744,6 +814,9 @@ static void dump_sample(struct perf_session *session, union perf_event *event,
 
 	if (session->sample_type & PERF_SAMPLE_CALLCHAIN)
 		callchain__printf(sample);
+
+	if (session->sample_type & PERF_SAMPLE_BRANCH_STACK)
+		branch_stack__printf(sample);
 }
 
 static struct machine *
@@ -796,6 +869,10 @@ static int perf_session_deliver_event(struct perf_session *session,
 			++session->hists.stats.nr_unknown_id;
 			return -1;
 		}
+		if (machine == NULL) {
+			++session->hists.stats.nr_unprocessable_samples;
+			return -1;
+		}
 		return tool->sample(tool, event, sample, evsel, machine);
 	case PERF_RECORD_MMAP:
 		return tool->mmap(tool, event, sample, machine);
@@ -964,6 +1041,12 @@ static void perf_session__warn_about_errors(const struct perf_session *session,
  			    session->hists.stats.nr_invalid_chains,
  			    session->hists.stats.nr_events[PERF_RECORD_SAMPLE]);
  	}
+
+	if (session->hists.stats.nr_unprocessable_samples != 0) {
+		ui__warning("%u unprocessable samples recorded.\n"
+			    "Do you have a KVM guest running and not using 'perf kvm'?\n",
+			    session->hists.stats.nr_unprocessable_samples);
+	}
 }
 
 #define session_done()	(*(volatile int *)(&session_done))
@@ -1293,10 +1376,9 @@ struct perf_evsel *perf_session__find_first_evtype(struct perf_session *session,
 
 void perf_event__print_ip(union perf_event *event, struct perf_sample *sample,
 			  struct machine *machine, struct perf_evsel *evsel,
-			  int print_sym, int print_dso)
+			  int print_sym, int print_dso, int print_symoffset)
 {
 	struct addr_location al;
-	const char *symname, *dsoname;
 	struct callchain_cursor *cursor = &evsel->hists.callchain_cursor;
 	struct callchain_cursor_node *node;
 
@@ -1324,20 +1406,13 @@ void perf_event__print_ip(union perf_event *event, struct perf_sample *sample,
 
 			printf("\t%16" PRIx64, node->ip);
 			if (print_sym) {
-				if (node->sym && node->sym->name)
-					symname = node->sym->name;
-				else
-					symname = "";
-
-				printf(" %s", symname);
+				printf(" ");
+				symbol__fprintf_symname(node->sym, stdout);
 			}
 			if (print_dso) {
-				if (node->map && node->map->dso && node->map->dso->name)
-					dsoname = node->map->dso->name;
-				else
-					dsoname = "";
-
-				printf(" (%s)", dsoname);
+				printf(" (");
+				map__fprintf_dsoname(al.map, stdout);
+				printf(")");
 			}
 			printf("\n");
 
@@ -1347,21 +1422,18 @@ void perf_event__print_ip(union perf_event *event, struct perf_sample *sample,
 	} else {
 		printf("%16" PRIx64, sample->ip);
 		if (print_sym) {
-			if (al.sym && al.sym->name)
-				symname = al.sym->name;
+			printf(" ");
+			if (print_symoffset)
+				symbol__fprintf_symname_offs(al.sym, &al,
+							     stdout);
 			else
-				symname = "";
-
-			printf(" %s", symname);
+				symbol__fprintf_symname(al.sym, stdout);
 		}
 
 		if (print_dso) {
-			if (al.map && al.map->dso && al.map->dso->name)
-				dsoname = al.map->dso->name;
-			else
-				dsoname = "";
-
-			printf(" (%s)", dsoname);
+			printf(" (");
+			map__fprintf_dsoname(al.map, stdout);
+			printf(")");
 		}
 	}
 }