Merge tag 'perf-core-for-mingo' of...

Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

 * Don't install scripting files files when perl/python support is disabled.

 * Support ! in -e expressions in 'perf trace', to filter a list of syscalls.

 * Add --verbose and -o/--output options to 'perf trace'.

 * Introduce better formatting of syscall arguments in 'perf trace',
   including so far beautifiers for mmap, madvise, syscall return
   values.

 * Fixup jobserver setup in libtraceevent makefile.

 * Debug improvements from Adrian Hunter.

 * Try to increase the file descriptor limits on EMFILE, from Andi Kleen.

 * Remove unused force option in 'perf kvm', from David Ahern.

 * Make 'perf trace' command line arguments consistent with 'perf record',
   from David Ahern.

 * Fix correlation of samples coming after PERF_RECORD_EXIT event, from
   David Ahern.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/lib/traceevent/Makefile

@@ -60,7 +60,7 @@ ifeq ($(BUILD_SRC),)
 ifneq ($(BUILD_OUTPUT),)
 
 define build_output
-	$(if $(VERBOSE:1=),@)$(MAKE) -C $(BUILD_OUTPUT) 	\
+	$(if $(VERBOSE:1=),@)+$(MAKE) -C $(BUILD_OUTPUT) 	\
 	BUILD_SRC=$(CURDIR) -f $(CURDIR)/Makefile $1
 endef
 

tools/perf/Documentation/perf-trace.txt

@@ -23,29 +23,45 @@ analysis phases.
 OPTIONS
 -------
 
+-a::
 --all-cpus::
         System-wide collection from all CPUs.
 
 -e::
 --expr::
 	List of events to show, currently only syscall names.
+	Prefixing with ! shows all syscalls but the ones specified.  You may
+	need to escape it.
+
+-o::
+--output=::
+	Output file name.
 
 -p::
 --pid=::
 	Record events on existing process ID (comma separated list).
 
+-t::
 --tid=::
         Record events on existing thread ID (comma separated list).
 
+-u::
 --uid=::
         Record events in threads owned by uid. Name or number.
 
+-v::
+--verbose=::
+        Verbosity level.
+
+-i::
 --no-inherit::
 	Child tasks do not inherit counters.
 
+-m::
 --mmap-pages=::
 	Number of mmap data pages. Must be a power of two.
 
+-C::
 --cpu::
 Collect samples only on the list of CPUs provided. Multiple CPUs can be provided as a
 comma-separated list with no space: 0,1. Ranges of CPUs are specified with -: 0-2.

tools/perf/Makefile

@@ -766,17 +766,21 @@ check: $(OUTPUT)common-cmds.h
 install-bin: all
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(bindir_SQ)'
 	$(INSTALL) $(OUTPUT)perf '$(DESTDIR_SQ)$(bindir_SQ)'
+	$(INSTALL) $(OUTPUT)perf-archive -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'
+ifndef NO_LIBPERL
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/Perf-Trace-Util/lib/Perf/Trace'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/bin'
-	$(INSTALL) $(OUTPUT)perf-archive -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'
 	$(INSTALL) scripts/perl/Perf-Trace-Util/lib/Perf/Trace/* -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/Perf-Trace-Util/lib/Perf/Trace'
 	$(INSTALL) scripts/perl/*.pl -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl'
 	$(INSTALL) scripts/perl/bin/* -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/bin'
+endif
+ifndef NO_LIBPYTHON
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/python/Perf-Trace-Util/lib/Perf/Trace'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/python/bin'
 	$(INSTALL) scripts/python/Perf-Trace-Util/lib/Perf/Trace/* -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/python/Perf-Trace-Util/lib/Perf/Trace'
 	$(INSTALL) scripts/python/*.py -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/python'
 	$(INSTALL) scripts/python/bin/* -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/python/bin'
+endif
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(sysconfdir_SQ)/bash_completion.d'
 	$(INSTALL) bash_completion '$(DESTDIR_SQ)$(sysconfdir_SQ)/bash_completion.d/perf'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/tests'

tools/perf/builtin-kvm.c

@@ -1305,7 +1305,6 @@ kvm_events_record(struct perf_kvm_stat *kvm, int argc, const char **argv)
 	const char * const record_args[] = {
 		"record",
 		"-R",
-		"-f",
 		"-m", "1024",
 		"-c", "1",
 	};

tools/perf/builtin-trace.c

 #include <traceevent/event-parse.h>
 #include "builtin.h"
 #include "util/color.h"
+#include "util/debug.h"
 #include "util/evlist.h"
 #include "util/machine.h"
 #include "util/thread.h"
@@ -10,27 +11,166 @@
 
 #include <libaudit.h>
 #include <stdlib.h>
+#include <sys/mman.h>
+
+static size_t syscall_arg__scnprintf_hex(char *bf, size_t size, unsigned long arg)
+{
+	return scnprintf(bf, size, "%#lx", arg);
+}
+
+#define SCA_HEX syscall_arg__scnprintf_hex
+
+static size_t syscall_arg__scnprintf_mmap_prot(char *bf, size_t size, unsigned long arg)
+{
+	int printed = 0, prot = arg;
+
+	if (prot == PROT_NONE)
+		return scnprintf(bf, size, "NONE");
+#define	P_MMAP_PROT(n) \
+	if (prot & PROT_##n) { \
+		printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "|" : "", #n); \
+		prot &= ~PROT_##n; \
+	}
+
+	P_MMAP_PROT(EXEC);
+	P_MMAP_PROT(READ);
+	P_MMAP_PROT(WRITE);
+#ifdef PROT_SEM
+	P_MMAP_PROT(SEM);
+#endif
+	P_MMAP_PROT(GROWSDOWN);
+	P_MMAP_PROT(GROWSUP);
+#undef P_MMAP_PROT
+
+	if (prot)
+		printed += scnprintf(bf + printed, size - printed, "%s%#x", printed ? "|" : "", prot);
+
+	return printed;
+}
+
+#define SCA_MMAP_PROT syscall_arg__scnprintf_mmap_prot
+
+static size_t syscall_arg__scnprintf_mmap_flags(char *bf, size_t size, unsigned long arg)
+{
+	int printed = 0, flags = arg;
+
+#define	P_MMAP_FLAG(n) \
+	if (flags & MAP_##n) { \
+		printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "|" : "", #n); \
+		flags &= ~MAP_##n; \
+	}
+
+	P_MMAP_FLAG(SHARED);
+	P_MMAP_FLAG(PRIVATE);
+	P_MMAP_FLAG(32BIT);
+	P_MMAP_FLAG(ANONYMOUS);
+	P_MMAP_FLAG(DENYWRITE);
+	P_MMAP_FLAG(EXECUTABLE);
+	P_MMAP_FLAG(FILE);
+	P_MMAP_FLAG(FIXED);
+	P_MMAP_FLAG(GROWSDOWN);
+	P_MMAP_FLAG(HUGETLB);
+	P_MMAP_FLAG(LOCKED);
+	P_MMAP_FLAG(NONBLOCK);
+	P_MMAP_FLAG(NORESERVE);
+	P_MMAP_FLAG(POPULATE);
+	P_MMAP_FLAG(STACK);
+#ifdef MAP_UNINITIALIZED
+	P_MMAP_FLAG(UNINITIALIZED);
+#endif
+#undef P_MMAP_FLAG
+
+	if (flags)
+		printed += scnprintf(bf + printed, size - printed, "%s%#x", printed ? "|" : "", flags);
+
+	return printed;
+}
+
+#define SCA_MMAP_FLAGS syscall_arg__scnprintf_mmap_flags
+
+static size_t syscall_arg__scnprintf_madvise_behavior(char *bf, size_t size, unsigned long arg)
+{
+	int behavior = arg;
+
+	switch (behavior) {
+#define	P_MADV_BHV(n) case MADV_##n: return scnprintf(bf, size, #n)
+	P_MADV_BHV(NORMAL);
+	P_MADV_BHV(RANDOM);
+	P_MADV_BHV(SEQUENTIAL);
+	P_MADV_BHV(WILLNEED);
+	P_MADV_BHV(DONTNEED);
+	P_MADV_BHV(REMOVE);
+	P_MADV_BHV(DONTFORK);
+	P_MADV_BHV(DOFORK);
+	P_MADV_BHV(HWPOISON);
+#ifdef MADV_SOFT_OFFLINE
+	P_MADV_BHV(SOFT_OFFLINE);
+#endif
+	P_MADV_BHV(MERGEABLE);
+	P_MADV_BHV(UNMERGEABLE);
+	P_MADV_BHV(HUGEPAGE);
+	P_MADV_BHV(NOHUGEPAGE);
+#ifdef MADV_DONTDUMP
+	P_MADV_BHV(DONTDUMP);
+#endif
+#ifdef MADV_DODUMP
+	P_MADV_BHV(DODUMP);
+#endif
+#undef P_MADV_PHV
+	default: break;
+	}
+
+	return scnprintf(bf, size, "%#x", behavior);
+}
+
+#define SCA_MADV_BHV syscall_arg__scnprintf_madvise_behavior
 
 static struct syscall_fmt {
 	const char *name;
 	const char *alias;
+	size_t	   (*arg_scnprintf[6])(char *bf, size_t size, unsigned long arg);
 	bool	   errmsg;
 	bool	   timeout;
+	bool	   hexret;
 } syscall_fmts[] = {
 	{ .name	    = "access",	    .errmsg = true, },
 	{ .name	    = "arch_prctl", .errmsg = true, .alias = "prctl", },
+	{ .name	    = "brk",	    .hexret = true,
+	  .arg_scnprintf = { [0] = SCA_HEX, /* brk */ }, },
+	{ .name	    = "mmap",	    .hexret = true, },
 	{ .name	    = "connect",    .errmsg = true, },
 	{ .name	    = "fstat",	    .errmsg = true, .alias = "newfstat", },
 	{ .name	    = "fstatat",    .errmsg = true, .alias = "newfstatat", },
 	{ .name	    = "futex",	    .errmsg = true, },
+	{ .name	    = "ioctl",	    .errmsg = true,
+	  .arg_scnprintf = { [2] = SCA_HEX, /* arg */ }, },
+	{ .name	    = "lstat",	    .errmsg = true, .alias = "newlstat", },
+	{ .name     = "madvise",    .errmsg = true,
+	  .arg_scnprintf = { [0] = SCA_HEX,	 /* start */
+			     [2] = SCA_MADV_BHV, /* behavior */ }, },
+	{ .name	    = "mmap",	    .hexret = true,
+	  .arg_scnprintf = { [0] = SCA_HEX,	  /* addr */
+			     [2] = SCA_MMAP_PROT, /* prot */
+			     [3] = SCA_MMAP_FLAGS, /* flags */ }, },
+	{ .name	    = "mprotect",   .errmsg = true,
+	  .arg_scnprintf = { [0] = SCA_HEX, /* start */
+			     [2] = SCA_MMAP_PROT, /* prot */ }, },
+	{ .name	    = "mremap",	    .hexret = true,
+	  .arg_scnprintf = { [0] = SCA_HEX, /* addr */
+			     [4] = SCA_HEX, /* new_addr */ }, },
+	{ .name	    = "munmap",	    .errmsg = true,
+	  .arg_scnprintf = { [0] = SCA_HEX, /* addr */ }, },
 	{ .name	    = "open",	    .errmsg = true, },
 	{ .name	    = "poll",	    .errmsg = true, .timeout = true, },
 	{ .name	    = "ppoll",	    .errmsg = true, .timeout = true, },
+	{ .name	    = "pread",	    .errmsg = true, .alias = "pread64", },
+	{ .name	    = "pwrite",	    .errmsg = true, .alias = "pwrite64", },
 	{ .name	    = "read",	    .errmsg = true, },
 	{ .name	    = "recvfrom",   .errmsg = true, },
 	{ .name	    = "select",	    .errmsg = true, .timeout = true, },
 	{ .name	    = "socket",	    .errmsg = true, },
 	{ .name	    = "stat",	    .errmsg = true, .alias = "newstat", },
+	{ .name	    = "uname",	    .errmsg = true, .alias = "newuname", },
 };
 
 static int syscall_fmt__cmp(const void *name, const void *fmtp)
@@ -50,6 +190,7 @@ struct syscall {
 	const char	    *name;
 	bool		    filtered;
 	struct syscall_fmt  *fmt;
+	size_t		    (**arg_scnprintf)(char *bf, size_t size, unsigned long arg);
 };
 
 static size_t fprintf_duration(unsigned long t, FILE *fp)
@@ -63,7 +204,7 @@ static size_t fprintf_duration(unsigned long t, FILE *fp)
 		printed += color_fprintf(fp, PERF_COLOR_YELLOW, "%6.3f ms", duration);
 	else
 		printed += color_fprintf(fp, PERF_COLOR_NORMAL, "%6.3f ms", duration);
-	return printed + fprintf(stdout, "): ");
+	return printed + fprintf(fp, "): ");
 }
 
 struct thread_trace {
@@ -80,7 +221,7 @@ static struct thread_trace *thread_trace__new(void)
 	return zalloc(sizeof(struct thread_trace));
 }
 
-static struct thread_trace *thread__trace(struct thread *thread)
+static struct thread_trace *thread__trace(struct thread *thread, FILE *fp)
 {
 	struct thread_trace *ttrace;
 
@@ -98,12 +239,13 @@ static struct thread_trace *thread__trace(struct thread *thread)
 
 	return ttrace;
 fail:
-	color_fprintf(stdout, PERF_COLOR_RED,
+	color_fprintf(fp, PERF_COLOR_RED,
 		      "WARNING: not enough memory, dropping samples!\n");
 	return NULL;
 }
 
 struct trace {
+	struct perf_tool	tool;
 	int			audit_machine;
 	struct {
 		int		max;
@@ -112,8 +254,10 @@ struct trace {
 	struct perf_record_opts opts;
 	struct machine		host;
 	u64			base_time;
-	struct strlist		*ev_qualifier;
+	FILE			*output;
 	unsigned long		nr_events;
+	struct strlist		*ev_qualifier;
+	bool			not_ev_qualifier;
 	bool			sched;
 	bool			multiple_threads;
 	double			duration_filter;
@@ -151,13 +295,14 @@ static size_t trace__fprintf_entry_head(struct trace *trace, struct thread *thre
 	return printed;
 }
 
-static int trace__process_event(struct machine *machine, union perf_event *event)
+static int trace__process_event(struct trace *trace, struct machine *machine,
+				union perf_event *event)
 {
 	int ret = 0;
 
 	switch (event->header.type) {
 	case PERF_RECORD_LOST:
-		color_fprintf(stdout, PERF_COLOR_RED,
+		color_fprintf(trace->output, PERF_COLOR_RED,
 			      "LOST %" PRIu64 " events!\n", event->lost.lost);
 		ret = machine__process_lost_event(machine, event);
 	default:
@@ -168,12 +313,13 @@ static int trace__process_event(struct machine *machine, union perf_event *event
 	return ret;
 }
 
-static int trace__tool_process(struct perf_tool *tool __maybe_unused,
+static int trace__tool_process(struct perf_tool *tool,
 			       union perf_event *event,
 			       struct perf_sample *sample __maybe_unused,
 			       struct machine *machine)
 {
-	return trace__process_event(machine, event);
+	struct trace *trace = container_of(tool, struct trace, tool);
+	return trace__process_event(trace, machine, event);
 }
 
 static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
@@ -187,11 +333,11 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
 	machine__create_kernel_maps(&trace->host);
 
 	if (perf_target__has_task(&trace->opts.target)) {
-		err = perf_event__synthesize_thread_map(NULL, evlist->threads,
+		err = perf_event__synthesize_thread_map(&trace->tool, evlist->threads,
 							trace__tool_process,
 							&trace->host);
 	} else {
-		err = perf_event__synthesize_threads(NULL, trace__tool_process,
+		err = perf_event__synthesize_threads(&trace->tool, trace__tool_process,
 						     &trace->host);
 	}
 
@@ -201,6 +347,26 @@ static int trace__symbols_init(struct trace *trace, struct perf_evlist *evlist)
 	return err;
 }
 
+static int syscall__set_arg_fmts(struct syscall *sc)
+{
+	struct format_field *field;
+	int idx = 0;
+
+	sc->arg_scnprintf = calloc(sc->tp_format->format.nr_fields - 1, sizeof(void *));
+	if (sc->arg_scnprintf == NULL)
+		return -1;
+
+	for (field = sc->tp_format->format.fields->next; field; field = field->next) {
+		if (sc->fmt && sc->fmt->arg_scnprintf[idx])
+			sc->arg_scnprintf[idx] = sc->fmt->arg_scnprintf[idx];
+		else if (field->flags & FIELD_IS_POINTER)
+			sc->arg_scnprintf[idx] = syscall_arg__scnprintf_hex;
+		++idx;
+	}
+
+	return 0;
+}
+
 static int trace__read_syscall_info(struct trace *trace, int id)
 {
 	char tp_name[128];
@@ -230,7 +396,10 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 	sc = trace->syscalls.table + id;
 	sc->name = name;
 
-	if (trace->ev_qualifier && !strlist__find(trace->ev_qualifier, name)) {
+	if (trace->ev_qualifier) {
+		bool in = strlist__find(trace->ev_qualifier, name) != NULL;
+
+		if (!(in ^ trace->not_ev_qualifier)) {
 			sc->filtered = true;
 			/*
 			 * No need to do read tracepoint information since this will be
@@ -238,6 +407,7 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 			 */
 			return 0;
 		}
+	}
 
 	sc->fmt  = syscall_fmt__find(sc->name);
 
@@ -249,7 +419,10 @@ static int trace__read_syscall_info(struct trace *trace, int id)
 		sc->tp_format = event_format__new("syscalls", tp_name);
 	}
 
-	return sc->tp_format != NULL ? 0 : -1;
+	if (sc->tp_format == NULL)
+		return -1;
+
+	return syscall__set_arg_fmts(sc);
 }
 
 static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
@@ -263,8 +436,14 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 
 		for (field = sc->tp_format->format.fields->next; field; field = field->next) {
 			printed += scnprintf(bf + printed, size - printed,
-					     "%s%s: %ld", printed ? ", " : "",
-					     field->name, args[i++]);
+					     "%s%s: ", printed ? ", " : "", field->name);
+
+			if (sc->arg_scnprintf && sc->arg_scnprintf[i])
+				printed += sc->arg_scnprintf[i](bf + printed, size - printed, args[i]);
+			else
+				printed += scnprintf(bf + printed, size - printed,
+						     "%ld", args[i]);
+                       ++i;
 		}
 	} else {
 		while (i < 6) {
@@ -288,7 +467,22 @@ static struct syscall *trace__syscall_info(struct trace *trace,
 	int id = perf_evsel__intval(evsel, sample, "id");
 
 	if (id < 0) {
-		printf("Invalid syscall %d id, skipping...\n", id);
+
+		/*
+		 * XXX: Noticed on x86_64, reproduced as far back as 3.0.36, haven't tried
+		 * before that, leaving at a higher verbosity level till that is
+		 * explained. Reproduced with plain ftrace with:
+		 *
+		 * echo 1 > /t/events/raw_syscalls/sys_exit/enable
+		 * grep "NR -1 " /t/trace_pipe
+		 *
+		 * After generating some load on the machine.
+ 		 */
+		if (verbose > 1) {
+			static u64 n;
+			fprintf(trace->output, "Invalid syscall %d id, skipping (%s, %" PRIu64 ") ...\n",
+				id, perf_evsel__name(evsel), ++n);
+		}
 		return NULL;
 	}
 
@@ -302,10 +496,12 @@ static struct syscall *trace__syscall_info(struct trace *trace,
 	return &trace->syscalls.table[id];
 
 out_cant_read:
-	printf("Problems reading syscall %d", id);
+	if (verbose) {
+		fprintf(trace->output, "Problems reading syscall %d", id);
 		if (id <= trace->syscalls.max && trace->syscalls.table[id].name != NULL)
-		printf("(%s)", trace->syscalls.table[id].name);
-	puts(" information");
+			fprintf(trace->output, "(%s)", trace->syscalls.table[id].name);
+		fputs(" information\n", trace->output);
+	}
 	return NULL;
 }
 
@@ -326,13 +522,13 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
 		return 0;
 
 	thread = machine__findnew_thread(&trace->host, sample->tid);
-	ttrace = thread__trace(thread);
+	ttrace = thread__trace(thread, trace->output);
 	if (ttrace == NULL)
 		return -1;
 
 	args = perf_evsel__rawptr(evsel, sample, "args");
 	if (args == NULL) {
-		printf("Problems reading syscall arguments\n");
+		fprintf(trace->output, "Problems reading syscall arguments\n");
 		return -1;
 	}
 
@@ -352,8 +548,8 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
 
 	if (!strcmp(sc->name, "exit_group") || !strcmp(sc->name, "exit")) {
 		if (!trace->duration_filter) {
-			trace__fprintf_entry_head(trace, thread, 1, sample->time, stdout);
-			printf("%-70s\n", ttrace->entry_str);
+			trace__fprintf_entry_head(trace, thread, 1, sample->time, trace->output);
+			fprintf(trace->output, "%-70s\n", ttrace->entry_str);
 		}
 	} else
 		ttrace->entry_pending = true;
@@ -377,7 +573,7 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
 		return 0;
 
 	thread = machine__findnew_thread(&trace->host, sample->tid);
-	ttrace = thread__trace(thread);
+	ttrace = thread__trace(thread, trace->output);
 	if (ttrace == NULL)
 		return -1;
 
@@ -394,28 +590,33 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
 	} else if (trace->duration_filter)
 		goto out;
 
-	trace__fprintf_entry_head(trace, thread, duration, sample->time, stdout);
+	trace__fprintf_entry_head(trace, thread, duration, sample->time, trace->output);
 
 	if (ttrace->entry_pending) {
-		printf("%-70s", ttrace->entry_str);
+		fprintf(trace->output, "%-70s", ttrace->entry_str);
 	} else {
-		printf(" ... [");
-		color_fprintf(stdout, PERF_COLOR_YELLOW, "continued");
-		printf("]: %s()", sc->name);
+		fprintf(trace->output, " ... [");
+		color_fprintf(trace->output, PERF_COLOR_YELLOW, "continued");
+		fprintf(trace->output, "]: %s()", sc->name);
 	}
 
-	if (ret < 0 && sc->fmt && sc->fmt->errmsg) {
+	if (sc->fmt == NULL) {
+signed_print:
+		fprintf(trace->output, ") = %d", ret);
+	} else if (ret < 0 && sc->fmt->errmsg) {
 		char bf[256];
 		const char *emsg = strerror_r(-ret, bf, sizeof(bf)),
 			   *e = audit_errno_to_name(-ret);
 
-		printf(") = -1 %s %s", e, emsg);
-	} else if (ret == 0 && sc->fmt && sc->fmt->timeout)
-		printf(") = 0 Timeout");
+		fprintf(trace->output, ") = -1 %s %s", e, emsg);
+	} else if (ret == 0 && sc->fmt->timeout)
+		fprintf(trace->output, ") = 0 Timeout");
+	else if (sc->fmt->hexret)
+		fprintf(trace->output, ") = %#x", ret);
 	else
-		printf(") = %d", ret);
+		goto signed_print;
 
-	putchar('\n');
+	fputc('\n', trace->output);
 out:
 	ttrace->entry_pending = false;
 
@@ -428,7 +629,7 @@ static int trace__sched_stat_runtime(struct trace *trace, struct perf_evsel *evs
         u64 runtime = perf_evsel__intval(evsel, sample, "runtime");
 	double runtime_ms = (double)runtime / NSEC_PER_MSEC;
 	struct thread *thread = machine__findnew_thread(&trace->host, sample->tid);
-	struct thread_trace *ttrace = thread__trace(thread);
+	struct thread_trace *ttrace = thread__trace(thread, trace->output);
 
 	if (ttrace == NULL)
 		goto out_dump;
@@ -438,7 +639,7 @@ static int trace__sched_stat_runtime(struct trace *trace, struct perf_evsel *evs
 	return 0;
 
 out_dump:
-	printf("%s: comm=%s,pid=%u,runtime=%" PRIu64 ",vruntime=%" PRIu64 ")\n",
+	fprintf(trace->output, "%s: comm=%s,pid=%u,runtime=%" PRIu64 ",vruntime=%" PRIu64 ")\n",
 	       evsel->name,
 	       perf_evsel__strval(evsel, sample, "comm"),
 	       (pid_t)perf_evsel__intval(evsel, sample, "pid"),
@@ -456,32 +657,32 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 	const bool forks = argc > 0;
 
 	if (evlist == NULL) {
-		printf("Not enough memory to run!\n");
+		fprintf(trace->output, "Not enough memory to run!\n");
 		goto out;
 	}
 
 	if (perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_enter", trace__sys_enter) ||
 	    perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_exit", trace__sys_exit)) {
-		printf("Couldn't read the raw_syscalls tracepoints information!\n");
+		fprintf(trace->output, "Couldn't read the raw_syscalls tracepoints information!\n");
 		goto out_delete_evlist;
 	}
 
 	if (trace->sched &&
 	    perf_evlist__add_newtp(evlist, "sched", "sched_stat_runtime",
 				   trace__sched_stat_runtime)) {
-		printf("Couldn't read the sched_stat_runtime tracepoint information!\n");
+		fprintf(trace->output, "Couldn't read the sched_stat_runtime tracepoint information!\n");
 		goto out_delete_evlist;
 	}
 
 	err = perf_evlist__create_maps(evlist, &trace->opts.target);
 	if (err < 0) {
-		printf("Problems parsing the target to trace, check your options!\n");
+		fprintf(trace->output, "Problems parsing the target to trace, check your options!\n");
 		goto out_delete_evlist;
 	}
 
 	err = trace__symbols_init(trace, evlist);
 	if (err < 0) {
-		printf("Problems initializing symbol libraries!\n");
+		fprintf(trace->output, "Problems initializing symbol libraries!\n");
 		goto out_delete_maps;
 	}
 
@@ -494,20 +695,20 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 		err = perf_evlist__prepare_workload(evlist, &trace->opts.target,
 						    argv, false, false);
 		if (err < 0) {
-			printf("Couldn't run the workload!\n");
+			fprintf(trace->output, "Couldn't run the workload!\n");
 			goto out_delete_maps;
 		}
 	}
 
 	err = perf_evlist__open(evlist);
 	if (err < 0) {
-		printf("Couldn't create the events: %s\n", strerror(errno));
+		fprintf(trace->output, "Couldn't create the events: %s\n", strerror(errno));
 		goto out_delete_maps;
 	}
 
 	err = perf_evlist__mmap(evlist, UINT_MAX, false);
 	if (err < 0) {
-		printf("Couldn't mmap the events: %s\n", strerror(errno));
+		fprintf(trace->output, "Couldn't mmap the events: %s\n", strerror(errno));
 		goto out_close_evlist;
 	}
 
@@ -532,7 +733,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 
 			err = perf_evlist__parse_sample(evlist, event, &sample);
 			if (err) {
-				printf("Can't parse sample, err = %d, skipping...\n", err);
+				fprintf(trace->output, "Can't parse sample, err = %d, skipping...\n", err);
 				continue;
 			}
 
@@ -540,18 +741,18 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 				trace->base_time = sample.time;
 
 			if (type != PERF_RECORD_SAMPLE) {
-				trace__process_event(&trace->host, event);
+				trace__process_event(trace, &trace->host, event);
 				continue;
 			}
 
 			evsel = perf_evlist__id2evsel(evlist, sample.id);
 			if (evsel == NULL) {
-				printf("Unknown tp ID %" PRIu64 ", skipping...\n", sample.id);
+				fprintf(trace->output, "Unknown tp ID %" PRIu64 ", skipping...\n", sample.id);
 				continue;
 			}
 
 			if (sample.raw_data == NULL) {
-				printf("%s sample with no payload for tid: %d, cpu %d, raw_size=%d, skipping...\n",
+				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);
 				continue;
@@ -640,6 +841,23 @@ static int trace__set_duration(const struct option *opt, const char *str,
 	return 0;
 }
 
+static int trace__open_output(struct trace *trace, const char *filename)
+{
+	struct stat st;
+
+	if (!stat(filename, &st) && st.st_size) {
+		char oldname[PATH_MAX];
+
+		scnprintf(oldname, sizeof(oldname), "%s.old", filename);
+		unlink(oldname);
+		rename(filename, oldname);
+	}
+
+	trace->output = fopen(filename, "w");
+
+	return trace->output == NULL ? -errno : 0;
+}
+
 int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	const char * const trace_usage[] = {
@@ -662,29 +880,33 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 			.no_delay      = true,
 			.mmap_pages    = 1024,
 		},
+		.output = stdout,
 	};
+	const char *output_name = NULL;
 	const char *ev_qualifier_str = NULL;
 	const struct option trace_options[] = {
 	OPT_STRING('e', "expr", &ev_qualifier_str, "expr",
 		    "list of events to trace"),
+	OPT_STRING('o', "output", &output_name, "file", "output file name"),
 	OPT_STRING('p', "pid", &trace.opts.target.pid, "pid",
 		    "trace events on existing process id"),
-	OPT_STRING(0, "tid", &trace.opts.target.tid, "tid",
+	OPT_STRING('t', "tid", &trace.opts.target.tid, "tid",
 		    "trace events on existing thread id"),
-	OPT_BOOLEAN(0, "all-cpus", &trace.opts.target.system_wide,
+	OPT_BOOLEAN('a', "all-cpus", &trace.opts.target.system_wide,
 		    "system-wide collection from all CPUs"),
-	OPT_STRING(0, "cpu", &trace.opts.target.cpu_list, "cpu",
+	OPT_STRING('C', "cpu", &trace.opts.target.cpu_list, "cpu",
 		    "list of cpus to monitor"),
-	OPT_BOOLEAN(0, "no-inherit", &trace.opts.no_inherit,
+	OPT_BOOLEAN('i', "no-inherit", &trace.opts.no_inherit,
 		    "child tasks do not inherit counters"),
-	OPT_UINTEGER(0, "mmap-pages", &trace.opts.mmap_pages,
+	OPT_UINTEGER('m', "mmap-pages", &trace.opts.mmap_pages,
 		     "number of mmap data pages"),
-	OPT_STRING(0, "uid", &trace.opts.target.uid_str, "user",
+	OPT_STRING('u', "uid", &trace.opts.target.uid_str, "user",
 		   "user to profile"),
 	OPT_CALLBACK(0, "duration", &trace, "float",
 		     "show only events with duration > N.M ms",
 		     trace__set_duration),
 	OPT_BOOLEAN(0, "sched", &trace.sched, "show blocking scheduler events"),
+	OPT_INCR('v', "verbose", &verbose, "be more verbose"),
 	OPT_END()
 	};
 	int err;
@@ -692,26 +914,41 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 
 	argc = parse_options(argc, argv, trace_options, trace_usage, 0);
 
+	if (output_name != NULL) {
+		err = trace__open_output(&trace, output_name);
+		if (err < 0) {
+			perror("failed to create output file");
+			goto out;
+		}
+	}
+
 	if (ev_qualifier_str != NULL) {
-		trace.ev_qualifier = strlist__new(true, ev_qualifier_str);
+		const char *s = ev_qualifier_str;
+
+		trace.not_ev_qualifier = *s == '!';
+		if (trace.not_ev_qualifier)
+			++s;
+		trace.ev_qualifier = strlist__new(true, s);
 		if (trace.ev_qualifier == NULL) {
-			puts("Not enough memory to parse event qualifier");
-			return -ENOMEM;
+			fputs("Not enough memory to parse event qualifier",
+			      trace.output);
+			err = -ENOMEM;
+			goto out_close;
 		}
 	}
 
 	err = perf_target__validate(&trace.opts.target);
 	if (err) {
 		perf_target__strerror(&trace.opts.target, err, bf, sizeof(bf));
-		printf("%s", bf);
-		return err;
+		fprintf(trace.output, "%s", bf);
+		goto out_close;
 	}
 
 	err = perf_target__parse_uid(&trace.opts.target);
 	if (err) {
 		perf_target__strerror(&trace.opts.target, err, bf, sizeof(bf));
-		printf("%s", bf);
-		return err;
+		fprintf(trace.output, "%s", bf);
+		goto out_close;
 	}
 
 	if (!argc && perf_target__none(&trace.opts.target))
@@ -720,7 +957,11 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 	err = trace__run(&trace, argc, argv);
 
 	if (trace.sched && !err)
-		trace__fprintf_thread_summary(&trace, stdout);
+		trace__fprintf_thread_summary(&trace, trace.output);
 
+out_close:
+	if (output_name != NULL)
+		fclose(trace.output);
+out:
 	return err;
 }

tools/perf/util/evlist.c

@@ -14,6 +14,7 @@
 #include "target.h"
 #include "evlist.h"
 #include "evsel.h"
+#include "debug.h"
 #include <unistd.h>
 
 #include "parse-events.h"
@@ -486,6 +487,7 @@ static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, int prot, int m
 	int nr_cpus = cpu_map__nr(evlist->cpus);
 	int nr_threads = thread_map__nr(evlist->threads);
 
+	pr_debug2("perf event ring buffer mmapped per cpu\n");
 	for (cpu = 0; cpu < nr_cpus; cpu++) {
 		int output = -1;
 
@@ -524,6 +526,7 @@ static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, int prot, in
 	int thread;
 	int nr_threads = thread_map__nr(evlist->threads);
 
+	pr_debug2("perf event ring buffer mmapped per thread\n");
 	for (thread = 0; thread < nr_threads; thread++) {
 		int output = -1;
 

tools/perf/util/evsel.c

@@ -13,6 +13,7 @@
 #include <traceevent/event-parse.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/perf_event.h>
+#include <sys/resource.h>
 #include "asm/bug.h"
 #include "evsel.h"
 #include "evlist.h"
@@ -21,6 +22,7 @@
 #include "thread_map.h"
 #include "target.h"
 #include "perf_regs.h"
+#include "debug.h"
 
 static struct {
 	bool sample_id_all;
@@ -861,12 +863,72 @@ static int get_group_fd(struct perf_evsel *evsel, int cpu, int thread)
 	return fd;
 }
 
+#define __PRINT_ATTR(fmt, cast, field)  \
+	fprintf(fp, "  %-19s "fmt"\n", #field, cast attr->field)
+
+#define PRINT_ATTR_U32(field)  __PRINT_ATTR("%u" , , field)
+#define PRINT_ATTR_X32(field)  __PRINT_ATTR("%#x", , field)
+#define PRINT_ATTR_U64(field)  __PRINT_ATTR("%" PRIu64, (uint64_t), field)
+#define PRINT_ATTR_X64(field)  __PRINT_ATTR("%#"PRIx64, (uint64_t), field)
+
+#define PRINT_ATTR2N(name1, field1, name2, field2)	\
+	fprintf(fp, "  %-19s %u    %-19s %u\n",		\
+	name1, attr->field1, name2, attr->field2)
+
+#define PRINT_ATTR2(field1, field2) \
+	PRINT_ATTR2N(#field1, field1, #field2, field2)
+
+static size_t perf_event_attr__fprintf(struct perf_event_attr *attr, FILE *fp)
+{
+	size_t ret = 0;
+
+	ret += fprintf(fp, "%.60s\n", graph_dotted_line);
+	ret += fprintf(fp, "perf_event_attr:\n");
+
+	ret += PRINT_ATTR_U32(type);
+	ret += PRINT_ATTR_U32(size);
+	ret += PRINT_ATTR_X64(config);
+	ret += PRINT_ATTR_U64(sample_period);
+	ret += PRINT_ATTR_U64(sample_freq);
+	ret += PRINT_ATTR_X64(sample_type);
+	ret += PRINT_ATTR_X64(read_format);
+
+	ret += PRINT_ATTR2(disabled, inherit);
+	ret += PRINT_ATTR2(pinned, exclusive);
+	ret += PRINT_ATTR2(exclude_user, exclude_kernel);
+	ret += PRINT_ATTR2(exclude_hv, exclude_idle);
+	ret += PRINT_ATTR2(mmap, comm);
+	ret += PRINT_ATTR2(freq, inherit_stat);
+	ret += PRINT_ATTR2(enable_on_exec, task);
+	ret += PRINT_ATTR2(watermark, precise_ip);
+	ret += PRINT_ATTR2(mmap_data, sample_id_all);
+	ret += PRINT_ATTR2(exclude_host, exclude_guest);
+	ret += PRINT_ATTR2N("excl.callchain_kern", exclude_callchain_kernel,
+			    "excl.callchain_user", exclude_callchain_user);
+
+	ret += PRINT_ATTR_U32(wakeup_events);
+	ret += PRINT_ATTR_U32(wakeup_watermark);
+	ret += PRINT_ATTR_X32(bp_type);
+	ret += PRINT_ATTR_X64(bp_addr);
+	ret += PRINT_ATTR_X64(config1);
+	ret += PRINT_ATTR_U64(bp_len);
+	ret += PRINT_ATTR_X64(config2);
+	ret += PRINT_ATTR_X64(branch_sample_type);
+	ret += PRINT_ATTR_X64(sample_regs_user);
+	ret += PRINT_ATTR_U32(sample_stack_user);
+
+	ret += fprintf(fp, "%.60s\n", graph_dotted_line);
+
+	return ret;
+}
+
 static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 			      struct thread_map *threads)
 {
 	int cpu, thread;
 	unsigned long flags = 0;
 	int pid = -1, err;
+	enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;
 
 	if (evsel->fd == NULL &&
 	    perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
@@ -884,6 +946,9 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 	if (perf_missing_features.sample_id_all)
 		evsel->attr.sample_id_all = 0;
 
+	if (verbose >= 2)
+		perf_event_attr__fprintf(&evsel->attr, stderr);
+
 	for (cpu = 0; cpu < cpus->nr; cpu++) {
 
 		for (thread = 0; thread < threads->nr; thread++) {
@@ -893,6 +958,9 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 				pid = threads->map[thread];
 
 			group_fd = get_group_fd(evsel, cpu, thread);
+retry_open:
+			pr_debug2("perf_event_open: pid %d  cpu %d  group_fd %d  flags %#lx\n",
+				  pid, cpus->map[cpu], group_fd, flags);
 
 			FD(evsel, cpu, thread) = sys_perf_event_open(&evsel->attr,
 								     pid,
@@ -902,12 +970,37 @@ static int __perf_evsel__open(struct perf_evsel *evsel, struct cpu_map *cpus,
 				err = -errno;
 				goto try_fallback;
 			}
+			set_rlimit = NO_CHANGE;
 		}
 	}
 
 	return 0;
 
 try_fallback:
+	/*
+	 * perf stat needs between 5 and 22 fds per CPU. When we run out
+	 * of them try to increase the limits.
+	 */
+	if (err == -EMFILE && set_rlimit < INCREASED_MAX) {
+		struct rlimit l;
+		int old_errno = errno;
+
+		if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
+			if (set_rlimit == NO_CHANGE)
+				l.rlim_cur = l.rlim_max;
+			else {
+				l.rlim_cur = l.rlim_max + 1000;
+				l.rlim_max = l.rlim_cur;
+			}
+			if (setrlimit(RLIMIT_NOFILE, &l) == 0) {
+				set_rlimit++;
+				errno = old_errno;
+				goto retry_open;
+			}
+		}
+		errno = old_errno;
+	}
+
 	if (err != -EINVAL || cpu > 0 || thread > 0)
 		goto out_close;
 

tools/perf/util/machine.c

@@ -253,7 +253,8 @@ void machines__set_id_hdr_size(struct machines *machines, u16 id_hdr_size)
 	return;
 }
 
-static struct thread *__machine__findnew_thread(struct machine *machine, pid_t tid,
+static struct thread *__machine__findnew_thread(struct machine *machine,
+						pid_t pid, pid_t tid,
 						bool create)
 {
 	struct rb_node **p = &machine->threads.rb_node;
@@ -265,8 +266,11 @@ static struct thread *__machine__findnew_thread(struct machine *machine, pid_t t
 	 * so most of the time we dont have to look up
 	 * the full rbtree:
 	 */
-	if (machine->last_match && machine->last_match->tid == tid)
+	if (machine->last_match && machine->last_match->tid == tid) {
+		if (pid && pid != machine->last_match->pid_)
+			machine->last_match->pid_ = pid;
 		return machine->last_match;
+	}
 
 	while (*p != NULL) {
 		parent = *p;
@@ -274,6 +278,8 @@ static struct thread *__machine__findnew_thread(struct machine *machine, pid_t t
 
 		if (th->tid == tid) {
 			machine->last_match = th;
+			if (pid && pid != th->pid_)
+				th->pid_ = pid;
 			return th;
 		}
 
@@ -286,7 +292,7 @@ static struct thread *__machine__findnew_thread(struct machine *machine, pid_t t
 	if (!create)
 		return NULL;
 
-	th = thread__new(tid);
+	th = thread__new(pid, tid);
 	if (th != NULL) {
 		rb_link_node(&th->rb_node, parent, p);
 		rb_insert_color(&th->rb_node, &machine->threads);
@@ -298,12 +304,12 @@ static struct thread *__machine__findnew_thread(struct machine *machine, pid_t t
 
 struct thread *machine__findnew_thread(struct machine *machine, pid_t tid)
 {
-	return __machine__findnew_thread(machine, tid, true);
+	return __machine__findnew_thread(machine, 0, tid, true);
 }
 
 struct thread *machine__find_thread(struct machine *machine, pid_t tid)
 {
-	return __machine__findnew_thread(machine, tid, false);
+	return __machine__findnew_thread(machine, 0, tid, false);
 }
 
 int machine__process_comm_event(struct machine *machine, union perf_event *event)
@@ -1031,11 +1037,27 @@ int machine__process_mmap_event(struct machine *machine, union perf_event *event
 	return 0;
 }
 
+static void machine__remove_thread(struct machine *machine, struct thread *th)
+{
+	machine->last_match = NULL;
+	rb_erase(&th->rb_node, &machine->threads);
+	/*
+	 * We may have references to this thread, for instance in some hist_entry
+	 * instances, so just move them to a separate list.
+	 */
+	list_add_tail(&th->node, &machine->dead_threads);
+}
+
 int machine__process_fork_event(struct machine *machine, union perf_event *event)
 {
-	struct thread *thread = machine__findnew_thread(machine, event->fork.tid);
+	struct thread *thread = machine__find_thread(machine, event->fork.tid);
 	struct thread *parent = machine__findnew_thread(machine, event->fork.ptid);
 
+	/* if a thread currently exists for the thread id remove it */
+	if (thread != NULL)
+		machine__remove_thread(machine, thread);
+
+	thread = machine__findnew_thread(machine, event->fork.tid);
 	if (dump_trace)
 		perf_event__fprintf_task(event, stdout);
 
@@ -1048,18 +1070,8 @@ int machine__process_fork_event(struct machine *machine, union perf_event *event
 	return 0;
 }
 
-static void machine__remove_thread(struct machine *machine, struct thread *th)
-{
-	machine->last_match = NULL;
-	rb_erase(&th->rb_node, &machine->threads);
-	/*
-	 * We may have references to this thread, for instance in some hist_entry
-	 * instances, so just move them to a separate list.
-	 */
-	list_add_tail(&th->node, &machine->dead_threads);
-}
-
-int machine__process_exit_event(struct machine *machine, union perf_event *event)
+int machine__process_exit_event(struct machine *machine __maybe_unused,
+				union perf_event *event)
 {
 	struct thread *thread = machine__find_thread(machine, event->fork.tid);
 
@@ -1067,7 +1079,7 @@ int machine__process_exit_event(struct machine *machine, union perf_event *event
 		perf_event__fprintf_task(event, stdout);
 
 	if (thread != NULL)
-		machine__remove_thread(machine, thread);
+		thread__exited(thread);
 
 	return 0;
 }

tools/perf/util/python.c

@@ -8,6 +8,26 @@
 #include "cpumap.h"
 #include "thread_map.h"
 
+/*
+ * Support debug printing even though util/debug.c is not linked.  That means
+ * implementing 'verbose' and 'eprintf'.
+ */
+int verbose;
+
+int eprintf(int level, const char *fmt, ...)
+{
+	va_list args;
+	int ret = 0;
+
+	if (verbose >= level) {
+		va_start(args, fmt);
+		ret = vfprintf(stderr, fmt, args);
+		va_end(args);
+	}
+
+	return ret;
+}
+
 /* Define PyVarObject_HEAD_INIT for python 2.5 */
 #ifndef PyVarObject_HEAD_INIT
 # define PyVarObject_HEAD_INIT(type, size) PyObject_HEAD_INIT(type) size,

tools/perf/util/thread.c

@@ -7,12 +7,13 @@
 #include "util.h"
 #include "debug.h"
 
-struct thread *thread__new(pid_t tid)
+struct thread *thread__new(pid_t pid, pid_t tid)
 {
 	struct thread *self = zalloc(sizeof(*self));
 
 	if (self != NULL) {
 		map_groups__init(&self->mg);
+		self->pid_ = pid;
 		self->tid = tid;
 		self->ppid = -1;
 		self->comm = malloc(32);

tools/perf/util/thread.h

@@ -12,10 +12,12 @@ struct thread {
 		struct list_head node;
 	};
 	struct map_groups	mg;
+	pid_t			pid_; /* Not all tools update this */
 	pid_t			tid;
 	pid_t			ppid;
 	char			shortname[3];
 	bool			comm_set;
+	bool			dead; /* if set thread has exited */
 	char			*comm;
 	int			comm_len;
 
@@ -24,8 +26,12 @@ struct thread {
 
 struct machine;
 
-struct thread *thread__new(pid_t tid);
+struct thread *thread__new(pid_t pid, pid_t tid);
 void thread__delete(struct thread *self);
+static inline void thread__exited(struct thread *thread)
+{
+	thread->dead = true;
+}
 
 int thread__set_comm(struct thread *self, const char *comm);
 int thread__comm_len(struct thread *self);