Add support for CPUPROFILE_TIMER_SIGNAL environment variable.
Which both enables per-thread timers and allows the signal number for
the timer to be selected.
[alk@tut.by: reformatted commit message for subject line length]
Signed-off-by: Aliaksey Kandratsenka <alk@tut.by>
diff --git a/src/profile-handler.cc b/src/profile-handler.cc
index 1518ed4..66c9d74 100644
--- a/src/profile-handler.cc
+++ b/src/profile-handler.cc
@@ -147,6 +147,9 @@
// ITIMER_PROF (which uses SIGPROF), or ITIMER_REAL (which uses SIGALRM)
int timer_type_;
+ // Signal number for timer signal.
+ int signal_number_;
+
// Counts the number of callbacks registered.
int32 callback_count_ GUARDED_BY(control_lock_);
@@ -286,7 +289,8 @@
}
}
-static void StartLinuxThreadTimer(int timer_type, int32 frequency, pthread_key_t timer_key) {
+static void StartLinuxThreadTimer(int timer_type, int signal_number,
+ int32 frequency, pthread_key_t timer_key) {
int rv;
struct sigevent sevp;
timer_t timerid;
@@ -294,7 +298,6 @@
memset(&sevp, 0, sizeof(sevp));
sevp.sigev_notify = SIGEV_THREAD_ID;
sevp._sigev_un._tid = sys_gettid();
- const int signal_number = (timer_type == ITIMER_PROF ? SIGPROF : SIGALRM);
sevp.sigev_signo = signal_number;
clockid_t clock = CLOCK_THREAD_CPUTIME_ID;
if (timer_type == ITIMER_REAL) {
@@ -348,6 +351,7 @@
SpinLockHolder cl(&control_lock_);
timer_type_ = (getenv("CPUPROFILE_REALTIME") ? ITIMER_REAL : ITIMER_PROF);
+ signal_number_ = (timer_type_ == ITIMER_PROF ? SIGPROF : SIGALRM);
// Get frequency of interrupts (if specified)
char junk;
@@ -364,11 +368,35 @@
return;
}
+#if HAVE_LINUX_SIGEV_THREAD_ID
+ // Do this early because we might be overriding signal number.
+
+ const char *per_thread = getenv("CPUPROFILE_PER_THREAD_TIMERS");
+ const char *signal_number = getenv("CPUPROFILE_TIMER_SIGNAL");
+
+ if (per_thread || signal_number) {
+ if (timer_create && pthread_once) {
+ timer_sharing_ = TIMERS_SEPARATE;
+ CreateThreadTimerKey(&thread_timer_key);
+ per_thread_timer_enabled_ = true;
+ // Override signal number if requested.
+ if (signal_number) {
+ signal_number_ = strtol(signal_number, NULL, 0);
+ }
+ } else {
+ RAW_LOG(INFO,
+ "Ignoring CPUPROFILE_PER_THREAD_TIMERS and\n"
+ " CPUPROFILE_TIMER_SIGNAL due to lack of timer_create().\n"
+ " Preload or link to librt.so for this to work");
+ }
+ }
+#endif
+
// If something else is using the signal handler,
// assume it has priority over us and stop.
if (!IsSignalHandlerAvailable()) {
- RAW_LOG(INFO, "Disabling profiler because %s handler is already in use.",
- timer_type_ == ITIMER_REAL ? "SIGALRM" : "SIGPROF");
+ RAW_LOG(INFO, "Disabling profiler because signal %d handler is already in use.",
+ signal_number_);
allowed_ = false;
return;
}
@@ -377,19 +405,6 @@
// should already be ignored.)
DisableHandler();
-#if HAVE_LINUX_SIGEV_THREAD_ID
- if (getenv("CPUPROFILE_PER_THREAD_TIMERS")) {
- if (timer_create && pthread_once) {
- timer_sharing_ = TIMERS_SEPARATE;
- CreateThreadTimerKey(&thread_timer_key);
- per_thread_timer_enabled_ = true;
- } else {
- RAW_LOG(INFO,
- "Not enabling linux-per-thread-timers mode due to lack of timer_create."
- " Preload or link to librt.so for this to work");
- }
- }
-#endif
}
ProfileHandler::~ProfileHandler() {
@@ -538,7 +553,7 @@
#if HAVE_LINUX_SIGEV_THREAD_ID
if (per_thread_timer_enabled_) {
- StartLinuxThreadTimer(timer_type_, frequency_, thread_timer_key);
+ StartLinuxThreadTimer(timer_type_, signal_number_, frequency_, thread_timer_key);
return;
}
#endif
@@ -584,8 +599,7 @@
sa.sa_sigaction = SignalHandler;
sa.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&sa.sa_mask);
- const int signal_number = (timer_type_ == ITIMER_PROF ? SIGPROF : SIGALRM);
- RAW_CHECK(sigaction(signal_number, &sa, NULL) == 0, "sigprof (enable)");
+ RAW_CHECK(sigaction(signal_number_, &sa, NULL) == 0, "sigprof (enable)");
}
void ProfileHandler::DisableHandler() {
@@ -596,14 +610,12 @@
sa.sa_handler = SIG_IGN;
sa.sa_flags = SA_RESTART;
sigemptyset(&sa.sa_mask);
- const int signal_number = (timer_type_ == ITIMER_PROF ? SIGPROF : SIGALRM);
- RAW_CHECK(sigaction(signal_number, &sa, NULL) == 0, "sigprof (disable)");
+ RAW_CHECK(sigaction(signal_number_, &sa, NULL) == 0, "sigprof (disable)");
}
bool ProfileHandler::IsSignalHandlerAvailable() {
struct sigaction sa;
- const int signal_number = (timer_type_ == ITIMER_PROF ? SIGPROF : SIGALRM);
- RAW_CHECK(sigaction(signal_number, NULL, &sa) == 0, "is-signal-handler avail");
+ RAW_CHECK(sigaction(signal_number_, NULL, &sa) == 0, "is-signal-handler avail");
// We only take over the handler if the current one is unset.
// It must be SIG_IGN or SIG_DFL, not some other function.
diff --git a/src/tests/profile-handler_unittest.cc b/src/tests/profile-handler_unittest.cc
index e49d23e..72a4640 100644
--- a/src/tests/profile-handler_unittest.cc
+++ b/src/tests/profile-handler_unittest.cc
@@ -212,6 +212,11 @@
timer_separate_ = threads_have_separate_timers();
#if HAVE_LINUX_SIGEV_THREAD_ID
linux_per_thread_timers_mode_ = (getenv("CPUPROFILE_PER_THREAD_TIMERS") != NULL);
+ const char *signal_number = getenv("CPUPROFILE_TIMER_SIGNAL");
+ if (signal_number) {
+ signal_number_ = strtol(signal_number, NULL, 0);
+ linux_per_thread_timers_mode_ = true;
+ }
#endif
Delay(kTimerResetInterval);
}
