Comment #5 on issue 185 by csilvers: add realtime profiling support to
cpuprofiler
http://code.google.com/p/google-perftools/issues/detail?id=185
It's functionally the same:
---
==== //depot/google3/base/profile-handler.cc#2 -
/home/csilvers/google3/base/pro
file-handler.cc ====
--- /tmp/g4-500/cache/depot/google3/base/profile-handler.cc#2 2009-11-04
11:57
:28.000000000 -0500
+++ /home/csilvers/google3/base/profile-handler.cc 2009-11-04
12:21:56.2512
44000 -0500
@@ -56,18 +56,18 @@
// Registers a callback routine to receive profile timer ticks. The
returned
// token is to be used when unregistering this callback and must not be
// deleted by the caller. Registration of the first callback enables the
- // SIGPROF handler.
+ // SIGPROF handler (or SIGALRM if using ITIMER_REAL).
ProfileHandlerToken* RegisterCallback(ProfileHandlerCallback callback,
void* callback_arg);
// Unregisters a previously registered callback. Expects the token
returned
// by the corresponding RegisterCallback routine. Unregistering the last
- // callback disables the SIGPROF handler.
+ // callback disables the SIGPROF handler (or SIGALRM if using
ITIMER_REAL).
void UnregisterCallback(ProfileHandlerToken* token)
NO_THREAD_SAFETY_ANALYSIS;
// Unregisters all the callbacks, stops the timer if shared, disables the
- // SIGPROF handler and clears the timer_sharing_ state.
+ // SIGPROF (or SIGALRM) handler and clears the timer_sharing_ state.
void Reset();
// Gets the current state of profile handler.
@@ -94,12 +94,15 @@
// Initializes the ProfileHandler singleton via GoogleOnceInit.
static void Init();
- // Counts the number of SIGPROF interrupts received.
+ // The number of SIGPROF (or SIGALRM for ITIMER_REAL) interrupts
received.
int64 interrupts_ GUARDED_BY(signal_lock_);
- // SIGPROF interrupt frequency, read-only after construction.
+ // SIGPROF/SIGALRM interrupt frequency, read-only after construction.
int32 frequency_;
+ // ITIMER_PROF (which uses SIGPROF), or ITIMER_REAL (which uses SIGALRM)
+ int timer_type_;
+
// Counts the number of callbacks registered.
int32 callback_count_ GUARDED_BY(control_lock_);
@@ -163,7 +166,7 @@
// Disables (ignores) the timer interrupt signal.
void DisableHandler() EXCLUSIVE_LOCKS_REQUIRED(control_lock_);
- // SIGPROF handler. Iterate over and call all the registered callbacks.
+ // SIGPROF/SIGALRM handler. Iterate over and call all the registered
callback
s.
static void SignalHandler(int sig, siginfo_t* sinfo, void* ucontext);
DISALLOW_EVIL_CONSTRUCTORS(ProfileHandler);
@@ -189,6 +192,9 @@
callback_count_(0),
timer_sharing_(TIMERS_UNTOUCHED) {
SpinLockHolder cl(&control_lock_);
+
+ timer_type_ = (getenv("CPUPROFILE_REALTIME") ? ITIMER_REAL :
ITIMER_PROF);
+
// Get frequency of interrupts (if specified)
char junk;
const char* fr = getenv("CPUPROFILE_FREQUENCY");
@@ -341,18 +347,18 @@
timer.it_interval.tv_sec = 0;
timer.it_interval.tv_usec = 1000000 / frequency_;
timer.it_value = timer.it_interval;
- setitimer(ITIMER_PROF, &timer, 0);
+ setitimer(timer_type_, &timer, 0);
}
void ProfileHandler::StopTimer() {
struct itimerval timer;
memset(&timer, 0, sizeof timer);
- setitimer(ITIMER_PROF, &timer, 0);
+ setitimer(timer_type_, &timer, 0);
}
bool ProfileHandler::IsTimerRunning() {
struct itimerval current_timer;
- RAW_CHECK(0 == getitimer(ITIMER_PROF, ¤t_timer), strerror(errno));
+ RAW_CHECK(0 == getitimer(timer_type_, ¤t_timer), strerror(errno));
return (current_timer.it_value.tv_sec != 0 ||
current_timer.it_value.tv_usec != 0);
}
@@ -362,7 +368,8 @@
sa.sa_sigaction = SignalHandler;
sa.sa_flags = SA_RESTART | SA_SIGINFO;
sigemptyset(&sa.sa_mask);
- RAW_CHECK(sigaction(SIGPROF, &sa, NULL) == 0, strerror(errno));
+ const int signal_number = (timer_type_ == ITIMER_PROF ? SIGPROF :
SIGALRM);
+ RAW_CHECK(sigaction(signal_number, &sa, NULL) == 0, strerror(errno));
}
void ProfileHandler::DisableHandler() {
@@ -370,7 +377,8 @@
sa.sa_handler = SIG_IGN;
sa.sa_flags = SA_RESTART;
sigemptyset(&sa.sa_mask);
- RAW_CHECK(sigaction(SIGPROF, &sa, NULL) == 0, strerror(errno));
+ const int signal_number = (timer_type_ == ITIMER_PROF ? SIGPROF :
SIGALRM);
+ RAW_CHECK(sigaction(signal_number, &sa, NULL) == 0, strerror(errno));
}
void ProfileHandler::SignalHandler(int sig, siginfo_t* sinfo, void*
ucontext) {
---
I also updated the documentation. :-)
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