/* Profiler implementation.
-Copyright (C) 2012 Free Software Foundation, Inc.
+Copyright (C) 2012-2013 Free Software Foundation, Inc.
This file is part of GNU Emacs.
along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
-#include <stdio.h>
-#include <limits.h>
-#include <sys/time.h>
-#include <signal.h>
-#include <setjmp.h>
#include "lisp.h"
+#include "syssignal.h"
+#include "systime.h"
+
+/* Return A + B, but return the maximum fixnum if the result would overflow.
+ Assume A and B are nonnegative and in fixnum range. */
+
+static EMACS_INT
+saturated_add (EMACS_INT a, EMACS_INT b)
+{
+ return min (a + b, MOST_POSITIVE_FIXNUM);
+}
/* Logs. */
}
}
-/* Record the current backtrace in LOG. BASE is a special name for
- describing which the backtrace come from. BASE can be nil. COUNT is
- a number how many times the profiler sees the backtrace at the
- time. ELAPSED is a elapsed time in millisecond that the backtrace
- took. */
+/* Record the current backtrace in LOG. COUNT is the weight of this
+ current backtrace: interrupt counts for CPU, and the allocation
+ size for memory. */
static void
-record_backtrace (log_t *log, size_t count)
+record_backtrace (log_t *log, EMACS_INT count)
{
struct backtrace *backlist = backtrace_list;
Lisp_Object backtrace;
/* Copy the backtrace contents into working memory. */
for (; i < asize && backlist; i++, backlist = backlist->next)
/* FIXME: For closures we should ignore the environment. */
- ASET (backtrace, i, *backlist->function);
+ ASET (backtrace, i, backlist->function);
/* Make sure that unused space of working memory is filled with nil. */
for (; i < asize; i++)
EMACS_UINT hash;
ptrdiff_t j = hash_lookup (log, backtrace, &hash);
if (j >= 0)
- set_hash_value_slot (log, j,
- make_number (count + XINT (HASH_VALUE (log, j))));
+ {
+ EMACS_INT old_val = XINT (HASH_VALUE (log, j));
+ EMACS_INT new_val = saturated_add (old_val, count);
+ set_hash_value_slot (log, j, make_number (new_val));
+ }
else
{ /* BEWARE! hash_put in general can allocate memory.
But currently it only does that if log->next_free is nil. */
}
}
\f
-/* Sample profiler. */
+/* Sampling profiler. */
-/* FIXME: Add support for the CPU profiler in W32. */
-/* FIXME: the sigprof_handler suffers from race-conditions if the signal
- is delivered to a thread other than the main Emacs thread. */
+#ifdef PROFILER_CPU_SUPPORT
-#if defined SIGPROF && defined HAVE_SETITIMER
-#define PROFILER_CPU_SUPPORT
+/* The profiler timer and whether it was properly initialized, if
+ POSIX timers are available. */
+#ifdef HAVE_ITIMERSPEC
+static timer_t profiler_timer;
+static bool profiler_timer_ok;
+#endif
-/* True if sampling profiler is running. */
-static bool profiler_cpu_running;
+/* Status of sampling profiler. */
+static enum profiler_cpu_running
+ { NOT_RUNNING, TIMER_SETTIME_RUNNING, SETITIMER_RUNNING }
+ profiler_cpu_running;
+/* Hash-table log of CPU profiler. */
static Lisp_Object cpu_log;
+
/* Separate counter for the time spent in the GC. */
static EMACS_INT cpu_gc_count;
-/* The current sample interval in millisecond. */
-
-static int current_sample_interval;
+/* The current sampling interval in nanoseconds. */
+static EMACS_INT current_sampling_interval;
-/* Signal handler for sample profiler. */
+/* Signal handler for sampling profiler. */
static void
-sigprof_handler (int signal)
+handle_profiler_signal (int signal)
{
- eassert (HASH_TABLE_P (cpu_log));
- if (backtrace_list && EQ (*backtrace_list->function, Qautomatic_gc))
+ if (backtrace_list && EQ (backtrace_list->function, Qautomatic_gc))
/* Special case the time-count inside GC because the hash-table
code is not prepared to be used while the GC is running.
More specifically it uses ASIZE at many places where it does
not expect the ARRAY_MARK_FLAG to be set. We could try and
harden the hash-table code, but it doesn't seem worth the
effort. */
- cpu_gc_count += current_sample_interval;
+ cpu_gc_count = saturated_add (cpu_gc_count, 1);
else
- record_backtrace (XHASH_TABLE (cpu_log), current_sample_interval);
+ {
+ Lisp_Object oquit;
+ bool saved_pending_signals;
+ EMACS_INT count = 1;
+#ifdef HAVE_ITIMERSPEC
+ if (profiler_timer_ok)
+ {
+ int overruns = timer_getoverrun (profiler_timer);
+ eassert (0 <= overruns);
+ count += overruns;
+ }
+#endif
+ /* record_backtrace uses hash functions that call Fequal, which
+ uses QUIT, which can call malloc, which can cause disaster in
+ a signal handler. So inhibit QUIT. */
+ oquit = Vinhibit_quit;
+ saved_pending_signals = pending_signals;
+ Vinhibit_quit = Qt;
+ pending_signals = 0;
+
+ eassert (HASH_TABLE_P (cpu_log));
+ record_backtrace (XHASH_TABLE (cpu_log), count);
+
+ Vinhibit_quit = oquit;
+ pending_signals = saved_pending_signals;
+ }
+}
+
+static void
+deliver_profiler_signal (int signal)
+{
+ deliver_process_signal (signal, handle_profiler_signal);
+}
+
+static enum profiler_cpu_running
+setup_cpu_timer (Lisp_Object sampling_interval)
+{
+ struct sigaction action;
+ struct itimerval timer;
+ struct timespec interval;
+ int billion = 1000000000;
+
+ if (! RANGED_INTEGERP (1, sampling_interval,
+ (TYPE_MAXIMUM (time_t) < EMACS_INT_MAX / billion
+ ? ((EMACS_INT) TYPE_MAXIMUM (time_t) * billion
+ + (billion - 1))
+ : EMACS_INT_MAX)))
+ return NOT_RUNNING;
+
+ current_sampling_interval = XINT (sampling_interval);
+ interval = make_emacs_time (current_sampling_interval / billion,
+ current_sampling_interval % billion);
+ emacs_sigaction_init (&action, deliver_profiler_signal);
+ sigaction (SIGPROF, &action, 0);
+
+#ifdef HAVE_ITIMERSPEC
+ if (! profiler_timer_ok)
+ {
+ /* System clocks to try, in decreasing order of desirability. */
+ static clockid_t const system_clock[] = {
+#ifdef CLOCK_THREAD_CPUTIME_ID
+ CLOCK_THREAD_CPUTIME_ID,
+#endif
+#ifdef CLOCK_PROCESS_CPUTIME_ID
+ CLOCK_PROCESS_CPUTIME_ID,
+#endif
+#ifdef CLOCK_MONOTONIC
+ CLOCK_MONOTONIC,
+#endif
+ CLOCK_REALTIME
+ };
+ int i;
+ struct sigevent sigev;
+ sigev.sigev_value.sival_ptr = &profiler_timer;
+ sigev.sigev_signo = SIGPROF;
+ sigev.sigev_notify = SIGEV_SIGNAL;
+
+ for (i = 0; i < sizeof system_clock / sizeof *system_clock; i++)
+ if (timer_create (system_clock[i], &sigev, &profiler_timer) == 0)
+ {
+ profiler_timer_ok = 1;
+ break;
+ }
+ }
+
+ if (profiler_timer_ok)
+ {
+ struct itimerspec ispec;
+ ispec.it_value = ispec.it_interval = interval;
+ if (timer_settime (profiler_timer, 0, &ispec, 0) == 0)
+ return TIMER_SETTIME_RUNNING;
+ }
+#endif
+
+#ifdef HAVE_SETITIMER
+ timer.it_value = timer.it_interval = make_timeval (interval);
+ if (setitimer (ITIMER_PROF, &timer, 0) == 0)
+ return SETITIMER_RUNNING;
+#endif
+
+ return NOT_RUNNING;
}
DEFUN ("profiler-cpu-start", Fprofiler_cpu_start, Sprofiler_cpu_start,
1, 1, 0,
doc: /* Start or restart the cpu profiler.
-The cpu profiler will take call-stack samples each SAMPLE-INTERVAL (expressed in milliseconds).
+It takes call-stack samples each SAMPLING-INTERVAL nanoseconds, approximately.
See also `profiler-log-size' and `profiler-max-stack-depth'. */)
- (Lisp_Object sample_interval)
+ (Lisp_Object sampling_interval)
{
- struct sigaction sa;
- struct itimerval timer;
-
if (profiler_cpu_running)
- error ("Sample profiler is already running");
+ error ("CPU profiler is already running");
if (NILP (cpu_log))
{
profiler_max_stack_depth);
}
- current_sample_interval = XINT (sample_interval);
-
- sa.sa_handler = sigprof_handler;
- sa.sa_flags = SA_RESTART;
- sigemptyset (&sa.sa_mask);
- sigaction (SIGPROF, &sa, 0);
-
- timer.it_interval.tv_sec = 0;
- timer.it_interval.tv_usec = current_sample_interval * 1000;
- timer.it_value = timer.it_interval;
- setitimer (ITIMER_PROF, &timer, 0);
-
- profiler_cpu_running = true;
+ profiler_cpu_running = setup_cpu_timer (sampling_interval);
+ if (! profiler_cpu_running)
+ error ("Invalid sampling interval");
return Qt;
}
Return non-nil if the profiler was running. */)
(void)
{
- if (!profiler_cpu_running)
- return Qnil;
- profiler_cpu_running = false;
+ switch (profiler_cpu_running)
+ {
+ case NOT_RUNNING:
+ return Qnil;
+
+#ifdef HAVE_ITIMERSPEC
+ case TIMER_SETTIME_RUNNING:
+ {
+ struct itimerspec disable;
+ memset (&disable, 0, sizeof disable);
+ timer_settime (profiler_timer, 0, &disable, 0);
+ }
+ break;
+#endif
- setitimer (ITIMER_PROF, 0, 0);
+#ifdef HAVE_SETITIMER
+ case SETITIMER_RUNNING:
+ {
+ struct itimerval disable;
+ memset (&disable, 0, sizeof disable);
+ setitimer (ITIMER_PROF, &disable, 0);
+ }
+ break;
+#endif
+ }
+ signal (SIGPROF, SIG_IGN);
+ profiler_cpu_running = NOT_RUNNING;
return Qt;
}
(void)
{
Lisp_Object result = cpu_log;
- /* Here we're making the log visible to Elisp , so it's not safe any
+ /* Here we're making the log visible to Elisp, so it's not safe any
more for our use afterwards since we can't rely on its special
pre-allocated keys anymore. So we have to allocate a new one. */
cpu_log = (profiler_cpu_running
cpu_gc_count = 0;
return result;
}
-#endif /* not defined PROFILER_CPU_SUPPORT */
+#endif /* PROFILER_CPU_SUPPORT */
\f
/* Memory profiler. */
malloc_probe (size_t size)
{
eassert (HASH_TABLE_P (memory_log));
- record_backtrace (XHASH_TABLE (memory_log), size);
+ record_backtrace (XHASH_TABLE (memory_log), min (size, MOST_POSITIVE_FIXNUM));
}
void
profiler_log_size = 10000;
#ifdef PROFILER_CPU_SUPPORT
- profiler_cpu_running = false;
+ profiler_cpu_running = NOT_RUNNING;
cpu_log = Qnil;
staticpro (&cpu_log);
defsubr (&Sprofiler_cpu_start);