[Mono-devel-list] statistical profiler (hack)
Paolo Molaro
lupus at ximian.com
Thu Aug 19 14:50:54 EDT 2004
People may be interested in this tool to do profiling.
Unlike the current --profiler default profiler, this interfers
very little with the performance of the running application,
but doesn't provide caller info or memory allocation stats.
It has only been tested on my Debian, but it should work on any modern
linux box: the features required are setitimer support and
backtrace_symbols(), a feature of libc which could be made optional.
This tool can be used to have some info also on the time spent in the
runtime, as opposed to just managed code, but this needs
backtrace_symbols support and the version script in mini/Makefile.am
needs to be disabled for more informative results.
Best results on systems with the kernel HZ value of about 1000
(Linux kernels 2.6 have this by default, 2.4 has 100 which is a bit low:
it means the program is sampled only 100 times per second).
There is no option to enable/disable: once the code has been made more
portable I'll design an interface to be able to implement it as a
profiler module.
lupus
--
-----------------------------------------------------------------
lupus at debian.org debian/rules
lupus at ximian.com Monkeys do it better
-------------- next part --------------
Index: mini.c
===================================================================
RCS file: /cvs/public/mono/mono/mini/mini.c,v
retrieving revision 1.283
diff -u -p -r1.283 mini.c
--- mini.c 18 Aug 2004 15:30:14 -0000 1.283
+++ mini.c 19 Aug 2004 17:25:25 -0000
@@ -56,6 +56,8 @@
#include "jit-icalls.c"
+#include <sys/time.h>
+
/*
* this is used to determine when some branch optimizations are possible: we exclude FP compares
* because they have weird semantics with NaNs.
@@ -65,6 +67,7 @@
#define MONO_CHECK_THIS(ins) (cfg->method->signature->hasthis && (ins)->ssa_op == MONO_SSA_LOAD && (ins)->inst_left->inst_c0 == 0)
+static void setup_profiler (void);
gboolean mono_arch_print_tree(MonoInst *tree, int arity);
static gpointer mono_jit_compile_method_with_opt (MonoMethod *method, guint32 opt);
static gpointer mono_jit_compile_method (MonoMethod *method);
@@ -6457,6 +6460,7 @@ mono_thread_start_cb (guint32 tid, gpoin
thread = mono_thread_current ();
if (thread)
thread->jit_data = jit_tls;
+ setup_profiler ();
}
void (*mono_thread_attach_aborted_cb ) (MonoObject *obj) = NULL;
@@ -8093,6 +8107,88 @@ SIG_HANDLER_SIGNATURE (sigusr1_signal_ha
mono_arch_handle_exception (ctx, exc, FALSE);
}
+/* about 10 minutes of samples */
+#define MAX_PROF_SAMPLES (1000*60*10)
+static int prof_counts = 0;
+static int prof_ucounts = 0;
+static gpointer* prof_addresses = NULL;
+static GHashTable *prof_table = NULL;
+
+static int
+compare_methods_prof (gconstpointer a, gconstpointer b)
+{
+ int ca = GPOINTER_TO_UINT (g_hash_table_lookup (prof_table, a));
+ int cb = GPOINTER_TO_UINT (g_hash_table_lookup (prof_table, b));
+ return cb-ca;
+}
+
+static void
+prof_foreach (char *method, gpointer c, gpointer data)
+{
+ GList **list = data;
+ *list = g_list_insert_sorted (*list, method, compare_methods_prof);
+}
+
+static void
+stat_prof_report (void)
+{
+ MonoJitInfo *ji;
+ int count = prof_counts;
+ int i, c;
+ char *mn;
+ char **names;
+ gpointer ip;
+ GList *tmp, *sorted = NULL;
+
+ prof_counts ++;
+ for (i = 0; i < count; ++i) {
+ ip = prof_addresses [i];
+ ji = mono_jit_info_table_find (mono_domain_get (), ip);
+ if (ji) {
+ mn = mono_method_full_name (ji->method, TRUE);
+ } else {
+ char *send;
+ prof_ucounts++;
+ names = backtrace_symbols (&ip, 1);
+ send = strchr (names [0], '+');
+ if (send)
+ *send = 0;
+ send = strchr (names [0], '[');
+ if (send)
+ *send = 0;
+ mn = g_strdup (names [0]);
+ free (names);
+ }
+ c = GPOINTER_TO_UINT (g_hash_table_lookup (prof_table, mn));
+ c++;
+ g_hash_table_insert (prof_table, mn, GUINT_TO_POINTER (c));
+ if (c > 1)
+ g_free (mn);
+ }
+ g_print ("prof counts/unmanaged: %d/%d\n", prof_counts, prof_ucounts);
+ g_hash_table_foreach (prof_table, prof_foreach, &sorted);
+ for (tmp = sorted; tmp; tmp = tmp->next) {
+ double perc;
+ c = GPOINTER_TO_UINT (g_hash_table_lookup (prof_table, tmp->data));
+ perc = c*100.0/count;
+ g_print ("%7d\t%5.2f %% %s\n", c, perc, tmp->data);
+ }
+ g_list_free (sorted);
+}
+
+static void
+SIG_HANDLER_SIGNATURE (sigprof_signal_handler)
+{
+ int pos;
+
+ GET_CONTEXT;
+
+ if (prof_counts >= MAX_PROF_SAMPLES)
+ return;
+ pos = InterlockedIncrement (&prof_counts);
+ prof_addresses [pos - 1] = mono_arch_ip_from_context (ctx);
+}
+
static void
SIG_HANDLER_SIGNATURE (sigquit_signal_handler)
{
@@ -8178,6 +8274,25 @@ mono_runtime_install_handlers (void)
#endif /* PLATFORM_WIN32 */
}
+static void
+setup_profiler (void)
+{
+ struct itimerval itval;
+ static int inited = 0;
+
+ /* about 10 minutes of samples */
+ prof_addresses = g_new0 (gpointer, MAX_PROF_SAMPLES);
+ itval.it_interval.tv_usec = 1000;
+ itval.it_interval.tv_sec = 0;
+ itval.it_value = itval.it_interval;
+ setitimer (ITIMER_PROF, &itval, NULL);
+ if (inited)
+ return;
+ inited = 1;
+ prof_table = g_hash_table_new (g_str_hash, g_str_equal);
+ add_signal_handler (SIGPROF, sigprof_signal_handler);
+}
+
/* mono_jit_create_remoting_trampoline:
* @method: pointer to the method info
*
@@ -8403,6 +8518,7 @@ print_jit_stats (void)
void
mini_cleanup (MonoDomain *domain)
{
+ stat_prof_report ();
/*
* mono_runtime_cleanup() and mono_domain_finalize () need to
* be called early since they need the execution engine still
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