+#if ENABLE(SAMPLING_REGIONS)
+volatile uintptr_t SamplingRegion::s_currentOrReserved;
+Spectrum<const char*>* SamplingRegion::s_spectrum;
+unsigned long SamplingRegion::s_noneOfTheAbove;
+unsigned SamplingRegion::s_numberOfSamplesSinceDump;
+
+SamplingRegion::Locker::Locker()
+{
+ uintptr_t previous;
+ while (true) {
+ previous = s_currentOrReserved;
+ if (previous & 1) {
+#if OS(UNIX)
+ sched_yield();
+#endif
+ continue;
+ }
+ if (WTF::weakCompareAndSwapUIntPtr(&s_currentOrReserved, previous, previous | 1))
+ break;
+ }
+}
+
+SamplingRegion::Locker::~Locker()
+{
+ // We don't need the CAS, but we do it out of an
+ // abundance of caution (and because it gives us a memory fence, which is
+ // never bad).
+ uintptr_t previous;
+ do {
+ previous = s_currentOrReserved;
+ } while (!WTF::weakCompareAndSwapUIntPtr(&s_currentOrReserved, previous, previous & ~1));
+}
+
+void SamplingRegion::sample()
+{
+ // Make sure we lock s_current.
+ Locker locker;
+
+ // Create a spectrum if we don't have one already.
+ if (!s_spectrum)
+ s_spectrum = new Spectrum<const char*>();
+
+ ASSERT(s_currentOrReserved & 1);
+
+ // Walk the region stack, and record each region we see.
+ SamplingRegion* region = bitwise_cast<SamplingRegion*>(s_currentOrReserved & ~1);
+ if (region) {
+ for (; region; region = region->m_previous)
+ s_spectrum->add(region->m_name);
+ } else
+ s_noneOfTheAbove++;
+
+ if (s_numberOfSamplesSinceDump++ == SamplingThread::s_hertz) {
+ s_numberOfSamplesSinceDump = 0;
+ dumpInternal();
+ }
+}
+
+void SamplingRegion::dump()
+{
+ Locker locker;
+
+ dumpInternal();
+}
+
+void SamplingRegion::dumpInternal()
+{
+ if (!s_spectrum) {
+ dataLogF("\nSamplingRegion: was never sampled.\n\n");
+ return;
+ }
+
+ Vector<Spectrum<const char*>::KeyAndCount> list = s_spectrum->buildList();
+
+ unsigned long total = s_noneOfTheAbove;
+ for (unsigned i = list.size(); i--;)
+ total += list[i].count;
+
+ dataLogF("\nSamplingRegion: sample counts for regions: (%lu samples)\n", total);
+
+ for (unsigned i = list.size(); i--;)
+ dataLogF(" %3.2lf%% %s\n", (100.0 * list[i].count) / total, list[i].key);
+}
+#else // ENABLE(SAMPLING_REGIONS)
+void SamplingRegion::dump() { }
+#endif // ENABLE(SAMPLING_REGIONS)
+
projects / apple / javascriptcore.git / blobdiff