[test] Introduce stress sampling allocation profiler mode

Bug: v8:7209
Change-Id: Ia10479d7eea6ef2f352d008e2f4b74e2394ab79b
Cq-Include-Trybots: luci.v8.try:v8_linux64_fyi_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/861623
Commit-Queue: Michał Majewski <majeski@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Ali Ijaz Sheikh <ofrobots@google.com>
Cr-Commit-Position: refs/heads/master@{#50527}

infra/testing/client.v8.pyl

@@ -29,8 +29,12 @@
   ],
   'V8 Linux64 - fyi': [
     {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 1},
+    {'name': 'mjsunit', 'variant': 'stress_sampling', 'shards': 1},
+    {'name': 'webkit', 'variant': 'stress_sampling', 'shards': 1},
   ],
   'V8 Linux64 - debug - fyi': [
     {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 2},
+    {'name': 'mjsunit', 'variant': 'stress_sampling', 'shards': 1},
+    {'name': 'webkit', 'variant': 'stress_sampling', 'shards': 1},
   ],
 }

infra/testing/tryserver.v8.pyl

@@ -10,6 +10,8 @@
 
   'v8_linux64_fyi_rel_ng_triggered': [
     {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 2},
+    {'name': 'mjsunit', 'variant': 'stress_sampling', 'shards': 1},
+    {'name': 'webkit', 'variant': 'stress_sampling', 'shards': 1},
   ],
   'v8_linux64_rel_ng_triggered': [
     {'name': 'v8testing', 'variant': 'minor_mc', 'shards': 1},

src/flag-definitions.h

@@ -588,6 +588,9 @@ DEFINE_INT(frame_count, 1, "number of stack frames inspected by the profiler")
 DEFINE_INT(type_info_threshold, 25,
            "percentage of ICs that must have type info to allow optimization")
 
+DEFINE_INT(stress_sampling_allocation_profiler, 0,
+           "Enables sampling allocation profiler with X as a sample interval")
+
 // Garbage collections flags.
 DEFINE_INT(min_semi_space_size, 0,
            "min size of a semi-space (in MBytes), the new space consists of two"

src/isolate.cc

@@ -2568,6 +2568,10 @@ Isolate::Isolate(bool enable_serializer)
 void Isolate::TearDown() {
   TRACE_ISOLATE(tear_down);
 
+  if (FLAG_stress_sampling_allocation_profiler > 0) {
+    heap_profiler()->StopSamplingHeapProfiler();
+  }
+
   // Temporarily set this isolate as current so that various parts of
   // the isolate can access it in their destructors without having a
   // direct pointer. We don't use Enter/Exit here to avoid
@@ -3034,6 +3038,15 @@ bool Isolate::Init(StartupDeserializer* des) {
 
   if (!FLAG_inline_new) heap_.DisableInlineAllocation();
 
+  if (FLAG_stress_sampling_allocation_profiler > 0) {
+    uint64_t sample_interval = FLAG_stress_sampling_allocation_profiler;
+    int stack_depth = 128;
+    v8::HeapProfiler::SamplingFlags sampling_flags =
+        v8::HeapProfiler::SamplingFlags::kSamplingForceGC;
+    heap_profiler()->StartSamplingHeapProfiler(sample_interval, stack_depth,
+                                               sampling_flags);
+  }
+
   return true;
 }
 

tools/testrunner/local/variants.py

@@ -16,6 +16,8 @@ ALL_VARIANT_FLAGS = {
   # https://chromium-review.googlesource.com/c/452620/ for more discussion.
   "nooptimization": [["--noopt"]],
   "stress_background_compile": [["--background-compile", "--stress-background-compile"]],
+  # Trigger stress sampling allocation profiler with sample interval = 2^14
+  "stress_sampling": [["--stress-sampling-allocation-profiler=16384"]],
   "trusted": [["--no-untrusted-code-mitigations"]],
   "wasm_traps": [["--wasm_trap_handler", "--invoke-weak-callbacks", "--wasm-jit-to-native"]],