Reviewers: Vyacheslav Egorov,
Message:
Please take a look.
Description:
Profiler experiments: interrupt check at function exit
Please review this at https://chromiumcodereview.appspot.com/9432026/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/flag-definitions.h
M src/ia32/full-codegen-ia32.cc
Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index
8a9ae9d84e764673ab19d7b0a22028212206d75e..bec85bfa2a01d5f4a5b8a31b718d31f5771415cc
100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -177,6 +177,8 @@ DEFINE_bool(self_optimization, false,
"primitive functions trigger their own optimization")
DEFINE_bool(count_based_interrupts, false,
"trigger profiler ticks based on counting instead of timing")
+DEFINE_bool(interrupt_at_exit, false,
+ "insert an interrupt check at function exit")
DEFINE_bool(weighted_back_edges, false,
"weight back edges by jump distance for interrupt triggering")
DEFINE_int(interrupt_budget, 10000,
@@ -187,6 +189,7 @@ DEFINE_int(type_info_threshold, 0,
DEFINE_implication(experimental_profiler, watch_ic_patching)
DEFINE_implication(experimental_profiler, self_optimization)
DEFINE_implication(experimental_profiler, count_based_interrupts)
+DEFINE_implication(experimental_profiler, interrupt_at_exit)
DEFINE_implication(experimental_profiler, weighted_back_edges)
DEFINE_bool(trace_opt_verbose, false, "extra verbose compilation tracing")
Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index
98c80cdb4c9fa9bf16530f7706cfc1eb4cc2e565..f5c1521eb9e512f1314c7ac8479a359b05a1da3b
100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -332,7 +332,7 @@ void
FullCodeGenerator::EmitStackCheck(IterationStatement* stmt,
int weight = 1;
if (FLAG_weighted_back_edges) {
ASSERT(back_edge_target->is_bound());
- int distance = masm_->pc_offset() - back_edge_target->pos();
+ int distance = masm_->SizeOfCodeGeneratedSince(back_edge_target);
weight = Min(127, Max(1, distance / 100));
}
__ sub(Operand::Cell(profiling_counter_),
Immediate(Smi::FromInt(weight)));
@@ -389,6 +389,26 @@ void FullCodeGenerator::EmitReturnSequence() {
__ push(eax);
__ CallRuntime(Runtime::kTraceExit, 1);
}
+ if (FLAG_interrupt_at_exit) {
+ // Pretend that the exit is a backwards jump to the entry.
+ int weight = 1;
+ if (FLAG_weighted_back_edges) {
+ int distance = masm_->pc_offset();
+ weight = Min(127, Max(1, distance / 100));
+ }
+ __ sub(Operand::Cell(profiling_counter_),
+ Immediate(Smi::FromInt(weight)));
+ Label ok;
+ __ j(positive, &ok, Label::kNear);
+ __ push(eax);
+ InterruptStub stub;
+ __ CallStub(&stub);
+ __ pop(eax);
+ // Reset the countdown.
+ __ mov(Operand::Cell(profiling_counter_),
+ Immediate(Smi::FromInt(FLAG_interrupt_budget)));
+ __ bind(&ok);
+ }
#ifdef DEBUG
// Add a label for checking the size of the code used for returning.
Label check_exit_codesize;
--
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