This patch exposes a new flag perf_basic_prof_only_functions (disabled by
default) that can be useful for the use-case of running always-on profiling on
long running production jobs.
Original commit
https://github.com/v8/v8/commit/
9da3ab661fe7190fcb99bd99db30cf95913d3659
New flag --perf_basic_prof_only_functions
Restricts linux perf-event code range reporting to functions only (i.e. on
stubs.) While this makes the gathered ticks less accurate, it reduces the
growth of the /tmp/perf-${pid}.map file.
BUG=v8:3453
R=hablich@chromium.org,danno@chromium.org
LOG=N
Review URL: https://codereview.chromium.org/
1292743002
Cr-Commit-Position: refs/heads/master@{#30179}
PR-URL: https://github.com/nodejs/node/pull/3609
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
DEFINE_BOOL(perf_basic_prof, false,
"Enable perf linux profiler (basic support).")
DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space)
+DEFINE_BOOL(perf_basic_prof_only_functions, false,
+ "Only report function code ranges to perf (i.e. no stubs).")
+DEFINE_IMPLICATION(perf_basic_prof_only_functions, perf_basic_prof)
DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__",
"Specify the name of the file for fake gc mmap used in ll_prof")
DEFINE_BOOL(log_internal_timer_events, false, "Time internal events.")
int length) {
DCHECK(code->instruction_start() == code->address() + Code::kHeaderSize);
+ if (FLAG_perf_basic_prof_only_functions &&
+ (code->kind() != Code::FUNCTION &&
+ code->kind() != Code::OPTIMIZED_FUNCTION)) {
+ return;
+ }
+
base::OS::FPrint(perf_output_handle_, "%llx %x %.*s\n",
reinterpret_cast<uint64_t>(code->instruction_start()),
code->instruction_size(), length, name);