CPU profiling hangs on Windows.

[Jane Chen]

Embedding v8 4.6.88.

Seeing a hang on Windows during cpu profiling.  The hang happens in any random place calling v8, such as Isolate::New, Context::New etc.  Running optimized build, my stack doesn't show v8 frames. 

Not sure whether it's relevant, I captured this stack once during a hang but not consistent:

RolloverProtectedTickClock::Now()
TimeTicks::HighResolutionNow()
Compiler::GetLazyCode()

Any pointers?

Thanks!

[Ben Noordhuis]

Hi Jane, is upgrading an option for you? There have been numerous CPU
profiler fixes. In fact, the implementation in ToT is almost
unrecognizable from the one in v4.6.

Aside: since you're grappling regularly with unmaintained versions of
V8, have you considered switching to the V8 that is bundled with
node.js LTS?

- Node.js v4.x LTS ships V8 4.5 and is maintained until April 2018
(and has received a few fixes for issues similar to yours).
- Node.js v6.x will go LTS in two months and ship with V8 5.x, exact
version TBD. It's going to be maintained until April 2019.

[Jane Chen]

Ben,

Thanks for the tip.  I'll look into that option.

In general we are open to upgrade to a later release as long as we don't introduce incompatibilities.  Good to know that certain bug fixes are back-ported with Node.js LTS releases.

Jane

[Jane Chen]

Referring to this thread:

https://groups.google.com/forum/#!searchin/v8-users/profiling$20line$20numbers|sort:relevance/v8-users/C8HEYUx7RFs/l7fJD1ebBAAJ

I changed my code to turn on profiling before compiling the script.  It didn't completely eliminate the hang, and it made it harder to reproduce. 

Are we supposed to always turn on profiling before compiling the script to be profiled?