v8 profiling: 0.11.15 and 0.11.16 give two v8.log files

[Irina Tchernouchina]

Hi,

I have a question concerning V8 profiling.

Starting from 0.11.15, for versions 0.11.15 and 0.11.16, using 

node --prof --log-timer-events --logfile=v8_02_02_15.log

I see two log files created, with names like "isolate-03480048-v8_02_02_15.log"

(Have tried several applications)

My question is why there are more than one file, how to interpret it?

I guess it might somehow be related to several isolates used inside?

However, I noticed, that one of files contain only some activities on start,

 then nothing is going on, while another seems to relate to actual processing.

It is also not possible to set --logfile_per_isolate to false (true by default)

It gives error: Error: illegal value for flag --logfile_per_isolate=false of type bool.

PS I suspect this behavior was introduced by following commit:

685ac09 Fedor Indutny at 10/8/2014 12:34 PM (committed at 10/8/2014 1:44 PM)

src, test: fixup after v8 update

Because of behavior change of some V8 APIs (they mostly became more

    strict), following modules needed to be fixed:

* crypto: duplicate prototype methods are not allowed anymore

* contextify: some TryCatch trickery, the binding was using it

incorrectly

* util: maximum call stack error is now crashing in a different place

Reviewed-By: Trevor Norris 

PR-URL: 

https://github.com/joyent/node/pull/8476

Thanks in advance

[Ben Noordhuis]

I suspect that the second log file is created by the built-in debug
agent, it runs in a separate isolate.

To disable per-isolate logfiles, use --nologfile_per_isolate. You may
get some clutter from the aforementioned debug agent isolate, although
I suspect it will be minimal; it's normally idle when the debugger
isn't running.

[Irina Tchernouchina]

Thank you, indeed running without debug flags produces only one file

Tried the option, it works :)