node --prof-process does not work on node 8.x

[joseph-jja]

node 8.11.x
mac 10.11.6
uname -a => Darwin FSCAM1VFG8WM 15.6.0 Darwin Kernel Version 15.6.0: Tue Jan 9 20:12:05 PST 2018; root:xnu-3248.73.5~1/RELEASE_X86_64 x86_64

Run your app with node -prof and it generates the isolate* log file(s)

Then run node --prof-process and it either hangs ( 8.11.x ) or spits out the error below (8.12.rc-x)

ReferenceError: printErr is not defined
at TickProcessor.printError (evalmachine.:2770:3)
at TickProcessor.LogReader.processLog_ (evalmachine.:2522:12)
at TickProcessor.LogReader.processLogLine (evalmachine.:2405:10)
at TickProcessor.processLogFile (evalmachine.:2798:10)
at evalmachine.:3980:15
at internal/v8_prof_processor.js:41:28
at NativeModule.compile (bootstrap_node.js:613:7)
at Function.NativeModule.require (bootstrap_node.js:558:18)
at startup (bootstrap_node.js:150:20)
at bootstrap_node.js:625:3

try running node prof process with node 8.11.3 or later on these files. It just hangs after spitting out a bunch of text about code mode events for unknown.

isolate-0x102804600-v8.log
isolate-0x103800000-v8.log

[richardlau]

At a guess, I suspect we need to backport #19285.

[addaleax]

The commit applies cleanly, so I’ve pushed it to v8.x-staging (2ae98ce)

[richardlau]

On a local Linux system I can recreate the issue described with a built from source v8.12.0 using the isolate logs in the OP. Interestingly all tick-processor tests pass though, which suggests a gap in our testing (although tick-processor is in the ignored suites

node/tools/test.py

Lines 1539 to 1552 in 1519657

	# these suites represent special cases that should not be run as part of the
	# default JavaScript test-run, e.g., internet/ requires a network connection,
	# addons/ requires compilation.
	IGNORED_SUITES = [
	'addons',
	'addons-napi',
	'doctool',
	'gc',
	'internet',
	'pummel',
	'test-known-issues',
	'tick-processor',
	'timers'
	]

so I'm not even sure when the last time it was run on v8.x).

With the current v8.x-staging (i.e. with 2ae98ce) the provided isolate logs are processed with errors (which is why printErr was being called) but does not hang.

[mcollina]

I was able to workaround this in 0x by filtering out extremely long lines: davidmarkclements/0x#172.

[joseph-jja]

I finally got around to installing 8.12.0 and I still get this issue. What 8.x is this fixed in, that this issue got closed?

evalmachine.:2770
printErr(str);
^

ReferenceError: printErr is not defined
at TickProcessor.printError (evalmachine.:2770:3)
at TickProcessor.LogReader.processLog_ (evalmachine.:2522:12)
at TickProcessor.LogReader.processLogLine (evalmachine.:2405:10)
at TickProcessor.processLogFile (evalmachine.:2798:10)
at evalmachine.:3980:15
at internal/v8_prof_processor.js:41:28
at NativeModule.compile (bootstrap_node.js:613:7)
at Function.NativeModule.require (bootstrap_node.js:558:18)
at startup (bootstrap_node.js:150:20)
at bootstrap_node.js:625:3
Processing file isolate-0x103000000-v8.log
evalmachine.:2770
printErr(str);
^

ReferenceError: printErr is not defined
at TickProcessor.printError (evalmachine.:2770:3)
at TickProcessor.LogReader.processLog_ (evalmachine.:2522:12)
at TickProcessor.LogReader.processLogLine (evalmachine.:2405:10)
at TickProcessor.processLogFile (evalmachine.:2798:10)
at evalmachine.:3980:15
at internal/v8_prof_processor.js:41:28
at NativeModule.compile (bootstrap_node.js:613:7)
at Function.NativeModule.require (bootstrap_node.js:558:18)
at startup (bootstrap_node.js:150:20)
at bootstrap_node.js:625:3
Processing file isolate-0x103800000-v8.log
evalmachine.:2770
printErr(str);
^

ReferenceError: printErr is not defined
at TickProcessor.printError (evalmachine.:2770:3)
at TickProcessor.LogReader.processLog_ (evalmachine.:2522:12)
at TickProcessor.LogReader.processLogLine (evalmachine.:2405:10)
at TickProcessor.processLogFile (evalmachine.:2798:10)
at evalmachine.:3980:15
at internal/v8_prof_processor.js:41:28
at NativeModule.compile (bootstrap_node.js:613:7)
at Function.NativeModule.require (bootstrap_node.js:558:18)
at startup (bootstrap_node.js:150:20)
at bootstrap_node.js:625:3

[richardlau]

@joseph-jja This issue isn't closed yet. The fix has gone into the v8.x-staging branch but is not in a release.

cc @nodejs/lts

[joseph-jja]

@richardlau ok, your comment with the red closed confused me :)

[Sytten]

Do we know when this will be released? And do we have an alternative until then?

[mcollina]

@nodejs/lts when do you think a new patch release of 8 could be issued?

[darknz]

+1 on a fix for this please
I have found that the files produced by node --prof on 8.12 can be processed under node 11, so that's a possible workaround if testing is required (and both versions are available to the person testing?)

[kwaping]

I'm also affected by this issue. Thanks for the workaround, @darknz!