REPL hangs at startup on windows

[dhoegh]

I have noticed that Julia 0.3.3 REPL sometimes hangs at startup on windows se:

I have seen this on my own computer and some of my colleagues.

[tkelman]

My usual suspect here is HOMEDRIVE or HOMEPATH maybe being on a non-responsive network drive?

[dhoegh]

Hmm I do not have any network drives. But the variables looks weird:

julia> ENV["HOMEDRIVE"]
"C:"

julia> ENV["HOMEPATH"]
"\\Users\\Hoegh"

My guess is ENV["HOMEDRIVE"] should be "C:\\" and ENV["HOMEPATH"]="C:\\Users\\Hoegh" How are those set?

[tkelman]

That looks normal, those are set by your Windows configuration (and some corporate setups have them set to network drives which can cause issues). Looks like that's not the problem here. When you watch in task manager is there any CPU usage, does the memory use stay constant or change over time?

[dhoegh]

It uses one threads CPU=12%. I haven't observed the memory, I will try to look at it when it happens next time.

[axsk]

I am experiencing the same problem since I started using julia months ago.
It seems to happen randomly, around 1 out of 8 times here.
The CPU stays around 25% and memory usage is constant 86MB (whereas a fresh working instance has around 97MB).

I am running Version 0.4.0-dev+2249 (x86_64-w64-mingw32) on Windows 8. It occurs when starting from cygwin as well as from the native cmd shell.

[tkelman]

@axsk is this while you're running some calculation, or immediately on startup?

[axsk]

immediately on startup, as in the screenshot above

[tkelman]

Hmm, thanks. @dhoegh has this happened to you recently? Are you also on Windows 8 by any chance?

[dhoegh]

It has happened recently, but I would probably say 1/20 startups. I am on Windows 7.

[tkelman]

If it's always on x86_64, then this could potentially be an alternate manifestation of #7942, not sure.

[dhoegh]

I and my colleagues have only x86_64 so it is possible.

[tkelman]

32-bit Julia runs just fine in 64 bit Windows. If you have the disk space and the time and wouldn't mind trying out 32-bit Julia for a little while, it would be interesting to see whether or not you ever encounter the same issue there. You can install both 32 and 64 bit Julia in parallel to different locations, you may need to do Pkg.build a few times to switch package binaries back and forth but otherwise it should be comparable.

[axsk]

I am now trying the 32-bit version, and had no freeze so far (around 20 starts so far).

Interestingely the REPL starts up around 7 times so fast:

32 bit	64 bit
0.8s	5.8s

Should I open a new issue for this?

Also I am not able to reproduce the 64bit freeze/hang with julia -P "exit()", so maybe it is connected to IO or something like that?

[tkelman]

Thanks for collecting that info. Are you using the nightlies or release? Is there a sys.dll file under lib/julia?

so maybe it is connected to IO or something like that?

I think @ihnorton had a theory that there might be some race condition somewhere between libuv and codegen, so possibly.

[axsk]

I am now using the nightlies from today. Yes there is that sys.dll.

[tkelman]

Oh right, I never reverted Jameson's commit that put sys.dll back into the 32-bit nightlies, only on release-0.3. So you'll get faster startup with sys.dll, but backtraces will probably be missing line numbers and file names. If you want line numbers and file names in your backtraces, you can delete or rename sys.dll. Hopefully we'll fix all this before 0.4.0 gets released, so you don't have to choose one or the other.

[dhoegh]

I have now observed this on master to:(

[mikewl]

I have experienced this on 0.3 and master too.

Very rarely and only on Haswell in my experience. I have not experienced it on my Ivy-Bridge box at all.

[tkelman]

I feel like this might be the same underlying issue as #7942 and probably not REPL-related at all.

[tkelman]

closing as dupe of #7942