Bug 38436 – [Windows] Improve build speed with VS2005EE

• Component: Tools / Tests
• Status: RESOLVED WONTFIX

[Kent Tamura]

[Windows] Improve build speed with VS2005EE

[Kent Tamura]

Created attachment 54881 [details]
Patch

[Kent Tamura]

(In reply to comment #1)
> Created an attachment (id=54881) [details]
> Patch

Without this patch, build-webkit --debug took 42m:33s.
With this patch, it takes 12m:35s on a 4-core machine.

[Sam Weinig]

What does this option do?

[Kent Tamura]

(In reply to comment #3)
> What does this option do?

It enables multi-process build.
http://msdn.microsoft.com/en-us/library/bb385193(v=VS.90).aspx

/MP was not documented for VS2005, and was exposed by VS2008.
You might feel such undocumented option is dangerous.

[Sam Weinig]

How does this compare to using pdevenv?

[Adam Roben (:aroben)]

Comment on attachment 54881 [details]
Patch

What is "VS2005EE"?

My understanding is that /MP doesn't work in conjunction with "minimal rebuild" (/Gm), which we have turned on for Debug builds. It also seems like it would have bad interactions with pdevenv, which forks off multiple cl.exe processes in order to support parallel compilation.

[Kent Tamura]

(In reply to comment #6)
> (From update of attachment 54881 [details])
> What is "VS2005EE"?

I meant Visual Studio 2005 Express Edition.

> My understanding is that /MP doesn't work in conjunction with "minimal rebuild"
> (/Gm), which we have turned on for Debug builds. It also seems like it would
> have bad interactions with pdevenv, which forks off multiple cl.exe processes
> in order to support parallel compilation.

I see.
ok, I withdraw this patch.

[Eric Seidel (no email)]

I thought our visual studio express build doesn't currently use pdevenv?

Seems that we should have some sort of wrapper which uses either or?  Maybe that makes no sense.  In any case, our windows builds are insanely slow and that makes them impossible to keep green.

[Brian Weinstein]

(In reply to comment #8)
> I thought our visual studio express build doesn't currently use pdevenv?
> 
> Seems that we should have some sort of wrapper which uses either or?  Maybe
> that makes no sense.  In any case, our windows builds are insanely slow and
> that makes them impossible to keep green.

That is incorrect. The builders keep up with the other builders in the system, it's the test bots that are the issue. That has nothing to do with pdevenv or Visual Studio.

[Eric Seidel (no email)]

Thank you for the clarification Brian.

[Adam Roben (:aroben)]

(In reply to comment #8)
> I thought our visual studio express build doesn't currently use pdevenv?
> 
> Seems that we should have some sort of wrapper which uses either or?  Maybe
> that makes no sense.

It would definitely be nice to make parallel builds possible for everyone. Bug 37995 is about just that! I don't really have any sense of what the pros/cons are of pdevenv vs. /MP, other than pdevenv working with "minimal rebuild".

By the way, Kent, I wasn't trying to discourage this patch. I was just trying to understand the pros and cons better.