msvs_multi_core_compile

[Nico Weber]

Hi,

I discovered today that my z600 needs 40 minutes for a clean build,
which seems way to long. I searched a bit and found that I have to put

{
'variables': {
'msvs_multi_core_compile': 1,
}

into %userprofile%\.gyp\include.gypi (
http://dev.chromium.org/developers/how-tos/build-instructions-windows
) to enable multicore compiles. My build time went from 40 min to 13
min.

Why is this not the default? Are there any cases where this hurts?

Nico

[Bradley Nelson]

Which msvs and os?

It should turn on by default for 2008, I forget why its off for 2005, potentially incorrect build if I recall.

-BradN

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[Nico Weber]

On Wed, Jul 21, 2010 at 3:14 PM, Bradley Nelson <bradn...@google.com> wrote:
> Which msvs and os?

2005 and win7.

[Nico Weber]

On Wed, Jul 21, 2010 at 3:14 PM, Bradley Nelson <bradn...@google.com> wrote:

> Which msvs and os?
> It should turn on by default for 2008, I forget why its off for 2005,
> potentially incorrect build if I recall.

I remember some ancient thread titled "/MP" on chrome-team where
several people claimed they use this without issues.

[Bradley Nelson]

Yeah, 2005 would do it.

(somebody, maybe it was finnur, had found a bug in the version detection logic on win7, which is why I asked about the os).

If I recall /MP fails like 5% of the time or something, which is mainly a problem for the bots.

I suppose we could gate it just on running on the bots?

My sense is a good fraction of the team has switched to 2008, but I'm not sure what %.

-BradN

[Bradley Nelson]

You can always add it to you ~/.gyp/include.gypi

[Dominic Mazzoni]

You're talking about a Release build, right? I can also do a Release build of just Chrome in about 13 minutes. I haven't timed a Debug build in a while, but I think it takes over 30 minutes, does that sound right?

- Dominic

On Wed, Jul 21, 2010 at 3:10 PM, Nico Weber <tha...@chromium.org> wrote:

--

[Nico Weber]

No, I'm talking about a debug build.

[Dominic Mazzoni]

Wow! I'm using VS 2008 on Vista on a Z600. What am I doing wrong?

- Dominic

[Alpha Lam]

What about incremental link? I can never get it working.. even though I'm now running Win7 and VS2008.

Alpha

2010年7月21日15:45 Dominic Mazzoni <dmaz...@chromium.org>:

[Antony Sargent]

Did you turn on hyperthreading in your BIOS? (You should see 16 cores instead of 8 in the task manager). Also, do you have 12GB of ram?

On Wed, Jul 21, 2010 at 3:39 PM, Dominic Mazzoni <dmaz...@chromium.org> wrote:

[Dominic Mazzoni]

On Wed, Jul 21, 2010 at 4:37 PM, Antony Sargent <asar...@chromium.org> wrote:

Did you turn on hyperthreading in your BIOS? (You should see 16 cores instead of 8 in the task manager). Also, do you have 12GB of ram?

Yes and yes.

How long should a release build take?

I added my chromium source directory to the exclude list for Sophos. Any other software that might be slowing it down? I don't use Windows other than for Chrome development, so I might be missing something stupid.

[Antony Sargent]

How long should a release build take?

I added my chromium source directory to the exclude list for Sophos. Any other software that might be slowing it down? I don't use Windows other than for Chrome development, so I might be missing something stupid.

I usually compile in Debug mode, so I'm not sure about Release mode. I just timed a clean Debug build of chrome.exe and it took about 15 minutes on my system (while I had a few other programs running at the same time). 

[Jeremy Orlow]

I've had that flag turned on for all my vista+2005+z600 builds ever and only had corruption maybe 3-4 times total.  (Out of probably 1000's of builds?)  It's hard to say whether that's worth it or not.

Btw, has anyone recently looked to see if 2005 (with the flag on) is still faster than 2008?  You need 2005 to compile WebKit's safari DLL, but I haven't migrated to 2008 yet because last I saw 2005 was 10% faster.

J