From: Shawn Pearce <spearce@spearce.org>
Date: Tue, 19 Dec 2006 07:26:07 GMT
Subject: Re: cloning the kernel - why long time in "Resolving 313037 deltas"
Message-ID: <20061219072607.GD2511@spearce.org>
In-Reply-To: <Pine.LNX.4.64.0612182248420.3479@woody.osdl.org>

Linus Torvalds <torvalds@osdl.org> wrote:
> 
> 
> On Tue, 19 Dec 2006, Shawn Pearce wrote:
> > 
> > Why isn't git-index-pack doing the same?  Is there some hidden glitch
> > in some OS somewhere that has a problem with overmapping a file and
> > appending into it via write()?  I've done that on Mac OS X, Linux,
> > BSDi, Solaris...  never had a problem.
> 
> It works on modern systems, but at least old HPUX versions had 
> non-coherent mmap() and write(), and POSIX does not guarantee it. And if 
> you ever want to port to Windows, I don't think you should do it.
> 
> Anyway, try the pread() version first, see if that fixes the OS X problem.

I'll give your pread() version a shot.

But right now I'm in the middle of cloning your linux-2.6 git
repository.

It is done downloading the pack and my system is pegged at 100%
CPU while resolving deltas.

ActivityMonitor is showing that I'm spending 94% CPU in the kernel,
which is just insane.  Clearly Mac OS X's kernel cannot gracefully
handle what git-index-pack is currently doing.

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