Re: Git and GCC
- From
Nicolas Pitre <nico@cam.org>
- Date
- Dec 6, 2007, 22:30 UTC
- Message-ID
- <alpine.LFD.0.99999.0712061726240.555@xanadu.home>
- In-Reply-To
- <9e4733910712061422w139273c0gf3cfb04c6ba8c509@mail.gmail.com>
On Thu, 6 Dec 2007, Jon Smirl wrote:
Show 29 quoted lines
> On 12/6/07, Nicolas Pitre <nico@cam.org> wrote: > > On Thu, 6 Dec 2007, Jon Smirl wrote: > > > > > On 12/6/07, Nicolas Pitre <nico@cam.org> wrote: > > > > > When I lasted looked at the code, the problem was in evenly dividing > > > > > the work. I was using a four core machine and most of the time one > > > > > core would end up with 3-5x the work of the lightest loaded core. > > > > > Setting pack.threads up to 20 fixed the problem. With a high number of > > > > > threads I was able to get a 4hr pack to finished in something like > > > > > 1:15. > > > > > > > > But as far as I know you didn't try my latest incarnation which has been > > > > available in Git's master branch for a few months already. > > > > > > I've deleted all my giant packs. Using the kernel pack: > > > 4GB Q6600 > > > > > > Using the current thread pack code I get these results. > > > > > > The interesting case is the last one. I set it to 15 threads and > > > monitored with 'top'. > > > For 0-60% compression I was at 300% CPU, 60-74% was 200% CPU and > > > 74-100% was 100% CPU. It never used all for cores. The only other > > > things running were top and my desktop. This is the same load > > > balancing problem I observed earlier. > > > > Well, that's possible with a window 25 times larger than the default. > > Why did it never use more than three cores?
You have 648366 objects total, and only 647457 of them are subject to delta compression.
With a window size of 250 and a default thread segment of window * 1000 that means only 3 segments will be distributed to threads, hence only 3 threads with work to do.
Nicolas