Re: Seeing high CPU usage during git-upload-pack

From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: May 9, 2012, 15:11 UTC
Message-ID: <CACsJy8CbaM6UNCT3ZP0=VZE9GhH2eJpgKe-dnGU5ubn_4gS=Pw@mail.gmail.com>
In-Reply-To: <CAPeUw3HCkKKBP6RnZzR0TYOO0hHtJ4_ma-Je4a-xKhPpNPJhHw@mail.gmail.com>

Hi,

I don't see anything private in the mail, so I CC git@vger again. It's a good thing to keep git@vger in the loop because there will be more (experienced) people to help you out.

On Wed, May 9, 2012 at 9:37 PM, David Ebbo <david.ebbo@gmail.com> wrote:

Show 8 quoted lines

> Thanks Duy for your looking at this.
>
> On Wed, May 9, 2012 at 3:37 AM, Nguyen Thai Ngoc Duy <pclouds@gmail.com> wrote:
>>
>> What OS is it run on? What git version?
>>
>
> This is using 1.7.9 on Windows (msysgit).

Ah... msysgit reimplements poll() function, in compat/win32/poll.c. If it goes rouge, you could get an active loop. But this is just my suspicion. I don't know anything about msysgit's poll implementation so I can be completely wrong here.

Show 13 quoted lines

>> How about stopping upload-pack and see where it stops? There's a main
>> loop in upload-pack.c, create_pack_file() that is only active when
>> data comes. I looked but failed to see how it becomes a busywait loop.
>> Maybe you can put some debugging there.
>>
>> Setting env var GIT_TRACE_PACKET and GIT_DEBUG_SEND_PACK before
>> running upload-pack might also help.
>>
>
> I'll try those env vars, and will debug as needed (I haven't done that
> yet, so I'll need to get set up <g>)
>
> Thanks for the pointers!

-- 
Duy