From: Nicolas Pitre <nico@fluxnic.net>
Date: Mon, 12 Apr 2010 15:45:24 GMT
Subject: Re: [PATCH 1/2] index-pack: smarter memory usage when resolving deltas
Message-ID: <alpine.LFD.2.00.1004121141480.7232@xanadu.home>
In-Reply-To: <4BC2BE09.7060809@viscovery.net>

On Mon, 12 Apr 2010, Johannes Sixt wrote:

> Am 4/12/2010 4:57, schrieb Nicolas Pitre:
> > --- a/builtin/index-pack.c
> > +++ b/builtin/index-pack.c
> > @@ -359,34 +359,33 @@ static void *get_data_from_pack(struct object_entry *obj)
> >  {
> >  	off_t from = obj[0].idx.offset + obj[0].hdr_size;
> >  	unsigned long len = obj[1].idx.offset - from;
> > -	unsigned long rdy = 0;
> > -	unsigned char *src, *data;
> > +	unsigned char *data, inbuf[4096];
> 
> With this tiny buffer we make way more pread() calls than we used to,
> right? This hurts emulated pread(), where we do at least 4 syscalls per
> pread(). Shouldn't the buffer be much larger, like min(len,16*4096)?

Well, that is certainly a good compromize.  The buffer would need to be 
malloc()'d and free()'d again though.


Nicolas