[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH v2 00/11] curl: fix curl read

From: Fam Zheng
Subject: Re: [Qemu-devel] [PATCH v2 00/11] curl: fix curl read
Date: Wed, 15 May 2013 11:46:36 +0800
User-agent: Mutt/1.5.21 (2010-09-15)

On Tue, 05/14 10:22, Stefan Hajnoczi wrote:
> On Tue, May 14, 2013 at 10:26:19AM +0800, Fam Zheng wrote:
> >  - CURLDataCache holds the user data read from libcurl, it is in a list
> >    ordered by access, the used cache is moved to list head on access, so
> >    the tail element is freed first. BDRVCURLState.cache_quota is the
> >    threshold to start freeing cache.
> Can you explain the need for a cache?
> The guest kernel already does readahead if it wants to.  It can be tuned
> from inside the guest if performance doesn't meet expectations.  The
> block/curl.c-specific cache cannot be tuned from the guest.

The guest may not do well on this. E.g. GRUB sends sequencial 2KB aio
requests loading the kernel of several MBs. This may make the curl
performs horribly to boot a guest from http served iso.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]