Re: [dm-devel] [PATCH 1/2] dm-userspace: use ring buffer instead of system call

[FUJITA Tomonori <fujita tomonori lab ntt co jp>]

Hey Dan,

Has there been any progress on this?

From: FUJITA Tomonori <fujita tomonori lab ntt co jp>
Subject: Re: [dm-devel] [PATCH 1/2] dm-userspace: use ring buffer instead	of	system call
Date: Fri, 27 Oct 2006 23:36:31 +0900

> From: Dan Smith <danms us ibm com>
> Subject: Re: [dm-devel] [PATCH 1/2] dm-userspace: use ring buffer instead of	system call
> Date: Fri, 27 Oct 2006 07:01:41 -0700
> 
> > FT> It's against on the top of the following patches:
> > 
> > Would you mind sending a patch against a vanilla tree?  I'm having a
> > hard time getting the patches (old and new) to apply cleanly and in
> > the right order.
> 
> No problem. Here's the patch against 2.6.18
> 
> 
> > FT> In my experiments, the ring buffer interface provides 10% better
> > FT> write performance with disktest benchmark, though dbench gives
> > FT> comparable performances (about 340 MB/s).
> > 
> > This is good to hear.  I am interested in testing it in some of my
> > real-life situations where performance is slower due to the high
> > latency.  This mostly affects the boot time of Xen guests.
> > 
> > I have added kernel caching back into my local version (which only
> > adds 200 lines).  It improves Xen guest boot performance
> > significantly, but does not affect dbench performance.  I will be
> > interested to see what kind of performance I can get from your
> > ringbuffer version, as well as possibly a combination of the two.
> 
> I see. I'm looking forward to the results. Then I'll send some other
> patches.