[dm-devel] Thoughts on removing the remap cache
FUJITA Tomonori
fujita.tomonori at lab.ntt.co.jp
Sat Sep 30 16:27:38 UTC 2006
From: Dan Smith <danms at us.ibm.com>
Subject: Re: [dm-devel] Thoughts on removing the remap cache
Date: Sat, 30 Sep 2006 08:44:26 -0700
> FT> I guess that dbench generates relatively large size I/Os than
> FT> common workloads, which is more sensitive to latency.
>
> Right, that is what I am thinking. However, dbench inside a domU does
> not perform well either. Even running dbench inside a domU, the
> batches that the userspace daemon sees are only about 10 requests,
> compared to several thousand at times when running on bare metal.
>
> FT> Seems that Xen camp is pretty happy with blktap. So dm-userspace
> FT> should be ok with domU. Maybe it's time to try ring buffer stuff
> FT> again. :)
>
> You think that the ring buffer has the potential to be lower latency
> due to fewer memcpy()'s right?
Yeah, though there might be other factors, I guess.
Anyway, could you try the new ring buffer patch that I posted?
More information about the dm-devel
mailing list