lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 18 Jul 2012 16:12:57 +0800 From: Asias He <asias@...hat.com> To: Stefan Hajnoczi <stefanha@...il.com> CC: Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org, linux-aio@...ck.org, kvm@...r.kernel.org, "Michael S. Tsirkin" <mst@...hat.com>, virtualization@...ts.linux-foundation.org, Benjamin LaHaise <bcrl@...ck.org>, Alexander Viro <viro@...iv.linux.org.uk>, linux-fsdevel@...r.kernel.org Subject: Re: [PATCH 0/5] Add vhost-blk support On 07/17/2012 07:11 PM, Stefan Hajnoczi wrote: > On Tue, Jul 17, 2012 at 10:21 AM, Asias He <asias@...hat.com> wrote: >> On 07/17/2012 04:52 PM, Paolo Bonzini wrote: >>> >>> Il 17/07/2012 10:29, Asias He ha scritto: >>>> >>>> So, vhost-blk at least saves ~6 syscalls for us in each request. >>> >>> >>> Are they really 6? If I/O is coalesced by a factor of 3, for example >>> (i.e. each exit processes 3 requests), it's really 2 syscalls per request. >> >> >> Well. I am counting the number of syscalls in one notify and response >> process. Sure the IO can be coalesced. > > Linux AIO also supports batching in io_submit() and io_getevents(). > Depending on the request pattern in the vring when you process it, you > should be able to do better than 1 set of syscalls per host I/O > request. > > Are you taking advantage of that at the moment in your userspace benchmark? OK. I know that batching in io_submit() and io_getevetns(). There was a patch for kvm tool long time ago. Now, both vhost-blk and kvm tool are not taking advantage of that atm. There are issues: e.g. How many number of request we want to batch? Does this batching hurt latency? -- Asias -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists