[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] Asynchronous IO
Hi Priya, I'm generally reading and writing 4KB buffers and haven't done a lot of experimenting with other sizes. I you want to send the source that you are using to test throughput with, I'll take a look at how it performs on my test box and see if I can help sort this out. cheers, a. On 9/9/05, Priya, PM <pm.priya@xxxxxx> wrote: > Hi, > > Thanks for your response. Even I got 52MB/sec when I tried to do IO with > buffer size 1 MB. But if I try to do IO with buffer size 512 Bytes, I am > getting 0.032 MB which is 67 IOPs which is not the expected result. Have > you tried the asynchronosu IO with different IO sizes?? > > I am sure I am using right version of MPT driver in Domain 0. Moreover > the same driver performs better if I do synchronous IO in Domain 0. I am > confused. > > Thanks, > Priya. > > -----Original Message----- > From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx > [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Andrew > Warfield > Sent: Thursday, September 08, 2005 11:11 PM > To: Priya PM > Cc: Ian Pratt; ian.pratt@xxxxxxxxxxxx; Xen-users@xxxxxxxxxxxxxxxxxxx > Subject: Re: [Xen-users] Asynchronous IO > > Hi Priya, > > I regularly use libaio in domain zero as a user-space backend for > other domains and am able to saturate a MPT fusion at about 60MB/s > without trying too hard. I seem to remember seeing a comment about a > recent performance drop on the linux-aio list, possibly from 2.6.11 to > 2.6.12, you might want to take a peek at that. Also, are you sure that > your XenLinux dom0 kernel has your disk driver in it, and that it isn't > deferring to a less-efficient means of accessing the disk? > > a. > > On 9/9/05, Priya PM <pmpriya@xxxxxxxxx> wrote: > > Hi, > > > > I tried the same operation with unstable version too. I have changed > > the IO scheduler to atropos and tried. But no use. I always get the > same results. > > Has anyone checked the Asynchronous IO path using libaio? > > > > It would be very much helpful if you can give me some ideas to proceed > > > further, > > > > Thanks, > > Priya. > > > > > > > > On 9/8/05, Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx> wrote: > > > > I have installed Xen on Linux 2.6.11.10 and i am trying to do > > > > Asynchronous Direct IO on SAS drives. The application which does > > > > the asynchronous direct io on SAS drive is running on Domain 0. > > > > Actually the IOPs what i get for a 512Bytes IO size is 67, but if > > > > i do the same operation on Linux 2.6.11.10 native kernel, i get > > > > 267 IOPs.Can anyone tell me why this huge differnece? Am i missing > > > > > something? In the current setup on Xen, if i do Synchronous IO, > > > > then i am getting 265 IOPs which is expected. So i am wondering > > > > why Asynchronous IO should behave this way? Is there any reason?? > > > > > > That's odd. You might want to try the -unstable tree. I know Andy > > > has used AIO just fine on -unstable. > > > > > > Ian > > > > > > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@xxxxxxxxxxxxxxxxxxx > > http://lists.xensource.com/xen-users > > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-users > > _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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