Re: [Qemu-devel] dataplane performance on s390

[Paolo Bonzini]

Il 10/06/2014 20:56, Karl Rister ha scritto:
> On 06/09/2014 08:40 PM, Fam Zheng wrote:
> > On Mon, 06/09 15:43, Karl Rister wrote:
> > > Hi All
> > >
> > > I was asked by our development team to do a performance sniff test of
> > > the
> > > latest dataplane code on s390 and compare it against qemu.git.  Here
> > > is a
> > > brief description of the configuration, the testing done, and then the
> > > results.
> > >
> > > Configuration:
> > >
> > > Host: 26 CPU LPAR, 64GB, 8 zFCP adapters
> > > Guest: 4 VCPU, 1GB, 128 virtio block devices
> > >
> > > Each virtio block device maps to a dm-multipath device in the host
> > > with 8
> > > paths.  Multipath is configured with the service-time policy.  All block
> > > devices are configured to use the deadline IO scheduler.
> > >
> > > Test:
> > >
> > > FIO is used to run 4 scenarios: sequential read, sequential write,
> > > random
> > > read, and random write.  Sequential scenarios use a 128KB request
> > > size and
> > > random scenarios us a 8KB request size.  Each scenario is run with an
> > > increasing number of jobs, from 1 to 128 (powers of 2).  Each job is
> > > bound
> > > to an individual file on an ext3 file system on a virtio device and uses
> > > O_DIRECT, libaio, and iodepth=1.  Each test is run three times for 2
> > > minutes
> > > each, the first iteration (a warmup) is thrown out and the next two
> > > iterations are averaged together.
> > >
> > > Results:
> > >
> > > Baseline: qemu.git 93f94f9018229f146ed6bbe9e5ff72d67e4bd7ab
> > >
> > > Dataplane: bdrv_set_aio_context 0ab50cde71aa27f39b8a3ea4766ff82671adb2a4
> >
> > Hi Karl,
> >
> > Thanks for the results.
> >
> > The throughput differences look minimal, where is the bandwidth
> > saturated in
> > these tests?  And why use iodepth=1, not more?
>
> Hi Fam
>
> Based on previously collected data, the configuration is hitting
> saturation at the following points:
>
> Sequential Read: 128 jobs
> Sequential Write: 32 jobs
> Random Read: 64 jobs
> Random Write: saturation not reached
>
> The iodepth=1 configuration is a somewhat arbitrary choice that is only
> limited by machine run time, I could certainly run higher loads and at
> times I do.

What is the overall throughput in iops and MB/s, on both baremetal and virt?

Paolo