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Re: [Virtio-fs] [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no t
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Virtio-fs] [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no thread pool |
Date: |
Mon, 9 Nov 2020 10:02:18 +0000 |
User-agent: |
Mutt/1.14.6 (2020-07-11) |
* Vivek Goyal (vgoyal@redhat.com) wrote:
> On Fri, Nov 06, 2020 at 08:33:50PM +0000, Venegas Munoz, Jose Carlos wrote:
> > Hi Vivek,
> >
> > I have tested with Kata 1.12-apha0, the results seems that are better for
> > the use fio config I am tracking.
> >
> > The fio config does randrw:
> >
> > fio --direct=1 --gtod_reduce=1 --name=test --filename=random_read_write.fio
> > --bs=4k --iodepth=64 --size=200M --readwrite=randrw --rwmixread=75
> >
>
> Hi Carlos,
>
> Thanks for the testing.
>
> So basically two conclusions from your tests.
>
> - for virtiofs, --thread-pool-size=0 is performing better as comapred
> to --thread-pool-size=1 as well as --thread-pool-size=64. Approximately
> 35-40% better.
>
> - virtio-9p is still approximately 30% better than virtiofs
> --thread-pool-size=0.
>
> As I had done the analysis that this particular workload (mixed read and
> write) is bad with virtiofs because after every write we are invalidating
> attrs and cache so next read ends up fetching attrs again. I had posted
> patches to gain some of the performance.
>
> https://lore.kernel.org/linux-fsdevel/20200929185015.GG220516@redhat.com/
>
> But I got the feedback to look into implementing file leases instead.
>
> Anyway, good to know that --thread-pool-size=0 narrows the performance
> gap substantially (more than half) for this workload. I will look into
> identifying further bottlenecks.
Could you try this thread-pool-size=0 together with your attr patches;
does that catch up to 9p (even though I know you need to rework the attr
stuff as leases).
> Given in my tests, most of the workload benefited from
> --thread-pool-size=0, may be this can be the default and user can
> opt-in for a thread pool (--thread-pool-size=64) once it is known
> that a particular workload benefits from it.
>
> David, Stefan, WDYT?
I think having the option makes sense; the default I'm not sure about;
what confuses me is why it helps - although it's also interesting it
helps 9p as well.
Dave
>
> Thanks
> Vivek
>
> > - I can see better results with this patch
> > - 9pfs is still better in the case of Kata because of the use of:
> > https://github.com/kata-containers/packaging/blob/stable-1.12/qemu/patches/5.0.x/0001-9p-removing-coroutines-of-9p-to-increase-the-I-O-per.patch
> >
> > Results:
> > ./fio-results-run_virtiofs_tread_pool_0
> > READ: bw=42.8MiB/s (44.8MB/s), 42.8MiB/s-42.8MiB/s (44.8MB/s-44.8MB/s),
> > io=150MiB (157MB), run=3507-3507msec
> > WRITE: bw=14.3MiB/s (14.9MB/s), 14.3MiB/s-14.3MiB/s (14.9MB/s-14.9MB/s),
> > io=49.0MiB (52.4MB), run=3507-3507msec
> > ./fio-results-run_9pfs
> > READ: bw=55.1MiB/s (57.8MB/s), 55.1MiB/s-55.1MiB/s (57.8MB/s-57.8MB/s),
> > io=150MiB (157MB), run=2722-2722msec
> > WRITE: bw=18.4MiB/s (19.3MB/s), 18.4MiB/s-18.4MiB/s (19.3MB/s-19.3MB/s),
> > io=49.0MiB (52.4MB), run=2722-2722msec
> > ./fio-results-run_virtiofs_tread_pool_1
> > READ: bw=34.5MiB/s (36.1MB/s), 34.5MiB/s-34.5MiB/s (36.1MB/s-36.1MB/s),
> > io=150MiB (157MB), run=4354-4354msec
> > WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s),
> > io=49.0MiB (52.4MB), run=4354-4354msec
> > ./fio-results-run_virtiofs_tread_pool_64
> > READ: bw=32.3MiB/s (33.8MB/s), 32.3MiB/s-32.3MiB/s (33.8MB/s-33.8MB/s),
> > io=150MiB (157MB), run=4648-4648msec
> > WRITE: bw=10.8MiB/s (11.3MB/s), 10.8MiB/s-10.8MiB/s (11.3MB/s-11.3MB/s),
> > io=49.0MiB (52.4MB), run=4648-4648msec
> >
> > Next:
> > - run https://github.com/rhvgoyal/virtiofs-tests for tread_pool_0,
> > tread_pool_64, and 9pfs
> > - Test
> > https://lore.kernel.org/linux-fsdevel/20201009181512.65496-1-vgoyal@redhat.com/
> >
> > All the testing for kata is based in:
> > https://github.com/jcvenegas/mrunner/blob/master/scripts/bash_workloads/build-qemu-and-run-fio-test.sh
> >
> > I ran this using an azure VM.
> >
> > Cheers,
> > Carlos
> >
> >
> > On 05/11/20 13:53, "Vivek Goyal" <vgoyal@redhat.com> wrote:
> >
> > On Thu, Nov 05, 2020 at 02:44:16PM -0500, Vivek Goyal wrote:
> > > Right now we create a thread pool and main thread hands over the
> > request
> > > to thread in thread pool to process. Number of threads in thread pool
> > > can be managed by option --thread-pool-size.
> > >
> > > There is a chance that in case of some workloads, we might get better
> > > performance if we don't handover the request to a different thread
> > > and process in the context of thread receiving the request.
> > >
> > > To implement that, redefine the meaning of --thread-pool-size=0 to
> > > mean that don't use a thread pool. Instead process the request in
> > > the context of thread receiving request from the queue.
> > >
> > > I can't think how --thread-pool-size=0 is useful and hence using
> > > that. If it is already useful somehow, I could look at defining
> > > a new option say "--no-thread-pool".
> > >
> > > I think this patch will be used more as a debug help to do comparison
> > > when it is more effecient to do not hand over the requests to a
> > > thread pool.
> >
> > I ran virtiofs-tests to comapre --thread-pool-size=0 and
> > --thread-pool-size=64. And results seem to be all over the place. In
> > some cases thread pool seems to perform batter and in other cases
> > no-thread-pool seems to perform better.
> >
> > But in general it looks like that except for the case of libaio
> > workload,
> > no-thread-pool is helping.
> >
> > Thanks
> > Vivek
> >
> > NAME WORKLOAD Bandwidth IOPS
> >
> > thread-pool seqread-psync 682.4mb 170.6k
> >
> > no-thread-pool seqread-psync 679.3mb 169.8k
> >
> >
> > thread-pool seqread-psync-multi 2415.9mb 603.9k
> >
> > no-thread-pool seqread-psync-multi 2528.5mb 632.1k
> >
> >
> > thread-pool seqread-mmap 591.7mb 147.9k
> >
> > no-thread-pool seqread-mmap 595.6mb 148.9k
> >
> >
> > thread-pool seqread-mmap-multi 2195.3mb 548.8k
> >
> > no-thread-pool seqread-mmap-multi 2286.1mb 571.5k
> >
> >
> > thread-pool seqread-libaio 329.1mb 82.2k
> >
> > no-thread-pool seqread-libaio 271.5mb 67.8k
> >
> >
> > thread-pool seqread-libaio-multi 1387.1mb 346.7k
> >
> > no-thread-pool seqread-libaio-multi 1508.2mb 377.0k
> >
> >
> > thread-pool randread-psync 59.0mb 14.7k
> >
> > no-thread-pool randread-psync 78.5mb 19.6k
> >
> >
> > thread-pool randread-psync-multi 226.4mb 56.6k
> >
> > no-thread-pool randread-psync-multi 289.2mb 72.3k
> >
> >
> > thread-pool randread-mmap 48.4mb 12.1k
> >
> > no-thread-pool randread-mmap 57.4mb 14.3k
> >
> >
> > thread-pool randread-mmap-multi 183.5mb 45.8k
> >
> > no-thread-pool randread-mmap-multi 240.5mb 60.1k
> >
> >
> > thread-pool randread-libaio 329.4mb 82.3k
> >
> > no-thread-pool randread-libaio 261.8mb 65.4k
> >
> >
> > thread-pool randread-libaio-multi 252.1mb 63.0k
> >
> > no-thread-pool randread-libaio-multi 278.3mb 69.5k
> >
> >
> > thread-pool seqwrite-psync 54.9mb 13.7k
> >
> > no-thread-pool seqwrite-psync 77.8mb 19.4k
> >
> >
> > thread-pool seqwrite-psync-multi 219.9mb 54.9k
> >
> > no-thread-pool seqwrite-psync-multi 314.8mb 78.7k
> >
> >
> > thread-pool seqwrite-mmap 191.7mb 47.9k
> >
> > no-thread-pool seqwrite-mmap 201.4mb 50.3k
> >
> >
> > thread-pool seqwrite-mmap-multi 346.6mb 86.6k
> >
> > no-thread-pool seqwrite-mmap-multi 387.6mb 96.9k
> >
> >
> > thread-pool seqwrite-libaio 306.4mb 76.6k
> >
> > no-thread-pool seqwrite-libaio 248.2mb 62.0k
> >
> >
> > thread-pool seqwrite-libaio-multi 328.5mb 82.1k
> >
> > no-thread-pool seqwrite-libaio-multi 305.6mb 76.4k
> >
> >
> > thread-pool randwrite-psync 55.6mb 13.9k
> >
> > no-thread-pool randwrite-psync 81.2mb 20.3k
> >
> >
> > thread-pool randwrite-psync-multi 227.0mb 56.7k
> >
> > no-thread-pool randwrite-psync-multi 311.6mb 77.8k
> >
> >
> > thread-pool randwrite-mmap 35.3mb 9038
> >
> > no-thread-pool randwrite-mmap 58.1mb 14.5k
> >
> >
> > thread-pool randwrite-mmap-multi 140.8mb 35.2k
> >
> > no-thread-pool randwrite-mmap-multi 210.5mb 52.6k
> >
> >
> > thread-pool randwrite-libaio 307.1mb 76.7k
> >
> > no-thread-pool randwrite-libaio 279.4mb 69.8k
> >
> >
> > thread-pool randwrite-libaio-multi 361.3mb 90.3k
> >
> > no-thread-pool randwrite-libaio-multi 302.6mb 75.6k
> >
> >
> > thread-pool randrw-psync 34.1mb/11.4mb
> > 8754/2929
> > no-thread-pool randrw-psync 38.7mb/12.9mb
> > 9919/3321
> >
> > thread-pool randrw-psync-multi 126.2mb/42.3mb
> > 31.5k/10.5k
> > no-thread-pool randrw-psync-multi 172.2mb/57.7mb
> > 43.0k/14.4k
> >
> > thread-pool randrw-mmap 24.1mb/8270kb
> > 6194/2067
> > no-thread-pool randrw-mmap 42.0mb/14.0mb
> > 10.5k/3606
> >
> > thread-pool randrw-mmap-multi 127.9mb/42.8mb
> > 31.9k/10.7k
> > no-thread-pool randrw-mmap-multi 179.4mb/60.0mb
> > 44.8k/15.0k
> >
> > thread-pool randrw-libaio 64.0mb/21.4mb
> > 16.0k/5485
> > no-thread-pool randrw-libaio 79.6mb/26.6mb
> > 19.9k/6831
> >
> > thread-pool randrw-libaio-multi 174.2mb/58.3mb
> > 43.5k/14.5k
> > no-thread-pool randrw-libaio-multi 201.6mb/67.5mb
> > 50.4k/16.8k
> >
> >
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
- [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no thread pool, Vivek Goyal, 2020/11/05
- Re: [Virtio-fs] [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no thread pool, Venegas Munoz, Jose Carlos, 2020/11/17
- Re: [Virtio-fs] [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no thread pool, Christian Schoenebeck, 2020/11/17
- Re: [Virtio-fs] [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no thread pool, Vivek Goyal, 2020/11/17
- Re: [Virtio-fs] [PATCH] virtiofsd: Use --thread-pool-size=0 to mean no thread pool, Venegas Munoz, Jose Carlos, 2020/11/23