Date: Tue, 5 Oct 2021 14:00:54 -0600 From: Alan Somers <asomers@freebsd.org> To: Alexander Motin <mav@freebsd.org> Cc: src-committers <src-committers@freebsd.org>, "<dev-commits-src-all@freebsd.org>" <dev-commits-src-all@freebsd.org>, dev-commits-src-main@freebsd.org Subject: Re: git: 730ea72c706e - main - cam(4): Limit search for disks in SES enclosure by single bus Message-ID: <CAOtMX2i=fA4zKuW-evP8XAS_w4tCcefdA-SBWmpbLmFMKf9ZEA@mail.gmail.com> In-Reply-To: <99fe068a-356c-7d58-8c70-6ecdf504ab25@FreeBSD.org> References: <202110051904.195J48iO062191@gitrepo.freebsd.org> <CAOtMX2g5sMjFWwbJoLtxQrV3ZyBbfHCK5e5WSfeEffufwxd_3g@mail.gmail.com> <d5d8897f-5aaf-5cba-9c87-5a6977c1208e@FreeBSD.org> <CAOtMX2hqh14BaFMgdmHz-Du4LfEUufWGcV7vSBOw8=%2BJ9N3RPg@mail.gmail.com> <99fe068a-356c-7d58-8c70-6ecdf504ab25@FreeBSD.org>
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On Tue, Oct 5, 2021 at 1:55 PM Alexander Motin <mav@freebsd.org> wrote: > > On 05.10.2021 15:48, Alan Somers wrote: > > On Tue, Oct 5, 2021 at 1:41 PM Alexander Motin <mav@freebsd.org> wrote: > >> > >> On 05.10.2021 15:14, Alan Somers wrote: > >>> On Tue, Oct 5, 2021 at 1:04 PM Alexander Motin <mav@freebsd.org> wrote: > >>>> > >>>> The branch main has been updated by mav: > >>>> > >>>> URL: https://cgit.FreeBSD.org/src/commit/?id=730ea72c706ef8e025616772cfd86fd89ed3d42e > >>>> > >>>> commit 730ea72c706ef8e025616772cfd86fd89ed3d42e > >>>> Author: Alexander Motin <mav@FreeBSD.org> > >>>> AuthorDate: 2021-10-05 19:01:16 +0000 > >>>> Commit: Alexander Motin <mav@FreeBSD.org> > >>>> CommitDate: 2021-10-05 19:01:16 +0000 > >>>> > >>>> cam(4): Limit search for disks in SES enclosure by single bus > >>>> > >>>> At least for SAS that we only support now disks are typically > >>>> connected to the same bus as the enclosure. Limiting the search > >>>> scope makes it much faster on systems with multiple buses and > >>>> thousands of disks. > >>>> > >>>> Reviewed by: imp > >>>> MFC after: 2 weeks > >>>> Sponsored by: iXsystems, Inc. > >>>> Differential Revision: https://reviews.freebsd.org/D32305 > >>>> --- > >>>> sys/cam/scsi/scsi_enc_ses.c | 8 ++++++++ > >>>> 1 file changed, 8 insertions(+) > >>>> > >>>> diff --git a/sys/cam/scsi/scsi_enc_ses.c b/sys/cam/scsi/scsi_enc_ses.c > >>> > >>> > >>> Sounds juicy. Do you have any benchmarks? > >> > >> I don't think we've benchmarked that system with payload yet, if that is > >> what you mean, polishing usability. But I don't think there can be too > >> much interesting, since big speeds don't require so many HDDs these > >> days, but much smaller number of SSDs instead. This particular system > >> is about capacity -- ~20PiB raw on 1248 disks in one ZFS pool. :) > > > > 1248 disks? That's huge. But I'm not asking about throughput. Your > > commit message said "much faster". What operation is "much faster"? > > Enumerating disks at startup? That would be useful. > > I don't think you notice the difference on startup, too many other > things going on, but during idle it reduces periodic CPU load spikes by > enc_daemon processes by several times, proportionally to the number of > HBAs/buses. More annoyance than a real problem though. > > -- > Alexander Motin Yeah, I've noticed those occasional enc_daemon spikes. I was never sure what it was doing. Thanks for the fix! I'm looking forward to 13.1 a little bit more now.
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