Date: Mon, 22 Mar 2021 08:19:40 -0700 From: Adrian Chadd <adrian.chadd@gmail.com> To: Kevin Oberman <rkoberman@gmail.com> Cc: Mark Millard <marklmi@yahoo.com>, FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org>, Konstantin Belousov <kib@freebsd.org> Subject: Re: Filesystem operations slower in 13.0 than 12.2 Message-ID: <CAJ-Vmo=sHn7X5kejcE-eYeQDKKe1=mrruZp4nQJeghdmzBEpeg@mail.gmail.com> In-Reply-To: <CAN6yY1tJXGCUK%2BCOoDO_9vGVcseogD%2BCrsdpMH9r=hvDVD3uiQ@mail.gmail.com> References: <12705C29-53EA-4484-8291-C409AF4B3DE5.ref@yahoo.com> <12705C29-53EA-4484-8291-C409AF4B3DE5@yahoo.com> <CAN6yY1tT%2Bjoi=eyqmSPYS3apSy3-6WVM13z%2BifEzCzqqHY6oLA@mail.gmail.com> <CANCZdfpkXNUcDyLHXufM3qAVbaBV7RW8Oh6bHCQzv3%2BrafHssg@mail.gmail.com> <CAN6yY1sd-7CzGczu_HK2Q8WbUoDOfGSS2%2Bb-Sr08EBMuke=3Bw@mail.gmail.com> <CANCZdfqYb8VdNbk1tdXQPpJGEaMCmGsuFcj7BR5Q3FiOd7Osag@mail.gmail.com> <CAN6yY1uc4CEv66h=rqaOne0saPEBPFaOkWWq9s5qMNu4SMzA8A@mail.gmail.com> <CAN6yY1uu=sAKFSYHW1gcKFxE3yD7-1JgL0N5j1iQsAViQ80g1w@mail.gmail.com> <F94A457A-D179-4BA7-A8A6-82609777EBFA@yahoo.com> <CAN6yY1tJXGCUK%2BCOoDO_9vGVcseogD%2BCrsdpMH9r=hvDVD3uiQ@mail.gmail.com>
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On Mon, 15 Mar 2021 at 14:58, Kevin Oberman <rkoberman@gmail.com> wrote: > > > > It appears that the messages are associated with reading > > the disk(s), not directly with writing them, where the > > reads take more than "hz * 20" time units to complete. > > (I'm looking at main (14) code.) What might contribute > > to the time taken for the pending read(s)? > > > The reference to hz * 20 woke up a few sleeping memory cells. I forgot that > I cleaned up my loader.conf. It was largely a copy of the one on my > decade-old T520. I commented out "kern.hz=100". I don't recall the details, > but I think it was actually from an even older system, my T42 from before I > retired. > > In any case, restoring this setting has greatly improved the situation. I > now have really bad disk I/O performance on large disk to disk activity > (untarring the firefox distro) instead of terrible performance and the > system freezes have vanished, though I do see pauses in response to clicks > or text entry, but the display remains active and the pauses are short... 1 > to 15 seconds, I'd guess. No, I have no idea what this indicates. ... which drive controller is this? Is it just a laptop ATA disk? > I'm still not seeing the performance I was seeing back in February when 40 > MB/s for extended intervals was common and I once untarred firefox.tar.gz2 > in under a minute and performance seldom dropped below 1.4 MB/s. Did you find a resolution? I wonder if setting kern.hz is kicking some process(es) to get some time more frequently due to bugs elsewhere in the system (interrupts, IPI handling, wake-ups, etc) -adrian
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