Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes

From	<tomas@tuxteam.de>
Newsgroups	linux.debian.user
Subject	Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes
Date	2024-09-16 06:40 +0200
Message-ID	<JnbGN-cCjP-1@gated-at.bofh.it> (permalink)
References	(3 earlier) <Jl4T7-bgM9-1@gated-at.bofh.it> <JmdhD-bYSL-7@gated-at.bofh.it> <JmdhD-bYSL-5@gated-at.bofh.it> <Jmjn3-c2nU-3@gated-at.bofh.it> <Jn9Yl-cAXd-1@gated-at.bofh.it>
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On Sun, Sep 15, 2024 at 10:47:46PM -0400, Michael Stone wrote:
> On Fri, Sep 13, 2024 at 08:33:55PM +0200, tomas@tuxteam.de wrote:

[rough dd test]

> It's an invalid test because you hit the end of the device; there's nothing
> left to sync.

This doesn't make sense to me. The question was whether dd writes "raw" to
the device or "buffered" (meaning that its output ends up in OS buffers to
be flushed later). Since the whole thing (dd + OS) can't look into the
future, stuff will end in buffers to be flushed if the second is the case,
regardless on whether dd "hits the end of the device" or not.

Those buffers would have to be flushed, thus showing up in sync's time.
They do not, therefore I conclude that we have the first case.

What am I missing?

Cheers
-- 
t

Thread

Disk drive zero-fill benchmarks for various synchronization methods  and block sizes David Christensen <dpchrist@holgerdanske.com> - 2024-09-08 20:10 +0200
  Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2024-09-09 11:00 +0200
    Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes David Wright <deblis@lionunicorn.co.uk> - 2024-09-09 15:40 +0200
      Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2024-09-10 11:00 +0200
        Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2024-09-13 14:10 +0200
          Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes <tomas@tuxteam.de> - 2024-09-13 20:40 +0200
            Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes Michael Stone <mstone@debian.org> - 2024-09-16 04:50 +0200
              Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes <tomas@tuxteam.de> - 2024-09-16 06:40 +0200
          Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes Jeffrey Walton <noloader@gmail.com> - 2024-09-13 21:10 +0200
            Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes David Christensen <dpchrist@holgerdanske.com> - 2024-09-14 01:40 +0200
            Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2024-09-16 11:10 +0200
              Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes <tomas@tuxteam.de> - 2024-09-16 11:20 +0200
                Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2024-09-16 12:50 +0200
                Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes <tomas@tuxteam.de> - 2024-09-16 13:00 +0200
                Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes Michael Stone <mstone@debian.org> - 2024-09-16 13:20 +0200
          Re: Disk drive zero-fill benchmarks for various synchronization methods and  block sizes "Rick Thomas" <rick.thomas@pobox.com> - 2024-09-13 23:20 +0200
          Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes David Wright <deblis@lionunicorn.co.uk> - 2024-09-16 21:20 +0200
  Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes Michael Stone <mstone@debian.org> - 2024-09-16 05:00 +0200
    Re: Disk drive zero-fill benchmarks for various synchronization methods and block sizes Anssi Saari <anssi.saari@debian-user.mail.kapsi.fi> - 2024-09-16 12:20 +0200
      Re: Disk drive zero-fill benchmarks for various synchronization  methods and block sizes Michael Stone <mstone@debian.org> - 2024-09-16 13:40 +0200

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