From: Andrea Vai <andrea.vai@unipv.it>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg KH <gregkh@linuxfoundation.org>, linux-usb@vger.kernel.org
Subject: Re: Slow I/O on USB media
Date: Mon, 01 Jul 2019 19:52:22 +0200 [thread overview]
Message-ID: <3e7662d1391346dd11a903e66e7a8936ca83dba9.camel@unipv.it> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1906171259500.1738-100000@iolanthe.rowland.org>
Il giorno lun, 17/06/2019 alle 13.28 -0400, Alan Stern ha scritto:
> On Mon, 17 Jun 2019, Andrea Vai wrote:
>
> > Il giorno lun, 17/06/2019 alle 12.14 -0400, Alan Stern ha scritto:
> > > On Mon, 17 Jun 2019, Andrea Vai wrote:
> > >
> > > > [...]
> > > >
> > > > That happened ALL times, so I never encountered a kernel that
> made
> > > me
> > > > say "git bisect good".
> > >
> > > Really? That strongly suggests that the 4.20 kernel also should
> > > have
> > > been marked bad. Did you really test it exactly the same way as
> all
> > > the others? That is, did you go through the entire procedure
> > > starting
> > > with "git checkout v4.20", then running the build script, then
> the
> > > reboot and "uname -a", and then the test script?
> >
> > well, honestly, no, because (sigh) I didn't know the "git
> checkout"
> > command, sorry. I started with building 4.20 from the source
> > downloaded with
> >
> > wget
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/snapshot/linux-4.20.tar.gz
> >
> > , then said "git bisect good v4.20".
> >
> > Is this different from "git checkout v4.20"? I hope it is, so we
> have
> > found the mistake I have done.
>
> In theory the results should be exactly the same. But it doesn't
> hurt
> to check.
>
> > > Compare the mainstream 4.20 kernel with the Fedora 4.20.13
> kernel.
> > > Also, maybe compare the mainstream 4.20.13 with Fedora's
> 4.20.13.
> >
> > Sorry, what do you mean here by "compare"? And what is the
> > "mainstream"? If the mainstream is the one I got with wget, and if
> > "compare" means "see if they behave differently", so I have
> already
> > done it and they are both "good".
>
> I was trying to point out that there may be a significant difference
> between 4.20 and 4.20.13. But if you say 4.20 behaves well, this
> doesn't matter.
>
> At any rate, you are some commits you could try (beginning with
> "git
> checkout <commit>" and then running your scripts):
>
> c76cd634eb5b
> b1669432b355
> 507413a5f88a
> a52fb43a5faa
> 38fabca18fc4
> fc2fd5f0f1aa
>
> These are all between 4.20 and 5.0-rc1.
Hi,
these were all "good".
Then I ran another bisect (the sixth (!), more carefully, starting
from
git bisect good c76cd634eb5b
git bisect bad 241e39004581
), and it seems to give some consistent result.
I found that:
f664a3cc17b7d0a2bc3b3ab96181e1029b0ec0e6 is the first bad commit
commit f664a3cc17b7d0a2bc3b3ab96181e1029b0ec0e6
Author: Jens Axboe <axboe@kernel.dk>
Date: Thu Nov 1 16:36:27 2018 -0600
scsi: kill off the legacy IO path
This removes the legacy (non-mq) IO path for SCSI.
Cc: linux-scsi@vger.kernel.org
Acked-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
:040000 040000 312373927bae1c6fd1da40ded2c12dfa5e4de71c 4eccbd2c84bf83cb2eb72a81514d59ebf12866b7 M Documentation
:040000 040000 98de24b4fe20b82095f53f56c9193c5537d70ed0 8e2092780100205ae1c3723a598a89794a50677f M drivers
:040000 040000 fbc10c84d3eb6b7933598018319f96767ee3a0f3 2523940c2819e8adb32758f5093e477da481ca65 M include
I reverted it and the test succeeded.
Then I made a double check: "git clone" again; git checkout
3a7ea2c483a53fc89e336f69c6ee1d7defe00811 (the last good), and the test
succeded. Then git checkout f664a3cc17b7d0a2bc3b3ab96181e1029b0ec0e6
(the first bad) and the test failed; then reverted it and the test
succeded again.
Does it make sense?
Thanks,
Andrea
next prev parent reply other threads:[~2019-07-01 17:52 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 13:18 Slow I/O on USB media Andrea Vai
2019-05-30 13:25 ` Greg KH
2019-06-03 11:13 ` Andrea Vai
2019-06-04 5:43 ` Greg KH
2019-06-04 7:26 ` Andrea Vai
2019-06-05 7:36 ` Andrea Vai
2019-06-05 14:26 ` Alan Stern
2019-06-05 15:46 ` Andrea Vai
2019-06-05 16:11 ` Alan Stern
2019-06-05 14:55 ` Greg KH
[not found] ` <0c2adde7154b0a6c8b2ad7fc5258916731b78775.camel@unipv.it>
2019-06-05 16:23 ` Andrea Vai
2019-06-05 17:39 ` Greg KH
2019-06-06 8:41 ` Andrea Vai
2019-06-06 9:03 ` Andrea Vai
2019-06-06 14:00 ` Andrea Vai
2019-06-06 14:30 ` Alan Stern
2019-06-06 14:47 ` Greg KH
2019-06-07 7:59 ` Andrea Vai
2019-06-08 7:43 ` Andrea Vai
2019-06-08 9:29 ` Andrea Vai
2019-06-10 14:38 ` Greg KH
2019-06-11 6:48 ` Andrea Vai
2019-06-10 14:40 ` Alan Stern
2019-06-10 14:55 ` Andrea Vai
2019-06-10 16:20 ` Alan Stern
2019-06-17 15:52 ` Andrea Vai
2019-06-17 16:14 ` Alan Stern
2019-06-17 16:34 ` Andrea Vai
2019-06-17 17:28 ` Alan Stern
2019-07-01 17:52 ` Andrea Vai [this message]
2019-07-01 18:57 ` Alan Stern
2019-06-10 14:37 ` Greg KH
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