From: Andrea Vai <andrea.vai@unipv.it>
To: Bernd Schubert <bs_lists@aakef.fastmail.fm>
Cc: Ming Lei <ming.lei@redhat.com>,
"Schmid, Carsten" <Carsten_Schmid@mentor.com>,
Finn Thain <fthain@telegraphics.com.au>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Alan Stern <stern@rowland.harvard.edu>,
Jens Axboe <axboe@kernel.dk>,
Johannes Thumshirn <jthumshirn@suse.de>,
USB list <linux-usb@vger.kernel.org>,
SCSI development list <linux-scsi@vger.kernel.org>,
Himanshu Madhani <himanshu.madhani@cavium.com>,
Hannes Reinecke <hare@suse.com>, Omar Sandoval <osandov@fb.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Greg KH <gregkh@linuxfoundation.org>,
Hans Holmberg <Hans.Holmberg@wdc.com>,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: AW: Slow I/O on USB media after commit f664a3cc17b7d0a2bc3b3ab96181e1029b0ec0e6
Date: Mon, 2 Dec 2019 08:01:35 +0100 [thread overview]
Message-ID: <20191202070135.GA4634@brian.unipv.it> (raw)
In-Reply-To: <3c57bba1-831b-fc97-d5f7-e670f43fbbdc@aakef.fastmail.fm>
On 29/11/19 12:44:53, Bernd Schubert wrote:
> >> Trace attached. Produced by: start the trace script
> >> (with the pendrive already plugged), wait some seconds, run the test
> >> (1 trial, 1 GB), wait for the test to finish, stop the trace.
> >>
> >> The copy took 73 seconds, roughly as already seen before with the fast
> >> old kernel.
> >
> > This trace shows a good write IO order because the writeback IOs are
> > queued to block layer serially from the 'cp' task and writeback wq.
> >
> > However, writeback IO order is changed in current linus tree because
> > the IOs are queued to block layer concurrently from the 'cp' task
> > and writeback wq. It might be related with killing queue_congestion
> > by blk-mq.
>
> What about using direct-io to ensure order is guaranteed? Pity that 'cp'
> doesn't seem to have an option for it. But dd should do the trick.
> Andrea, can you replace cp with a dd command (on the slow kernel)?
>
> dd if=<path-to-src-file> of=<path-to-copy-on-flash-device> bs=1M
> oflag=direct
On the "new bad patched" kernel, this command take 68 seconds to complete (mean on 100 trials, with a narrow standard deviation), so perfectly
aligned with the cp command on the old fast good kernel.
Thanks, and bye
Andrea
next prev parent reply other threads:[~2019-12-02 7:01 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <307581a490b610c3025ee80f79a465a89d68ed19.camel@unipv.it>
2019-08-20 17:13 ` Slow I/O on USB media after commit f664a3cc17b7d0a2bc3b3ab96181e1029b0ec0e6 Alan Stern
2019-08-23 10:39 ` Andrea Vai
2019-08-23 20:42 ` Alan Stern
2019-08-26 6:09 ` Andrea Vai
2019-08-26 16:33 ` Alan Stern
2019-09-18 15:25 ` Andrea Vai
2019-09-18 16:30 ` Alan Stern
2019-09-19 7:33 ` Andrea Vai
2019-09-19 17:54 ` Alan Stern
2019-09-20 7:25 ` Andrea Vai
2019-09-20 7:44 ` Greg KH
2019-09-19 8:26 ` Damien Le Moal
2019-09-19 8:55 ` Ming Lei
2019-09-19 9:09 ` Damien Le Moal
2019-09-19 9:21 ` Ming Lei
2019-09-19 14:01 ` Alan Stern
2019-09-19 14:14 ` Damien Le Moal
2019-09-20 7:03 ` Andrea Vai
2019-09-25 19:30 ` Alan Stern
2019-09-25 19:36 ` Jens Axboe
2019-09-27 15:47 ` Andrea Vai
2019-11-04 16:00 ` Andrea Vai
2019-11-04 18:20 ` Alan Stern
2019-11-05 11:48 ` Andrea Vai
2019-11-05 18:31 ` Alan Stern
2019-11-05 23:29 ` Jens Axboe
2019-11-06 16:03 ` Alan Stern
2019-11-06 22:13 ` Damien Le Moal
2019-11-07 7:04 ` Andrea Vai
2019-11-07 7:54 ` Damien Le Moal
2019-11-07 18:59 ` Andrea Vai
2019-11-08 8:42 ` Damien Le Moal
2019-11-08 14:33 ` Jens Axboe
2019-11-11 10:46 ` Andrea Vai
2019-11-09 10:09 ` Ming Lei
2019-11-09 22:28 ` Ming Lei
2019-11-11 10:50 ` Andrea Vai
2019-11-11 11:05 ` Ming Lei
2019-11-11 11:13 ` Andrea Vai
2019-11-22 19:16 ` Andrea Vai
2019-11-23 7:28 ` Ming Lei
2019-11-23 15:44 ` Andrea Vai
2019-11-25 3:54 ` Ming Lei
2019-11-25 10:11 ` Andrea Vai
2019-11-25 10:29 ` Ming Lei
2019-11-25 14:58 ` Andrea Vai
2019-11-25 15:15 ` Ming Lei
2019-11-25 18:51 ` Andrea Vai
2019-11-26 2:32 ` Ming Lei
2019-11-26 7:46 ` Andrea Vai
2019-11-26 9:15 ` Ming Lei
2019-11-26 10:24 ` Ming Lei
2019-11-26 11:14 ` Andrea Vai
2019-11-27 2:05 ` Ming Lei
2019-11-27 9:39 ` Andrea Vai
2019-11-27 13:08 ` Ming Lei
2019-11-27 15:01 ` Andrea Vai
2019-11-27 0:21 ` Finn Thain
2019-11-27 8:14 ` AW: " Schmid, Carsten
2019-11-27 21:49 ` Finn Thain
2019-11-28 7:46 ` Andrea Vai
2019-11-28 8:12 ` AW: " Schmid, Carsten
2019-11-28 11:40 ` Andrea Vai
2019-11-28 17:39 ` Alan Stern
2019-11-28 9:17 ` Ming Lei
2019-11-28 17:34 ` Andrea Vai
2019-11-29 0:57 ` Ming Lei
2019-11-29 2:35 ` Ming Lei
2019-11-29 14:41 ` Andrea Vai
2019-12-03 2:23 ` Ming Lei
2019-12-10 7:35 ` Andrea Vai
2019-12-10 8:05 ` Ming Lei
2019-12-11 2:41 ` Theodore Y. Ts'o
2019-12-11 4:00 ` Ming Lei
2019-12-11 16:07 ` Theodore Y. Ts'o
2019-12-11 21:33 ` Ming Lei
2019-12-12 7:34 ` Andrea Vai
2019-12-18 8:25 ` Andrea Vai
2019-12-18 9:48 ` Ming Lei
[not found] ` <b1b6a0e9d690ecd9432025acd2db4ac09f834040.camel@unipv.it>
2019-12-23 13:08 ` Ming Lei
2019-12-23 14:02 ` Andrea Vai
2019-12-24 1:32 ` Ming Lei
2019-12-24 8:04 ` Andrea Vai
2019-12-24 8:47 ` Ming Lei
2019-12-23 16:26 ` Theodore Y. Ts'o
2019-12-23 16:29 ` Andrea Vai
2019-12-23 17:22 ` Theodore Y. Ts'o
2019-12-23 18:45 ` Andrea Vai
2019-12-23 19:53 ` Theodore Y. Ts'o
2019-12-24 1:27 ` Ming Lei
2019-12-24 6:49 ` Andrea Vai
2019-12-24 8:51 ` Andrea Vai
2019-12-24 9:35 ` Ming Lei
2019-12-25 5:17 ` Theodore Y. Ts'o
2019-12-26 2:27 ` Ming Lei
2019-12-26 3:30 ` Theodore Y. Ts'o
2019-12-26 8:37 ` Ming Lei
2020-01-07 7:51 ` Andrea Vai
[not found] ` <20200101074310.10904-1-hdanton@sina.com>
2020-01-01 13:53 ` slow IO on USB media Ming Lei
2019-11-29 11:44 ` AW: Slow I/O on USB media after commit f664a3cc17b7d0a2bc3b3ab96181e1029b0ec0e6 Bernd Schubert
2019-12-02 7:01 ` Andrea Vai [this message]
2019-11-28 17:10 ` Andrea Vai
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