From: "Thomas Schmitt" <scdbackup@gmx.net>
To: linux-kernel@vger.kernel.org
Cc: jrdejong@gmail.com
Subject: Re: SCSI sr driver: parallel writes to optical serialized which hurts performance (sr_mutex)
Date: Sat, 05 Mar 2016 21:47:00 +0100 [thread overview]
Message-ID: <11777578711288137074@scdbackup.webframe.org> (raw)
In-Reply-To: <CAHrxqh3pGJzVoxtgNgmbVSdwXSiH2cLGYpU4R2+eDEEfaHxi7A@mail.gmail.com>
Hi,
as developer of libburn i got several user complaints about poor
concurrent throughput. Since last year i suffer from it myself
on kernel 3.16 of Debian 8. Before i had 2.6.18 which did very well
in that aspect.
An old workaround for IDE master-slave concurrency problems brings
a certain degree of relief on some drives. See
http://libburnia-project.org/wiki/ConcurrentLinuxSr
But the much better solution would be to remove the need for the
global lock shared by all ioctl(SG_IO) to all /dev/sr*.
Given the old reports of Otto Meta about possible race conditions
with drives at the same IDE controller, and the rareness of IDE
attached drives nowadays, i propose to keep the global sr_mutex lock
for IDE attached drives.
Question is how this can be determined from the device parameters
of the calls in question:
struct block_device *bdev
struct gendisk *disk
struct scsi_cd *cd
Have a nice day :)
Thomas
next prev parent reply other threads:[~2016-03-05 20:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-01 11:00 SCSI sr driver: parallel writes to optical serialized which hurts performance (sr_mutex) Johan de Jong
2016-03-05 20:15 ` Johan de Jong
2016-03-05 20:47 ` Thomas Schmitt [this message]
2016-03-07 12:13 ` One Thousand Gnomes
2016-03-07 13:11 ` Thomas Schmitt
2016-03-05 21:25 ` Wakko Warner
2016-03-05 21:36 ` Johan de Jong
2016-03-06 2:06 ` Wakko Warner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=11777578711288137074@scdbackup.webframe.org \
--to=scdbackup@gmx.net \
--cc=jrdejong@gmail.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox