svn commit: r48686 - head/en_US.ISO8859-1/htdocs/news/status
Warren Block
wblock at FreeBSD.org
Wed Apr 20 14:26:48 UTC 2016
Author: wblock
Date: Wed Apr 20 14:26:46 2016
New Revision: 48686
URL: https://svnweb.freebsd.org/changeset/doc/48686
Log:
Whitespace-only fixes, translators please ignore.
Modified:
head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml
Modified: head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml
==============================================================================
--- head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml Wed Apr 20 14:23:55 2016 (r48685)
+++ head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml Wed Apr 20 14:26:46 2016 (r48686)
@@ -2550,38 +2550,39 @@
By default, this scheduler implements the old behavior.
In addition, an advanced adaptive scheduler is available.
Along with the scheduler, SATA disks can now use Queued Trims
- with devices that support them. Details about the new
+ with devices that support them. Details about the new
scheduler are available in the
<a href="https://people.freebsd.org/~imp/bsdcan2015/iosched-v3.pdf">I/O Scheduling in FreeBSD's CAM Subsystem article (PDF)</a>
or from
<a href="https://www.youtube.com/watch?v=3WqOLolj5EU">the BSDCan 2015 talk</a>.</p>
- <p>The adaptive I/O scheduler is disabled by default, but can be enabled
- with options CAM_ADAPTIVE_IOSCHED in the kernel config file. This
- scheduler allows favoring reads over writes (or vice versa), controlling
- the IOPs, bandwidth, or concurrent operations (read, write, trim), and
- permits the selection of static or dynamic control of these operations. In
- addition, a number of statistics are collected for drive operations
- that are published via sysctl. One advanced use for the adaptive I/O
- scheduler is to compensate for deficiencies in some consumer-grade
- SSDs. These SSDs exhibit a performance cliff if too much data is written
- to them too quickly due to internal garbage collection. Without the
- I/O scheduler, read and write performance drop substantially once
- garbage collection kicks in. The adaptive I/O scheduler can be
- configured to monitor read latency. As read latency climbs, the I/O
- scheduler reduces the allowed write throughput, within limits, to
- attempt to maximize read performance. A simple use of the adaptive I/O
- scheduler would be to limit write bandwidth, IOPs or concurrent
- operations statically.</p>
+ <p>The adaptive I/O scheduler is disabled by default, but can be
+ enabled with options CAM_ADAPTIVE_IOSCHED in the kernel config
+ file. This scheduler allows favoring reads over writes (or
+ vice versa), controlling the IOPs, bandwidth, or concurrent
+ operations (read, write, trim), and permits the selection of
+ static or dynamic control of these operations. In addition, a
+ number of statistics are collected for drive operations that
+ are published via sysctl. One advanced use for the adaptive
+ I/O scheduler is to compensate for deficiencies in some
+ consumer-grade SSDs. These SSDs exhibit a performance cliff
+ if too much data is written to them too quickly due to
+ internal garbage collection. Without the I/O scheduler, read
+ and write performance drop substantially once garbage
+ collection kicks in. The adaptive I/O scheduler can be
+ configured to monitor read latency. As read latency climbs,
+ the I/O scheduler reduces the allowed write throughput, within
+ limits, to attempt to maximize read performance. A simple use
+ of the adaptive I/O scheduler would be to limit write
+ bandwidth, IOPs or concurrent operations statically.</p>
<p>Future work on the I/O scheduler will be coupled with
- improvements to the upper layers. The upper layers will be
- enhanced to communicate how urgent I/O requests are. The I/O
- scheduler will inform the upper layers of how full the I/O queues are,
- so less urgent I/O can be submitted to the lower
- layers as quickly as possible without overwhelming the lower
- layers or starving other devices of requests.</p>
-
+ improvements to the upper layers. The upper layers will be
+ enhanced to communicate how urgent I/O requests are. The I/O
+ scheduler will inform the upper layers of how full the I/O
+ queues are, so less urgent I/O can be submitted to the lower
+ layers as quickly as possible without overwhelming the lower
+ layers or starving other devices of requests.</p>
</body>
<sponsor>Netflix</sponsor>
More information about the svn-doc-head
mailing list