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* [PATCH 00/16] Adaptive read-ahead V7
@ 2005-11-09 13:49 Wu Fengguang
  2005-11-09 13:49 ` [PATCH 01/16] mm: delayed page activation Wu Fengguang
                   ` (16 more replies)
  0 siblings, 17 replies; 41+ messages in thread
From: Wu Fengguang @ 2005-11-09 13:49 UTC (permalink / raw)
  To: linux-kernel; +Cc: Andrew Morton

This is the 7th version of adaptive read-ahead patch.

There are various code cleanups and polish ups:
- new tunable parameters: readahead_hit_rate/readahead_live_chunk
- support sparse sequential accesses
- delay look-ahead in laptop mode
- disable look-ahead for loopback file
- make mandatory thrashing protection more simple and robust
- attempt to improve responsiveness on large I/O request size

Support for sparse reads is disabled by default. One must increase
/proc/sys/vm/readahead_hit_rate to explicitly enable it. Please
refer to Documentation/sysctl/vm.txt for details.

Currently the linux kernel does not support inter-file read-ahead.
Tero Grundstr?m takes an intresting approach that achieves it: pack
a dir of small files into a loopback file with reiserfs filesystem, and
turn on sparse read support. But be prepared to waste some memory by
this way :(

For crazy laptop users who prefer aggressive read-ahead, here is the way:

# echo 10000 > /proc/sys/vm/readahead_ratio
# blockdev --setra 524280 /dev/hda      # this is the max possible value

Notes:
- It is still an untested feature.
- It is safer to use blockdev+fadvise to increase ra-max for a single file,
  which needs patching your movie player.
- Be sure to restore them to sane values in normal operations!

Regards,
Wu

^ permalink raw reply	[flat|nested] 41+ messages in thread

end of thread, other threads:[~2005-11-20 12:53 UTC | newest]

Thread overview: 41+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-11-09 13:49 [PATCH 00/16] Adaptive read-ahead V7 Wu Fengguang
2005-11-09 13:49 ` [PATCH 01/16] mm: delayed page activation Wu Fengguang
2005-11-10  0:21   ` Nick Piggin
2005-11-10  3:15     ` Wu Fengguang
2005-11-10  9:17   ` Peter Zijlstra
2005-11-10 10:30     ` Wu Fengguang
2005-11-09 13:49 ` [PATCH 02/16] mm: balance page aging between zones Wu Fengguang
2005-11-09 13:49 ` [PATCH 03/16] radixtree: sync with mainline Wu Fengguang
2005-11-09 13:49 ` [PATCH 04/16] radix-tree: look-aside cache Wu Fengguang
2005-11-09 23:31   ` Nick Piggin
2005-11-10  5:25     ` Wu Fengguang
2005-11-10  6:50       ` Nick Piggin
2005-11-10  8:30         ` Wu Fengguang
2005-11-18 11:25         ` Wu Fengguang
2005-11-18 12:12           ` Wu Fengguang
2005-11-09 13:49 ` [PATCH 05/16] readahead: some preparation Wu Fengguang
2005-11-18  7:46   ` 2.6.15-rc1-mm2 Andrew Morton
2005-11-18  8:56     ` 2.6.15-rc1-mm2 Benoit Boissinot
2005-11-18  9:04       ` 2.6.15-rc1-mm2 Andrew Morton
2005-11-18  9:13         ` 2.6.15-rc1-mm2 Benoit Boissinot
2005-11-18 13:43         ` 2.6.15-rc1-mm2 Rafael J. Wysocki
2005-11-18 10:10     ` 2.6.15-rc1-mm2 Mauro Carvalho Chehab
2005-11-18 10:55     ` 2.6.15-rc1-mm2 Wu Fengguang
2005-11-18 11:29     ` 2.6.15-rc1-mm2 Andy Whitcroft
2005-11-18 16:29     ` 2.6.15-rc1-mm2 Michael Krufky
2005-11-20  0:23     ` 2.6.15-rc1-mm2 Michal Piotrowski
2005-11-20  8:04       ` 2.6.15-rc1-mm2 Hugh Dickins
2005-11-20 12:53         ` 2.6.15-rc1-mm2 Michal Piotrowski
2005-11-09 13:49 ` [PATCH 06/16] readahead: call scheme Wu Fengguang
2005-11-09 13:49 ` [PATCH 07/16] readahead: tunable parameters Wu Fengguang
2005-11-09 13:49 ` [PATCH 08/16] readahead: state based method Wu Fengguang
2005-11-09 13:49 ` [PATCH 09/16] readahead: context " Wu Fengguang
2005-11-09 13:49 ` [PATCH 10/16] readahead: other methods Wu Fengguang
2005-11-09 13:49 ` [PATCH 11/16] readahead: mandatory thrashing protection Wu Fengguang
2005-11-09 13:49 ` [PATCH 12/16] readahead: events accounting Wu Fengguang
2005-11-09 13:49 ` [PATCH 13/16] readahead: page aging accounting Wu Fengguang
2005-11-09 13:49 ` [PATCH 14/16] readahead: laptop mode support Wu Fengguang
2005-11-09 13:49 ` [PATCH 15/16] readahead: disable look-ahead for loopback file Wu Fengguang
2005-11-09 13:49 ` [PATCH 16/16] io: reduce lantency Wu Fengguang
2005-11-09 20:39 ` [PATCH 00/16] Adaptive read-ahead V7 Christoph Lameter
2005-11-10 10:19   ` Wu Fengguang

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