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etc:users:research:io-scheduler [2015/08/25 08:23] kkvetc:users:research:io-scheduler [2016/08/08 21:57] (current) – ↷ Links adapted because of a move operation 93.158.152.68
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 {{tag>linux io-scheduler}} {{tag>linux io-scheduler}}
 +
 +== Preliminary ==
 +
 +  * [[https://www.kernel.org/doc/htmldocs/kernel-api/API-generic-make-request.html| generic_make_request]]
 +  * [[https://www.kernel.org/doc/htmldocs/kernel-api/API-submit-bio.html|submit_bio]]
 +  * [[http://lxr.free-electrons.com/source/include/linux/blk_types.h#L46|bio]]
 +  * [[http://lxr.free-electrons.com/source/include/linux/fs.h#L448|block_device]]
 +  * [[http://lxr.free-electrons.com/source/include/linux/genhd.h#L165|gendisk]]
 +  * [[https://www.kernel.org/doc/htmldocs/kernel-api/API-blk-init-queue.html|blk_init_queue]]
 +
 +   #iostat -xmt 1
 +   #fio --runtime=300 --time_based --name=random-read --rw=randread --size=128m --directory=/opt/disk/
 +
 +
 +{{etc:users:research:iosched.png|}}
 +
 +  * gendisk->[request_queue]queue->[request_list]rq
 +  * http://lxr.free-electrons.com/source/drivers/ide/ide-gd.c#L420
 +
 +== Вопросы ==
 +
 +  * Q: может ли один элеватор обслуживать несколько дисков?
 +  * A: [[https://lwn.net/Articles/27055/ | One request queue can be shared across multiple physical drives]]
 +
 +  * Q: кто в каком порядке обрабатывает per-disk очереди?
 +
 +== Useful materials ==
 +
 +  * [[http://stackoverflow.com/questions/4141324/function-caller-in-linux-kernel|Print caller function]]
 +
 +== Links ==
 +
 +  * [[https://www.kernel.org/doc/htmldocs/kernel-api/index.html| Kernel API]]
 +  * [[https://scaryreasoner.wordpress.com/2013/09/14/the-life-of-io-in-the-linux-kernel/ | IO top-bottom]]
 +
etc/users/research/io-scheduler.1440480199.txt.gz · Last modified: 2015/08/25 08:23 by kkv