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etc:users:research:io-scheduler [2015/08/25 08:22] 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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 == io scheduler == == io scheduler ==
  
-{{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.1440480150.txt.gz · Last modified: 2015/08/25 08:22 by kkv