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bdi write bandwidth estimation

Wu Fengguang linux-fsdevel lkml 1 version In review

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  1. v1 Latest3 patches 2 repliesIn review

Patches in v1 No applies recorded yet

#Subject and filesSizeRepliesApplied
1/3writeback: account per-bdi accumulated written pagesinclude/linux/backing-dev.h mm/backing-dev.c mm/page-writeback.c+10 -20 replies
2/3writeback: bdi write bandwidth estimationfs/fs-writeback.c include/linux/backing-dev.h include/linux/writeback.h +2 more+114 -00 replies
3/3writeback: show bdi write bandwidth in debugfsmm/backing-dev.c+13 -110 replies

Reviews trailers per patch

1 of 3 patches has a Reviewed-by or Acked-by.

PatchKOSAKI Motohiro
1/3R-b
2/3
3/3

Trailers given in replies are filled; those carried in the patches from earlier versions are outlined with dashes.

Read the v1 thread

Cover letter [PATCH 0/3] bdi write bandwidth estimation

Do bdi write bandwidth estimation in the flusher thread at 200ms intervals, and in case the flusher is blocked syncing large files, the throttled dirtier tasks will back it up.

To get an idea of the adaption speed and fluctuation range, here are some real examples (check the red dots and the yellow line):

http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v8/3G/xfs-1dd-4k-8p-2948M-20:10-3.0.0-rc2-next-20110610+-2011-06-12.21:51/balance_dirty_pages-bandwidth.png
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v8/3G/ext3-1dd-4k-8p-2948M-20:10-3.0.0-rc2-next-20110610+-2011-06-12.22:02/balance_dirty_pages-bandwidth.png
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v8/3G/ext4-1dd-4k-8p-2948M-20:10-3.0.0-rc2-next-20110610+-2011-06-12.21:57/balance_dirty_pages-bandwidth.png
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v8/3G/btrfs-1dd-4k-8p-2948M-20:10-3.0.0-rc2-next-20110610+-2011-06-12.22:07/balance_dirty_pages-bandwidth.png

The old version outputs, for your reference:

http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/4G-60%25/ext3-1dd-1M-8p-3911M-60%25-2.6.38-rc5-dt6+-2011-02-22-11-51/balance_dirty_pages-bandwidth.png
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/4G-60%25/xfs-1dd-1M-8p-3911M-60%25-2.6.38-rc5-dt6+-2011-02-22-11-10/balance_dirty_pages-bandwidth.png
http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/balance_dirty_pages-bandwidth.png

This is merely the estimation part. The in-kernel users of the estimated bandwidth will follow in the coming series.

Thanks,
Fengguang