Messages in this thread | | | Date | Sun, 13 Jan 2008 10:16:07 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][PATCH] per-task I/O throttling |
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* Andrea Righi <righiandr@users.sourceforge.net> [2008-01-12 19:01:14]:
> Peter Zijlstra wrote: > > On Sat, 2008-01-12 at 16:27 +0530, Balbir Singh wrote: > >> * Peter Zijlstra <a.p.zijlstra@chello.nl> [2008-01-12 10:46:37]: > >> > >>> On Fri, 2008-01-11 at 23:57 -0500, Valdis.Kletnieks@vt.edu wrote: > >>>> On Fri, 11 Jan 2008 17:32:49 +0100, Andrea Righi said: > >>>> > >>>>> The interesting feature is that it allows to set a priority for each > >>>>> process container, but AFAIK it doesn't allow to "partition" the > >>>>> bandwidth between different containers (that would be a nice feature > >>>>> IMHO). For example it would be great to be able to define per-container > >>>>> limits, like assign 10MB/s for processes in container A, 30MB/s to > >>>>> container B, 20MB/s to container C, etc. > >>>> Has anybody considered allocating based on *seeks* rather than bytes moved, > >>>> or counting seeks as "virtual bytes" for the purposes of accounting (if the > >>>> disk can do 50mbytes/sec, and a seek takes 5millisecs, then count it as 100K > >>>> of data)? > >>> I was considering a time scheduler, you can fill your time slot with > >>> seeks or data, it might be what CFQ does, but I've never even read the > >>> code. > >>> > >> So far the definition of I/O bandwidth has been w.r.t time. Not all IO > >> devices have sectors; I'd prefer bytes over a period of time. > > > > Doing a time based one would only require knowing the (avg) delay of > > seeks, whereas doing a bytes based one would also require knowing the > > (avg) speed of the device. > > > > That is, if you're also interested in providing a latency guarantee. > > Because that'd force you to convert bytes to time again. > > So, what about considering both bytes/sec and io-operations/sec? In this > way we should be able to limit huge streams of data and seek storms (or > any mix of them). > > Regarding CFQ, AFAIK it's only possible to configure an I/O priorty for > a process, but there's no way for example to limit the bandwidth (or I/O > operations/sec) for a particular user or group. >
Limiting usage is also a very useful feature. Andrea could you please port your patches over to control groups.
-- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL
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