Messages in this thread | | | Date | Wed, 29 Aug 2007 02:22:47 -0700 (PDT) | From | Martin Knoblauch <> | Subject | Re: Understanding I/O behaviour - next try |
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--- Fengguang Wu <wfg@mail.ustc.edu.cn> wrote:
> On Wed, Aug 29, 2007 at 01:15:45AM -0700, Martin Knoblauch wrote: > > > > --- Fengguang Wu <wfg@mail.ustc.edu.cn> wrote: > > > > > You are apparently running into the sluggish kupdate-style > writeback > > > problem with large files: huge amount of dirty pages are getting > > > accumulated and flushed to the disk all at once when dirty > background > > > ratio is reached. The current -mm tree has some fixes for it, and > > > there are some more in my tree. Martin, I'll send you the patch > if > > > you'd like to try it out. > > > > > Hi Fengguang, > > > > Yeah, that pretty much describes the situation we end up. Although > > "sluggish" is much to friendly if we hit the situation :-) > > > > Yes, I am very interested to check out your patch. I saw your > > postings on LKML already and was already curious. Any chance you > have > > something agains 2.6.22-stable? I have reasons not to move to -23 > or > > -mm. > > Well, they are a dozen patches from various sources. I managed to > back-port them. It compiles and runs, however I cannot guarantee > more... >
Thanks. I understand the limited scope of the warranty :-) I will give it a spin today. > > > > Another thing I saw during my tests is that when writing to > NFS, > > > the > > > > "dirty" or "nr_dirty" numbers are always 0. Is this a > conceptual > > > thing, > > > > or a bug? > > > > > > What are the nr_unstable numbers? > > > > > > > Ahh. Yes, they go up to 80-90k pages. Comparable to the nr_dirty > > numbers for the disk case. Good to know. > > > > For NFS, the nr_writeback numbers seem surprisingly high. They > also go > > to 80-90k (pages ?). In the disk case they rarely go over 12k. > > Maybe the difference of throttling one single 'cp' and a dozen > 'nfsd'? >
No "nfsd" running on that box. It is just a client.
Cheers Martin
------------------------------------------------------ Martin Knoblauch email: k n o b i AT knobisoft DOT de www: http://www.knobisoft.de - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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