Messages in this thread | | | From | Al Boldi <> | Subject | Re: [RFC] ext3: per-process soft-syncing data=ordered mode | Date | Mon, 28 Jan 2008 23:17:19 +0300 |
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Jan Kara wrote: > On Sat 26-01-08 08:27:59, Al Boldi wrote: > > Do you mean there is a locking problem? > > No, but if you write to an mmaped file, then we can find out only later > we have dirty data in pages and we call writepage() on behalf of e.g. > pdflush().
Ok, that's a special case, which we could code for, but doesn't seem worthwile. In any case, child-forks should inherit its parent mode.
> > > And in case of DB, they use direct-io > > > anyway most of the time so they don't care about journaling mode > > > anyway. > > > > Testing with sqlite3 and mysql4 shows that performance drastically > > improves with writeback writeout. > > And do you have the databases configured to use direct IO or not?
I don't think so, but these tests are only meant to expose the underlying problem which needs to be fixed, while this RFC proposes a useful workaround.
In another post Jan Kara wrote: > Hmm, if you're willing to test patches, then you could try a debug > patch: http://bugzilla.kernel.org/attachment.cgi?id=14574 > and send me the output. What kind of load do you observe problems with > and which problems exactly?
8M-record insert into indexed db-table: ordered writeback sqlite3: 75m22s 8m45s mysql4 : 23m35s 5m29s
Also, see the 'konqueror deadlocks in 2.6.22' thread.
Thanks!
-- Al
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