Messages in this thread |  | | From | Marc-Christian Petersen <> | Subject | Re: [PATCH] ide write barriers | Date | Wed, 5 Feb 2003 20:53:14 +0100 |
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On Wednesday 05 February 2003 17:33, Jens Axboe wrote:
Hi Jens,
> Sure, I had that one already. BTW, I discovered that the default io thank you :)
> scheduler forgets to honor the cmd_flags, it's supposed to break like > the noop does (see very first hunk in very first file). Must have > removed that by mistake some time ago... This applies both to the > 2.4.21-pre4 patch posted and this one. well, I am impressed, really!
As you described in the patch:
+ * For journalled file systems, doing ordered writes on a commit + * block instead of explicitly doing wait_on_buffer (which is bad + * for performance) can be a big win. Block drivers supporting this ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I don't have benchmarks handy yet but as far as I can _feel_, this is a _MUST_ (I repeat: a _MUST_ for 2.4.21). And I am very good in feeling slowdowns for interactivity :)
I am running it for quite some hours now with 2.4.20. Well, maybe the nr_requests = 16 and read/write passovers changes in the elevator code give us more smoothness than w/o but in my theoretical mind, this should drop throughput. I also noticed, these changes aren't in your 2.4.21 patch. Can you explain why it is in 2.4.20 patch or why it isn't in 2.4.21 patch ? :)
Thanks alot.
/ME calls out for Con to do a benchmark with the 2.4.21 patch.
ciao, Marc
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