Re: Linux disk performance.

From: Manish Regmi
Date: Mon Dec 18 2006 - 07:39:57 EST


On 12/18/06, Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
if you want truely really smooth writes you'll have to work for it,
since "bumpy" writes tend to be better for performance so naturally the
kernel will favor those.

to get smooth writes you'll need to do a threaded setup where you do an
msync/fdatasync/sync_file_range on a frequent-but-regular interval from
a thread. Be aware that this is quite likely to give you lower maximum
performance than the batching behavior though.


Thanks...

But isn't O_DIRECT supposed to bypass buffering in Kernel?
Doesn't it directly write to disk?
I tried to put fdatasync() at regular intervals but there was no
visible effect.

--
---------------------------------------------------------------
regards
Manish Regmi

---------------------------------------------------------------
UNIX without a C Compiler is like eating Spaghetti with your mouth
sewn shut. It just doesn't make sense.
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