Hi Daniel, on Saturday, 2007-02-10 at 12:49:14, you wrote: > I will give short overview what i have tried so far. > > 1. Trying different I/O Scheduler ( cfq anticipatory and deadline) > 2. Enabling Low latency kernel and Preemptible kernel > 3. Setting 1000 HZ for timer frequency > 4. Tried the new kernel 2.6.19-gentoo-r6 and even the testing version > 2.6.20-gentoo with core 2 enabled in processor type
Oh, so it is a multicore CPU---sorry if you mentioned it already, I
had deleted the start of the thread already when I read Benno's advice.
In that case, try 100 Hz scheduling period as well. I've had very bad
experiences with I/O and 250 Hz or higher on a dual Xeon. My guess is
that it was a cache effect and therefore shouldn't happen on the
Core2Duo, but it might still be worth a try.
> As i am using Xfce i installed the diskperf-plugin which monitors disk
> I/O. The monitoring is divided in disk-read and disk-write.
> I recognized that every time when reading stops writing starts. So is
> this staggering of writing to disk normal as the programs have to read
> data they want to write to disk? On my previous machine i didn't
> recognize such a behaviour.
So you're reading and writing from/to the same disk? I'd expect that
behavior then, because the I/O scheduler tries to satisfy requests with
as little thrashing as possible. So if there are enough write requests
queued up it may keep the HD busy writing for a while before reading the
next chunk from somewhere else.
cheers!
Matthias
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