Well in normal use user applications are the ones that put the load on
the CPU. The kernel is pretty much lightweight in size and work when non
kernel intensive tasks are at hand (like gigabit links in the networks,
etc). The good news is that the kernel will have its own core to play with.
On 08/17/2010 08:00 AM, freebsd-stable-request@freebsd.org
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> Today's Topics:
>
> 1. Re: Inconsistent IO performance (Ivan Voras)
> 2. Re: Inconsistent IO performance (Kevin Oberman)
> 3. STABLE kernel panic: privileged instruction fault (Alexey Tarasov)
> 4. Re: Inconsistent IO performance (Jeremy Chadwick)
> 5. Re: Inconsistent IO performance (Jeremy Chadwick)
> 6. Re: STABLE kernel panic: privileged instruction fault
> (Kostik Belousov)
> 7. Re: STABLE kernel panic: privileged instruction fault
> (Alexey Tarasov)
> 8. Re: STABLE kernel panic: privileged instruction fault
> (Kostik Belousov)
> 9. Re: STABLE kernel panic: privileged instruction fault
> (Alexey Tarasov)
> 10. Re: STABLE kernel panic: privileged instruction fault
> (Kostik Belousov)
> 11. Re: STABLE kernel panic: privileged instruction fault
> (Alexey Tarasov)
> 12. Re: RELENG_7 em problems (and RELENG_8) (Mike Tancsa)
> 13. Performance AMD Phenom II X6 1090T (Vladislav V. Prodan)
> 14. Crash in dummynet. (Pawel Tyll)
> 15. Re: Crash in dummynet. (Luigi Rizzo)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 16 Aug 2010 15:03:23 +0200
> From: Ivan Voras<ivoras@freebsd.org>
> Subject: Re: Inconsistent IO performance
> To:freebsd-stable@freebsd.org
> Message-ID:<i4bcuv$213$1@dough.gmane.org>
> Content-Type: text/plain; charset=UTF-8
>
> On 13.8.2010 18:01, Kevin Oberman wrote:
>> For some time I have seen very odd issues with IO performance on
>> 8-Stable. Going back to November of last year when 8.0 was released, I
>> see variations of up to 22% in identical operations. This is not a
>> degradation as the performance moves up and down.
> In 8.0-8.1 span of time there was some work on the ata driver to make it
> use MAXPHYS (128 KiB) transfer sizes instead of 64 KiB. Modifying this
> will involve changing and recompiling the kernel but if you want to try
> something and the hardware is SATA you might try the new AHCI driver
> ("ada").
>
> http://ivoras.net/blog/tree/2009-11-17.trying-ahci-in-8.0.html
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 16 Aug 2010 07:46:38 -0700
> From: "Kevin Oberman"<oberman@es.net>
> Subject: Re: Inconsistent IO performance
> To: Ivan Voras<ivoras@freebsd.org>
> Cc:freebsd-stable@freebsd.org
> Message-ID:<20100816144638.4ACF81CC3A@ptavv.es.net>
>
>> From: Ivan Voras<ivoras@freebsd.org>
>> Date: Mon, 16 Aug 2010 15:03:23 +0200
>> Sender:owner-freebsd-stable@freebsd.org
>>
>> On 13.8.2010 18:01, Kevin Oberman wrote:
>>> For some time I have seen very odd issues with IO performance on
>>> 8-Stable. Going back to November of last year when 8.0 was
released, I
>>> see variations of up to 22% in identical operations. This is not a
>>> degradation as the performance moves up and down.
>> In 8.0-8.1 span of time there was some work on the ata driver to make
it
>> use MAXPHYS (128 KiB) transfer sizes instead of 64 KiB. Modifying this
>> will involve changing and recompiling the kernel but if you want to try
>> something and the hardware is SATA you might try the new AHCI driver
>> ("ada").
>>
>> http://ivoras.net/blog/tree/2009-11-17.trying-ahci-in-8.0.html
> Thanks. I appreciate the suggestion. I am running a 8-Stable kernel
> from August 9, so I think I should be OK on this. IS there a requirement
> to set some parameter in the kernel config to take advantage of this?
>
> While the ThinkPad has a SATA ICH6-M chip-set, it does not provide or any
> SATA connections. Both SATA ports a run to a SATA/PATA converter chip
> and the only 2 physical connections available are PATA. I am assuming
> that this is because 2.5 in. SATA drives were pretty much unavailable
> when this system was shipped. This was the last of the T43 series and
> was dropped from the product line by Lenovo about a month after I got
> it, to be replaced by T60 systems running Core2 chips and using SATA
> drives.
>
> Just lousy timing almost 4 years ago.
>
> Thanks again!