dell precision m50 _very_ slow paging/swapping

dell precision m50 _very_ slow paging/swapping

[Roe Peterson]

Although Dell doesn't consider the precision M50 a laptop (it's a
"portable workstation"), this list
looks like a good place to start :-)

I'm having a big problem with a brand-new M50.  The symptoms persist
whether I try Redhat 7.3
or 8.0.

Generally, everything is fine, right up to the time the machine starts
paging out to disk.  Then, the
system essentially grinds to a halt.

The paging activity eventually gets done, and, once things are running
in RAM, the machine flies.

However, I've seen starting mozilla take ~45 seconds, and starting vi
take 15!!!

This machine:

    1.8Ghz Pentium 4 Pro Mobile CPU
    256MB RAM
    40 GB hard drive (userland benchmarks look good - 16-18 MB/sec
transfer rates)
    nVidia Quadro 4 GoGl video
    PIIX4 EIDE chipset
    i810 compatible sound
    Latest BIOS upgrade from Dell (A07)

I see the same result with redhat 7.3 and 8.0.

I've even disabled the PIIX support in the kernel, on the theory that
something in the IDE
subsystem was responsible - no change, except (as expected) user mode
disk IO slowed down
somewhat.

I freely admit I'm confused.

Dell support is:
    1 - extremely frustrating
    2 - totally useless

And I don't even want to talk about Redhat.

Can anyone point me at a theory, even??

Re: dell precision m50 _very_ slow paging/swapping

[Andrew Morton]

On Sat January 11 2003 07:37, Roe Peterson wrote:
>
> Although Dell doesn't consider the precision M50 a laptop (it's a
> "portable workstation"), this list
> looks like a good place to start :-)
>
> I'm having a big problem with a brand-new M50.  The symptoms persist
> whether I try Redhat 7.3
> or 8.0.
>
> Generally, everything is fine, right up to the time the machine starts
> paging out to disk.  Then, the
> system essentially grinds to a halt.
>

You'd need to determine whether the CPU is busy or idle when this is
happening.

If it's busy, profile the kernel:

- boot with "profile=1" on the kernel command line

-
	readprofile -r
	<do something>
	readprofile -v -m /boot/System.map | sort -n +2 | tail -40

It it's not busy, then:

while true
do
	ps axl | grep ' D '
	sleep 1
done &
<do something>

Re: dell precision m50 _very_ slow paging/swapping

[Andrew McGregor]

Have you tried hdparm to see if the disk is in a stupid mode and needs 
something (DMA most likely) switched on to perform?  Dell BIOSes often get 
this wrong.  idebus=66 on the kernel command line is appropriate too.

Andrew

--On Saturday, January 11, 2003 10:12:55 -0800 Andrew Morton 
<akpm@digeo.com> wrote:

> On Sat January 11 2003 07:37, Roe Peterson wrote:
>>
>> Although Dell doesn't consider the precision M50 a laptop (it's a
>> "portable workstation"), this list
>> looks like a good place to start :-)
>>
>> I'm having a big problem with a brand-new M50.  The symptoms persist
>> whether I try Redhat 7.3
>> or 8.0.
>>
>> Generally, everything is fine, right up to the time the machine starts
>> paging out to disk.  Then, the
>> system essentially grinds to a halt.
>>
>
> You'd need to determine whether the CPU is busy or idle when this is
> happening.
>
> If it's busy, profile the kernel:
>
> - boot with "profile=1" on the kernel command line
>
> -
> 	readprofile -r
> 	<do something>
> 	readprofile -v -m /boot/System.map | sort -n +2 | tail -40
>
> It it's not busy, then:
>
> while true
> do
> 	ps axl | grep ' D '
> 	sleep 1
> done &
> <do something>
>
>
>
> -
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