2.6.2-rc2 Interactivity problems with SMP + HT

2.6.2-rc2 Interactivity problems with SMP + HT

[Catalin BOIE]

Hello!

First, thank you very much for the effort you put for Linux!

I have a Intel motherboard with SATA (2 Maxtor disks).
CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
1 GB RAM.

Load: postgresql and apache. Very low load (3-4 clients).

RAID: Yes, soft RAID1 between the 2 disks.

I have times when the console freeze for 3-4 seconds!
2.6.0-test11 had the same problem (maybe longer times).
2.6.1-rc2 worked good in this respect but crashed after 2 days. :(
2.6.2-rc2 is back with the delay.

Do you know why this can happen?

Thank you very much!

---
Catalin(ux) BOIE
catab@deuroconsult.ro

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Nick Piggin]

Catalin BOIE wrote:

>Hello!
>
>First, thank you very much for the effort you put for Linux!
>
>I have a Intel motherboard with SATA (2 Maxtor disks).
>CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
>1 GB RAM.
>
>Load: postgresql and apache. Very low load (3-4 clients).
>
>RAID: Yes, soft RAID1 between the 2 disks.
>
>I have times when the console freeze for 3-4 seconds!
>2.6.0-test11 had the same problem (maybe longer times).
>2.6.1-rc2 worked good in this respect but crashed after 2 days. :(
>2.6.2-rc2 is back with the delay.
>
>Do you know why this can happen?
>
>

There haven't been many scheduler changes there recently so
maybe its something else.

But you could try the latest -mm kernels. They have some
Hyperthreading work in them (you need to enable CONFIG_SCHED_SMT).

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Catalin BOIE]

> >Do you know why this can happen?
> >
> >
>
> There haven't been many scheduler changes there recently so
> maybe its something else.
>
> But you could try the latest -mm kernels. They have some
> Hyperthreading work in them (you need to enable CONFIG_SCHED_SMT).

It's a production server and now, after the crash I'm a little worried
about side effects. I have to wait some time till I play with it again.

Thank you very much, Nick.

>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

---
Catalin(ux) BOIE
catab@deuroconsult.ro

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Robert M. Hyatt]

It might be some IDE disk I/O that results from flushing buffers or 
whatever.  I don't see this on my SCSI boxes, but I have seen an IDE 
box get sluggish at times due to I/O.

On Thu, 29 Jan 2004, Nick Piggin 
wrote:

> 
> 
> Catalin BOIE wrote:
> 
> >Hello!
> >
> >First, thank you very much for the effort you put for Linux!
> >
> >I have a Intel motherboard with SATA (2 Maxtor disks).
> >CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
> >1 GB RAM.
> >
> >Load: postgresql and apache. Very low load (3-4 clients).
> >
> >RAID: Yes, soft RAID1 between the 2 disks.
> >
> >I have times when the console freeze for 3-4 seconds!
> >2.6.0-test11 had the same problem (maybe longer times).
> >2.6.1-rc2 worked good in this respect but crashed after 2 days. :(
> >2.6.2-rc2 is back with the delay.
> >
> >Do you know why this can happen?
> >
> >
> 
> There haven't been many scheduler changes there recently so
> maybe its something else.
> 
> But you could try the latest -mm kernels. They have some
> Hyperthreading work in them (you need to enable CONFIG_SCHED_SMT).
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-smp" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

-- 
Robert M. Hyatt, Ph.D.          Computer and Information Sciences
hyatt@uab.edu                   University of Alabama at Birmingham
(205) 934-2213                  136A Campbell Hall
(205) 934-5473 FAX              Birmingham, AL 35294-1170

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Catalin BOIE]

On Thu, 29 Jan 2004, Robert M. Hyatt wrote:

>
>
> It might be some IDE disk I/O that results from flushing buffers or
> whatever.  I don't see this on my SCSI boxes, but I have seen an IDE
> box get sluggish at times due to I/O.

It is possible.
vmstat shows a lot of writes when this happen.
Seems that even reads hangs.
I remember tat I was in pine and I tried to save a small file (under 1k)
and it took 5-7 seconds to do it.

>
> On Thu, 29 Jan 2004, Nick Piggin
> wrote:
>
> >
> >
> > Catalin BOIE wrote:
> >
> > >Hello!
> > >
> > >First, thank you very much for the effort you put for Linux!
> > >
> > >I have a Intel motherboard with SATA (2 Maxtor disks).
> > >CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
> > >1 GB RAM.
> > >
> > >Load: postgresql and apache. Very low load (3-4 clients).
> > >
> > >RAID: Yes, soft RAID1 between the 2 disks.
> > >
> > >I have times when the console freeze for 3-4 seconds!
> > >2.6.0-test11 had the same problem (maybe longer times).
> > >2.6.1-rc2 worked good in this respect but crashed after 2 days. :(
> > >2.6.2-rc2 is back with the delay.
> > >
> > >Do you know why this can happen?
> > >
> > >
> >
> > There haven't been many scheduler changes there recently so
> > maybe its something else.
> >
> > But you could try the latest -mm kernels. They have some
> > Hyperthreading work in them (you need to enable CONFIG_SCHED_SMT).
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-smp" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
>
> --
> Robert M. Hyatt, Ph.D.          Computer and Information Sciences
> hyatt@uab.edu                   University of Alabama at Birmingham
> (205) 934-2213                  136A Campbell Hall
> (205) 934-5473 FAX              Birmingham, AL 35294-1170
>

---
Catalin(ux) BOIE
catab@deuroconsult.ro

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Gene Heskett]

On Friday 30 January 2004 02:25, Catalin BOIE wrote:
>On Thu, 29 Jan 2004, Robert M. Hyatt wrote:
>> It might be some IDE disk I/O that results from flushing buffers
>> or whatever.  I don't see this on my SCSI boxes, but I have seen
>> an IDE box get sluggish at times due to I/O.
>
>It is possible.
>vmstat shows a lot of writes when this happen.
>Seems that even reads hangs.
>I remember tat I was in pine and I tried to save a small file (under
> 1k) and it took 5-7 seconds to do it.
>
I'm having similar problems with kmail on the later kernels. Sometimes 
it works just fine, and in the middle of typing a nessage it can get 
laggy as hell, cursor motions with the arrow keys are down to 1 space 
a second, and gkrellm is saying the user apps are at 100% cpu.  
Screen redraws for a page up or page down might take 3 or 4 seconds.
Or it can get over it. (sometimes)

>> On Thu, 29 Jan 2004, Nick Piggin
>>
>> wrote:
>> > Catalin BOIE wrote:
>> > >Hello!
>> > >
>> > >First, thank you very much for the effort you put for Linux!
>> > >
>> > >I have a Intel motherboard with SATA (2 Maxtor disks).
>> > >CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
>> > >1 GB RAM.
>> > >
>> > >Load: postgresql and apache. Very low load (3-4 clients).
>> > >
>> > >RAID: Yes, soft RAID1 between the 2 disks.
>> > >
>> > >I have times when the console freeze for 3-4 seconds!
>> > >2.6.0-test11 had the same problem (maybe longer times).
>> > >2.6.1-rc2 worked good in this respect but crashed after 2 days.
>> > > :( 2.6.2-rc2 is back with the delay.
>> > >
>> > >Do you know why this can happen?
>> >
>> > There haven't been many scheduler changes there recently so
>> > maybe its something else.
>> >
>> > But you could try the latest -mm kernels. They have some
>> > Hyperthreading work in them (you need to enable
>> > CONFIG_SCHED_SMT).
>> >
>> > -
>> > To unsubscribe from this list: send the line "unsubscribe
>> > linux-smp" in the body of a message to majordomo@vger.kernel.org
>> > More majordomo info at 
>> > http://vger.kernel.org/majordomo-info.html
>>
>> --
>> Robert M. Hyatt, Ph.D.          Computer and Information Sciences
>> hyatt@uab.edu                   University of Alabama at
>> Birmingham (205) 934-2213                  136A Campbell Hall
>> (205) 934-5473 FAX              Birmingham, AL 35294-1170
>
>---
>Catalin(ux) BOIE
>catab@deuroconsult.ro
>-
>To unsubscribe from this list: send the line "unsubscribe
> linux-kernel" in the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty: soap,
ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.22% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attornies please note, additions to this message
by Gene Heskett are:
Copyright 2004 by Maurice Eugene Heskett, all rights reserved.

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Andrew Morton]

Gene Heskett <gene.heskett@verizon.net> wrote:
>
> On Friday 30 January 2004 02:25, Catalin BOIE wrote:
> >On Thu, 29 Jan 2004, Robert M. Hyatt wrote:
> >> It might be some IDE disk I/O that results from flushing buffers
> >> or whatever.  I don't see this on my SCSI boxes, but I have seen
> >> an IDE box get sluggish at times due to I/O.
> >
> >It is possible.
> >vmstat shows a lot of writes when this happen.
> >Seems that even reads hangs.
> >I remember tat I was in pine and I tried to save a small file (under
> > 1k) and it took 5-7 seconds to do it.
> >
> I'm having similar problems with kmail on the later kernels.

There's a problem with reiserfs and kmail.  If you're using reiserfs, be
sure to have the latest kmail installed, or mount the filesytems with
`nolargeio=1'.

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Bill Davidsen]

Catalin BOIE wrote:
> On Thu, 29 Jan 2004, Robert M. Hyatt wrote:
> 
> 
>>
>>It might be some IDE disk I/O that results from flushing buffers or
>>whatever.  I don't see this on my SCSI boxes, but I have seen an IDE
>>box get sluggish at times due to I/O.
> 
> 
> It is possible.
> vmstat shows a lot of writes when this happen.
> Seems that even reads hangs.
> I remember tat I was in pine and I tried to save a small file (under 1k)
> and it took 5-7 seconds to do it.
> 
> 
>>On Thu, 29 Jan 2004, Nick Piggin
>>wrote:
>>
>>
>>>
>>>Catalin BOIE wrote:
>>>
>>>
>>>>Hello!
>>>>
>>>>First, thank you very much for the effort you put for Linux!
>>>>
>>>>I have a Intel motherboard with SATA (2 Maxtor disks).
>>>>CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
>>>>1 GB RAM.
>>>>
>>>>Load: postgresql and apache. Very low load (3-4 clients).
>>>>
>>>>RAID: Yes, soft RAID1 between the 2 disks.
>>>>
>>>>I have times when the console freeze for 3-4 seconds!
>>>>2.6.0-test11 had the same problem (maybe longer times).
>>>>2.6.1-rc2 worked good in this respect but crashed after 2 days. :(
>>>>2.6.2-rc2 is back with the delay.
>>>>
>>>>Do you know why this can happen?
>>>>
>>>>
>>>
>>>There haven't been many scheduler changes there recently so
>>>maybe its something else.
>>>
>>>But you could try the latest -mm kernels. They have some
>>>Hyperthreading work in them (you need to enable CONFIG_SCHED_SMT).

Another possible improvement might come from the recent ide changes 
posted here for evaluation. There was a change to not block all devices 
or even all devices on a cable if one device delayed. I believe it was 
if a command didn't finish as intended, but I don't have it handy since 
I sent it off for testing tomorrow on a system which may have that problem.

There's a good bit of work on hangs happening right now, so you could 
wait or dig up the patches and try them. I think they were by Davin 
McCall if memory serves.


-- 
bill davidsen <davidsen@tmr.com>
   CTO TMR Associates, Inc
   Doing interesting things with small computers since 1979

Re: 2.6.2-rc2 Interactivity problems with SMP + HT

[Catalin BOIE]

> >>It might be some IDE disk I/O that results from flushing buffers or
> >>whatever.  I don't see this on my SCSI boxes, but I have seen an IDE
> >>box get sluggish at times due to I/O.
> >
> >
> > It is possible.
> > vmstat shows a lot of writes when this happen.
> > Seems that even reads hangs.
> > I remember tat I was in pine and I tried to save a small file (under 1k)
> > and it took 5-7 seconds to do it.
> >
> >
> >>On Thu, 29 Jan 2004, Nick Piggin
> >>wrote:
> >>
> >>
> >>>
> >>>Catalin BOIE wrote:
> >>>
> >>>
> >>>>Hello!
> >>>>
> >>>>First, thank you very much for the effort you put for Linux!
> >>>>
> >>>>I have a Intel motherboard with SATA (2 Maxtor disks).
> >>>>CPUs: 2 x 2.4GHz PIV HT = 4 processors (2 virtual)
> >>>>1 GB RAM.
> >>>>
> >>>>Load: postgresql and apache. Very low load (3-4 clients).
> >>>>
> >>>>RAID: Yes, soft RAID1 between the 2 disks.
> >>>>
> >>>>I have times when the console freeze for 3-4 seconds!
> >>>>2.6.0-test11 had the same problem (maybe longer times).
> >>>>2.6.1-rc2 worked good in this respect but crashed after 2 days. :(
> >>>>2.6.2-rc2 is back with the delay.
> >>>>
> >>>>Do you know why this can happen?
> >>>>
> >>>>
> >>>
> >>>There haven't been many scheduler changes there recently so
> >>>maybe its something else.
> >>>
> >>>But you could try the latest -mm kernels. They have some
> >>>Hyperthreading work in them (you need to enable CONFIG_SCHED_SMT).
>
> Another possible improvement might come from the recent ide changes
> posted here for evaluation. There was a change to not block all devices
> or even all devices on a cable if one device delayed. I believe it was
> if a command didn't finish as intended, but I don't have it handy since
> I sent it off for testing tomorrow on a system which may have that problem.
>
> There's a good bit of work on hangs happening right now, so you could
> wait or dig up the patches and try them. I think they were by Davin
> McCall if memory serves.

Thank you very much.

>
>
> --
> bill davidsen <davidsen@tmr.com>
>    CTO TMR Associates, Inc
>    Doing interesting things with small computers since 1979
>

---
Catalin(ux) BOIE
catab@deuroconsult.ro