FAQ Search Today's Posts Mark Forums Read
» Video Reviews

» Linux Archive

Linux-archive is a website aiming to archive linux email lists and to make them easily accessible for linux users/developers.


» Sponsor

» Partners

» Sponsor

Go Back   Linux Archive > Debian > Debian Kernel

 
 
LinkBack Thread Tools
 
Old 08-20-2012, 03:46 AM
Ben Hutchings
 
Default Bug#681767: linux-image-3.2.0-3-rt-amd64: irq/23-eth0 high load

On Mon, 2012-07-16 at 10:48 +0000, Yevgeny Kosarhevsky wrote:
> Package: src
> Version: 3.2.21-3
> Severity: critical
> Justification: causes serious data loss

What data?

> Dear Maintainer,
> I get a heavy load on irq/23-eth0:
> 1086 root -51 0 0 0 0 S 2.0 0.0 0:31.04 irq/23-eth0

I don't think 2% CPU time is a 'heavy load'.

> This is only occured after upgrading from 2.6.32 kernel.
> The LA was 0.00 on previous kernel, now it's 1.44
[...]

But you are not comparing like with like. On a real-time kernel, IRQ
handlers are scheduled as tasks and are accounted in the load average.
On a standard kernel as you were running before, IRQ handlers are
accounted separately.

So, is there really a problem here? Did you actually mean to install a
real-time kernel?

Ben.

--
Ben Hutchings
The most exhausting thing in life is being insincere. - Anne Morrow Lindberg
 
Old 08-20-2012, 08:06 AM
Yevgeny Kosarzhevsky
 
Default Bug#681767: linux-image-3.2.0-3-rt-amd64: irq/23-eth0 high load

On Mon, 20 Aug 2012 04:46:53 +0100
Ben Hutchings <ben@decadent.org.uk> wrote:

> On Mon, 2012-07-16 at 10:48 +0000, Yevgeny Kosarhevsky wrote:
> > Package: src
> > Version: 3.2.21-3
> > Severity: critical
> > Justification: causes serious data loss
>
> What data?

My peers reported packet loss. Switching back to 2.6.32 kernel solved the issue.

> > Dear Maintainer,
> > I get a heavy load on irq/23-eth0:
> > 1086 root -51 0 0 0 0 S 2.0 0.0 0:31.04 irq/23-eth0
>
> I don't think 2% CPU time is a 'heavy load'.
>
> > This is only occured after upgrading from 2.6.32 kernel.
> > The LA was 0.00 on previous kernel, now it's 1.44
> [...]
>
> But you are not comparing like with like. On a real-time kernel, IRQ
> handlers are scheduled as tasks and are accounted in the load average.
> On a standard kernel as you were running before, IRQ handlers are
> accounted separately.
>
> So, is there really a problem here? Did you actually mean to install a
> real-time kernel?

Since there was a packet loss, I think there is a problem. I don't know if it's related with
> [ 1966.544292] NOHZ: local_softirq_pending 08
> [ 2108.848600] NOHZ: local_softirq_pending 08

--
Yevgeny Kosarzhevsky <phaoost@gmail.com>


--
To UNSUBSCRIBE, email to debian-kernel-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Archive: 20120820110654.01f46b96e92324c9bd028dac@gmail.com" >http://lists.debian.org/20120820110654.01f46b96e92324c9bd028dac@gmail.com
 
Old 08-20-2012, 12:27 PM
Ben Hutchings
 
Default Bug#681767: linux-image-3.2.0-3-rt-amd64: irq/23-eth0 high load

Control: retitle -1 rt: NAPI softirq not being scheduled properly
Control: tag -1 upstream

On Mon, 2012-08-20 at 11:06 +0300, Yevgeny Kosarzhevsky wrote:
> On Mon, 20 Aug 2012 04:46:53 +0100
> Ben Hutchings <ben@decadent.org.uk> wrote:
>
> > On Mon, 2012-07-16 at 10:48 +0000, Yevgeny Kosarhevsky wrote:
> > > Package: src
> > > Version: 3.2.21-3
> > > Severity: critical
> > > Justification: causes serious data loss
> >
> > What data?
>
> My peers reported packet loss. Switching back to 2.6.32 kernel solved the issue.

You must accept the risk of loss of data transmitted using UDP. The
phrase 'causes serious data loss' refers only to data in non-volatile
storage (or that is reported as having been stored there).

> > > Dear Maintainer,
> > > I get a heavy load on irq/23-eth0:
> > > 1086 root -51 0 0 0 0 S 2.0 0.0 0:31.04 irq/23-eth0
> >
> > I don't think 2% CPU time is a 'heavy load'.
> >
> > > This is only occured after upgrading from 2.6.32 kernel.
> > > The LA was 0.00 on previous kernel, now it's 1.44
> > [...]
> >
> > But you are not comparing like with like. On a real-time kernel, IRQ
> > handlers are scheduled as tasks and are accounted in the load average.
> > On a standard kernel as you were running before, IRQ handlers are
> > accounted separately.
> >
> > So, is there really a problem here? Did you actually mean to install a
> > real-time kernel?
>
> Since there was a packet loss, I think there is a problem. I don't know if it's
> related with
> > [ 1966.544292] NOHZ: local_softirq_pending 08
> > [ 2108.848600] NOHZ: local_softirq_pending 08

The number 08 apparently represents the NET_RX softirq, which is usually
responsible for receiving packets after a network interrupt (NAPI). And
this warning seems to mean that it is marked as pending, but somehow
hasn't been scheduled. So this is very likely related.

Ben.

--
Ben Hutchings
The most exhausting thing in life is being insincere. - Anne Morrow Lindberg
 

Thread Tools




All times are GMT. The time now is 04:29 PM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.
Copyright 2007 - 2008, www.linux-archive.org