2002-09-16 22:49:53

by Richard Gooch

[permalink] [raw]
Subject: [BUG] NFS in 2.4.20-pre6+ stalls

Hi, all. Just noticed this with 2.4.20-pre6 (and -pre7): NFS write
sometimes (usually) stalls for minutes at a time. This problem wasn't
there on 2.4.19. I've noticed this when writing a files around 1 MiB
or so (some a bit larger, some a bit smaller). It makes NFS almost
unusable. I've appended the kernel logs which come, at no extra
charge, with the problem. On the server, I see partial files (integral
number of wsize= blocks) during the stall. Eventually, the client
seems to recover and the rest of the file is written. The writing
application is in TASK_INTERRUPTIBLE state.

Regards,

Richard....
Permanent: [email protected]
Current: [email protected]
===============================================================================
nfs: task 125 can't get a request slot
nfs: task 126 can't get a request slot
nfs: task 127 can't get a request slot
nfs: task 128 can't get a request slot
nfs: task 129 can't get a request slot
nfs: task 130 can't get a request slot
nfs: task 131 can't get a request slot
nfs: task 132 can't get a request slot
nfs: task 133 can't get a request slot
nfs: task 134 can't get a request slot
nfs: task 135 can't get a request slot
nfs: task 136 can't get a request slot
nfs: task 137 can't get a request slot
nfs: task 138 can't get a request slot
nfs: task 139 can't get a request slot
nfs: task 140 can't get a request slot
nfs: task 141 can't get a request slot
nfs: task 142 can't get a request slot
nfs: task 143 can't get a request slot
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK
nfs: server fileserver OK


2002-09-16 23:02:53

by Alan Cox

[permalink] [raw]
Subject: Re: [BUG] NFS in 2.4.20-pre6+ stalls

On Mon, 2002-09-16 at 23:54, Richard Gooch wrote:
> Hi, all. Just noticed this with 2.4.20-pre6 (and -pre7): NFS write
> sometimes (usually) stalls for minutes at a time. This problem wasn't
> there on 2.4.19. I've noticed this when writing a files around 1 MiB
> or so (some a bit larger, some a bit smaller). It makes NFS almost
> unusable. I've appended the kernel logs which come, at no extra

I've reported the same to Marcelo. Its there in a slightly different
form in my case - low bandwidth streaming data shows it up very well.

2002-09-17 18:44:02

by Bill Davidsen

[permalink] [raw]
Subject: Re: [BUG] NFS in 2.4.20-pre6+ stalls

On 17 Sep 2002, Alan Cox wrote:

> On Mon, 2002-09-16 at 23:54, Richard Gooch wrote:
> > Hi, all. Just noticed this with 2.4.20-pre6 (and -pre7): NFS write
> > sometimes (usually) stalls for minutes at a time. This problem wasn't
> > there on 2.4.19. I've noticed this when writing a files around 1 MiB
> > or so (some a bit larger, some a bit smaller). It makes NFS almost
> > unusable. I've appended the kernel logs which come, at no extra
>
> I've reported the same to Marcelo. Its there in a slightly different
> form in my case - low bandwidth streaming data shows it up very well.

This may explain why my favorite Internet radio station is acting up.

--
bill davidsen <[email protected]>
CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

2002-09-25 12:36:26

by Trond Myklebust

[permalink] [raw]
Subject: RE: [BUG] NFS in 2.4.20-pre6+ stalls

> Hi, all. Just noticed this with 2.4.20-pre6 (and -pre7): NFS write
> sometimes (usually) stalls for minutes at a time. This problem wasn't

Richard,
Does the appended patch make a difference?

Cheers,
Trond


Attachments:
resend.dif (910.00 B)

2002-09-25 15:25:28

by Richard Gooch

[permalink] [raw]
Subject: RE: [BUG] NFS in 2.4.20-pre6+ stalls

Trond Myklebust writes:
> > Hi, all. Just noticed this with 2.4.20-pre6 (and -pre7): NFS write
> > sometimes (usually) stalls for minutes at a time. This problem wasn't
>
> Richard,
> Does the appended patch make a difference?

Monday afternoon (my time) I grabbed the current BK tree and have been
using it since then. The problem has been reduced. I thought it was
fixed, but just as I sent this message, I tried my little test again,
and in one of the three runs I had a 21 second stall. I waited a few
minutes between tests.

Is your patch meant for the latest BK tree? Or something older?

Regards,

Richard....
Permanent: [email protected]
Current: [email protected]

2002-09-26 11:24:17

by Trond Myklebust

[permalink] [raw]
Subject: RE: [BUG] NFS in 2.4.20-pre6+ stalls

>>>>> " " == Richard Gooch <[email protected]> writes:

> Monday afternoon (my time) I grabbed the current BK tree and
> have been using it since then. The problem has been reduced. I
> thought it was fixed, but just as I sent this message, I tried
> my little test again, and in one of the three runs I had a 21
> second stall. I waited a few minutes between tests.

> Is your patch meant for the latest BK tree? Or something older?

The patch should apply fine to the latest BK tree: there have been no
recent changes that might affect it.

Cheers,
Trond

2002-09-28 22:38:40

by Richard Gooch

[permalink] [raw]
Subject: RE: [BUG] NFS in 2.4.20-pre6+ stalls

Trond Myklebust writes:
> >>>>> " " == Richard Gooch <[email protected]> writes:
>
> > Monday afternoon (my time) I grabbed the current BK tree and
> > have been using it since then. The problem has been reduced. I
> > thought it was fixed, but just as I sent this message, I tried
> > my little test again, and in one of the three runs I had a 21
> > second stall. I waited a few minutes between tests.
>
> > Is your patch meant for the latest BK tree? Or something older?
>
> The patch should apply fine to the latest BK tree: there have been no
> recent changes that might affect it.

Well, your patch doesn't make things worse. I tried to reproduce the
problem again, but couldn't. I'm running 2.4.20-pre8 plus your patch,
and will keep an eye on it.

Regards,

Richard....
Permanent: [email protected]
Current: [email protected]