Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs mount problems

Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs mount problems

[Mohammad Sadegh Sadri]

Hi all,

well I could bring up the grant's kernel on ml403 completely. the root file=
 system was over nfs.=20

when I use a 100mbits link for connection to ml403 , every thing is working=
 suitably.
but when I use a 1000mbits link, I see that ml403 gets ip address from dhcp=
 and mounts the root file system but can not go further , it stops with a m=
essage: "nfs server not responding ...." some thing like this.

when pinging to ml403 with 64 bytes packets, ping works fine for both of 10=
0 and 1000mbits links
but when I try to ping the board with 4000 bytes packets I notice that ml40=
3 on gigabit link can not answer to ping packets, however on 100mbit link e=
very thing works just fine.

any ideas?


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Re: Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs mount problems

[Ben Warren]

Hi Mohammad,

On Tue, 2007-05-29 at 14:41 +0000, Mohammad Sadegh Sadri wrote:
> Hi all,
> 
> well I could bring up the grant's kernel on ml403 completely. the root file system was over nfs. 
> 
> when I use a 100mbits link for connection to ml403 , every thing is working suitably.
> but when I use a 1000mbits link, I see that ml403 gets ip address from dhcp and mounts the root file system but can not go further , it stops with a message: "nfs server not responding ...." some thing like this.
> 
> when pinging to ml403 with 64 bytes packets, ping works fine for both of 100 and 1000mbits links
> but when I try to ping the board with 4000 bytes packets I notice that ml403 on gigabit link can not answer to ping packets, however on 100mbit link every thing works just fine.
> 
> any ideas?

NFS is notorious for sending lots of big packets one right after
another.  This can easily overwhelm an Ethernet receiver.  Until you're
able to figure out why the 1000M link can't keep up, limit the NFS
receive packet sizes by passing the following NFS option in your kernel
command line:

rsize=1024

You can experiment with the value.  I believe the NFS default size is
typically 8kB or greater.

regards,
Ben

Re: Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs mount problems

[Andrei Konovalov]

Mohammad Sadegh Sadri wrote:
> Hi all,
> 
> well I could bring up the grant's kernel on ml403 completely. the root file system was over nfs. 
> 
> when I use a 100mbits link for connection to ml403 , every thing is working suitably.
> but when I use a 1000mbits link, I see that ml403 gets ip address from dhcp and mounts the root file system but can not go further , it stops with a message: "nfs server not responding ...." some thing like this.
> 
> when pinging to ml403 with 64 bytes packets, ping works fine for both of 100 and 1000mbits links
> but when I try to ping the board with 4000 bytes packets I notice that ml403 on gigabit link can not answer to ping packets, however on 100mbit link every thing works just fine.
> 
> any ideas?

TEMAC is in FIFO mode?
Try adding "nfsroot=,rsize=1024,wsize=1024" to cmdline?

Thanks,
Andrei

RE: Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs mount problems

[Mohammad Sadegh Sadri]

Hi all,

thanks for suggestions
I added rsize=3D1024,wsize=3D1024 to CMD LINE. INIT can now be executed fro=
m nfs, but I think that the problem still exists,
during the start up process ( from when the rootfs is mounted until user ge=
t a command prompt ) some times ML403 stops working completely, and generat=
es "Segmentation Fault" and similar messages. some other times the system c=
omes up with no problem.=20

I had the same problem when mounting rootfs using nfs via 100mbits link , b=
ut for gigabit link the probability of reaching this unstable state is much=
 higher.

any ideas?

thanks




----------------------------------------
> Subject: Re: Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs=
	mount problems
> From: bwarren@qstreams.com
> To: mamsadegh@hotmail.com
> CC: linuxppc-embedded@ozlabs.org
> Date: Tue, 29 May 2007 10:52:21 -0400
>=20
> Hi Mohammad,
>=20
> On Tue, 2007-05-29 at 14:41 +0000, Mohammad Sadegh Sadri wrote:
> > Hi all,
> >=20
> > well I could bring up the grant's kernel on ml403 completely. the root =
file system was over nfs.=20
> >=20
> > when I use a 100mbits link for connection to ml403 , every thing is wor=
king suitably.
> > but when I use a 1000mbits link, I see that ml403 gets ip address from =
dhcp and mounts the root file system but can not go further , it stops with=
 a message: "nfs server not responding ...." some thing like this.
> >=20
> > when pinging to ml403 with 64 bytes packets, ping works fine for both o=
f 100 and 1000mbits links
> > but when I try to ping the board with 4000 bytes packets I notice that =
ml403 on gigabit link can not answer to ping packets, however on 100mbit li=
nk every thing works just fine.
> >=20
> > any ideas?
>=20
> NFS is notorious for sending lots of big packets one right after
> another.  This can easily overwhelm an Ethernet receiver.  Until you're
> able to figure out why the 1000M link can't keep up, limit the NFS
> receive packet sizes by passing the following NFS option in your kernel
> command line:
>=20
> rsize=3D1024
>=20
> You can experiment with the value.  I believe the NFS default size is
> typically 8kB or greater.
>=20
> regards,
> Ben
>=20

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RE: Kernel 2.6, ML403, rootfs on nfs, gigabit ethernet link, nfs mount problems

[Ben Warren]

--- Mohammad Sadegh Sadri <mamsadegh@hotmail.com> wrote:

> 
> Hi all,
> 
> thanks for suggestions
> I added rsize=1024,wsize=1024 to CMD LINE. INIT can now be executed from nfs,
> but I think that the problem still exists,
> during the start up process ( from when the rootfs is mounted until user get
> a command prompt ) some times ML403 stops working completely, and generates
> "Segmentation Fault" and similar messages. some other times the system comes
> up with no problem. 
> 
> I had the same problem when mounting rootfs using nfs via 100mbits link , but
> for gigabit link the probability of reaching this unstable state is much
> higher.
> 
> any ideas?
> 

Sorry, I don't know anything about your hardware.  Stating the obvious,
something's being put where it shouldn't be, maybe because the Ethernet driver
is filling buffers faster than they are being processed?  This is of course
stressed with a higher speed link.  You'll have much more control over your
debugging if you put rootfs somewhere other than NFS (flash or ramdisk), then
mount remote drives and try various file operations.

regards,
Ben