dtrace discuss - Jan 2009 - nfsv3 provider: "failed to grab process"

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hi,

i''m trying to use the nfsv3 provider on S10U6, with the following
simple
script:

	#! /usr/sbin/dtrace -s
	#pragma D option quiet
	nfsv3:::op-read-start {
		printf("%s\n", args[1]->noi_curpath);
	}

however, when running it, i get the following error:

	dtrace: failed to compile script ./nfs2.d: line 5: failed to grab process 3

pid 3 is fsflush:

	 UID   PID  PPID   C    STIME TTY         TIME CMD
	root     3     0   1   Nov 13 ?        1663:31 fsflush

what am i doing wrong?

thanks,
river.
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fsflush isn''t a real process.  it''s actually a bunch of kernel
threads
that look like a processes so it can''t be grabbed / stopped.

ed

On Wed, Jan 21, 2009 at 07:48:21PM +0000, River Tarnell
wrote:
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>
> hi,
>
> i''m trying to use the nfsv3 provider on S10U6, with the following
simple
> script:
>
> 	#! /usr/sbin/dtrace -s
> 	#pragma D option quiet
> 	nfsv3:::op-read-start {
> 		printf("%s\n", args[1]->noi_curpath);
> 	}
>
> however, when running it, i get the following error:
>
> 	dtrace: failed to compile script ./nfs2.d: line 5: failed to grab process
3
>
> pid 3 is fsflush:
>
> 	 UID   PID  PPID   C    STIME TTY         TIME CMD
> 	root     3     0   1   Nov 13 ?        1663:31 fsflush
>
> what am i doing wrong?
>
> thanks,
> river.
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>
> iD8DBQFJd3wFIXd7fCuc5vIRAgcTAKCjExedEOKNlsZl63yLzZeyXz/HyACgqZY3
> gko1vjR33bZqsorMIdvMidg> =Jmcf
> -----END PGP SIGNATURE-----
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org

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Edward Pilatowicz:
> fsflush isn''t a real process.  it''s actually a bunch of
kernel threads
> that look like a processes so it can''t be grabbed / stopped.
this was my understanding - which makes me wonder why dtrace is trying to do so
in the first place.  (i haven''t specified a particular pid.)

	- river.
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Hi River,

It appears that there is no nfsv3 provider on your system. What do you see
when you do: dtrace -l | grep nfsv3?

Adam

On Wed, Jan 21, 2009 at 07:48:21PM +0000, River Tarnell
wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> hi,
> 
> i''m trying to use the nfsv3 provider on S10U6, with the following
simple
> script:
> 
> 	#! /usr/sbin/dtrace -s
> 	#pragma D option quiet
> 	nfsv3:::op-read-start {
> 		printf("%s\n", args[1]->noi_curpath);
> 	}
> 
> however, when running it, i get the following error:
> 
> 	dtrace: failed to compile script ./nfs2.d: line 5: failed to grab process
3
> 
> pid 3 is fsflush:
> 
> 	 UID   PID  PPID   C    STIME TTY         TIME CMD
> 	root     3     0   1   Nov 13 ?        1663:31 fsflush
> 
> what am i doing wrong?
> 
> thanks,
> river.
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> 
> iD8DBQFJd3wFIXd7fCuc5vIRAgcTAKCjExedEOKNlsZl63yLzZeyXz/HyACgqZY3
> gko1vjR33bZqsorMIdvMidg> =Jmcf
> -----END PGP SIGNATURE-----
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
-- 
Adam Leventhal, Fishworks                     http://blogs.sun.com/ahl

On Wed, Jan 21, 2009 at 3:41 PM, River Tarnell
<river at loreley.flyingparchment.org.uk> wrote:
> Edward Pilatowicz:
>> fsflush isn''t a real process.  it''s actually a bunch
of kernel threads
>> that look like a processes so it can''t be grabbed / stopped.
>
> this was my understanding - which makes me wonder why dtrace is trying to
do so
> in the first place.  (i haven''t specified a particular pid.)
Does this box have nfsv3 probes at all?  what does "dtrace -ln
''nfsv3:::''" report?

If I run this on a box without nfsv3 probes, I see the same thing you
do.  If I run that on a box with a recent build, I get this:

# dtrace -ln ''nfsv3:::''
   ID   PROVIDER            MODULE                          FUNCTION NAME
dtrace: failed to match nfsv3:::: No probe matches description
#

It looks like DTrace is parsing this as a USDT provider and trying to
grab pid 3 for the ''nfsv'' provider.

Chad

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hi,

thanks everyone - it seems S10 doesn''t have the nfsv3 provider yet.

root at ms1:~# dtrace -l | grep nfsv3
root at ms1:~# 

so, is there any other way to dtrace NFS operations?  i''d like to
aggregate at
least by access type (read/write), filename and client IP address.

thanks,
river.
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Hey River,

You can use the fbt provider to make some progress:

# dtrace -n fbt::rfs3_*:entry

 From there, you can pick apart the arguments to get at the data you  
need. If you need more help, please send another note to the list.  
You''ll definitely want to be looking at the source code; e.g.

http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/nfs/nfs3_srv.c#1240

Adam

On Jan 22, 2009, at 3:14 AM, River Tarnell wrote:
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>
> hi,
>
> thanks everyone - it seems S10 doesn''t have the nfsv3 provider
yet.
>
> root at ms1:~# dtrace -l | grep nfsv3
> root at ms1:~#
>
> so, is there any other way to dtrace NFS operations?  i''d like to
> aggregate at
> least by access type (read/write), filename and client IP address.
>
> thanks,
> river.
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> OvhtxEHBEv+V1DMNeTERMDE> =HfdA
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> dtrace-discuss at opensolaris.org

--
Adam Leventhal, Fishworks                        http://blogs.sun.com/ahl