Re: kern/37025 (mount_smbfs write performance is <censored>)

["Martin S. Weber" <Ephaeton%gmx.net@localhost>]

The following reply was made to PR kern/37025; it has been noted by GNATS.

From: "Martin S. Weber" <Ephaeton%gmx.net@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/37025 (mount_smbfs write performance is <censored>)
Date: Tue, 23 Mar 2010 15:29:37 -0400

 On Tue, Mar 23, 2010 at 05:30:04PM +0000, David Holland wrote:
 > The following reply was made to PR kern/37025; it has been noted by GNATS.
 > 
 > From: David Holland <dholland-bugs%netbsd.org@localhost>
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc: Ephaeton%gmx.net@localhost
 > Subject: Re: kern/37025 (mount_smbfs write performance is <censored>)
 > Date: Tue, 23 Mar 2010 17:29:04 +0000
 > 
 >  On Tue, Mar 23, 2010 at 01:55:02AM +0000, Martin S. Weber wrote:
 >   > Now where to go from here? I still believe there's a problem here, 
 >   > although the situation seriously improved in contrast to the eons
 >   > ago when I first filed this PR.
 >  
 >  Kernel profiling or fine-grained timing to figure out where the time
 >  is going? It is likely to be a pain.
 
 Hell yeah :) I'll also need a pointer on how to do that correctly please.
 
 >  
 >   >  Also the problem with random hangs of the mount persists. I haven't
 >   >  seen this happening with smbclient yet, only with a mount_smbfs-mounted
 >   >  share.
 >  
 >  Figuring out whether this is network-related (e.g. stalls due to lost
 >  packets, protocol botches, etc.) or vfs-related (lock
 >  contention/deadlock/etc.) might also be helpful. After all, the
 >  performance problem might be small instances of the same issue...
 >  
 >  ps -alx should be enough to diagnose this; look for something that
 >  isn't "tstile". ("tstile" just means "waiting for something else").
 
 I've written in an earlier reply to this PR that the stuck processes
 are sitting in smbwrq. I don't think it's network related, because they
 will sit there stalled until I do an ls in another shell on the share.
 Then, immediately (!), the writing/reading continues.
 Please let me know how I can furtherly try to diagnose a stalled
 transfer for locking problems or other vfs problems (pointer to howtos
 should do it).
 
 Also note that sometimes processes in smbwrq are unkillable (even with -9).
 
 Regards & TIA,
 
 -Martin