fcntl spinlock in Linux?

[J. Bruce Fields]

On Wed, Jan 30, 2013 at 03:25:27PM +0100, Volker Lendecke wrote:
> On Wed, Jan 30, 2013 at 09:18:53AM -0500, J. Bruce Fields wrote:
> > On Wed, Jan 30, 2013 at 08:32:47AM +0100, Volker Lendecke wrote:
> > > On Tue, Jan 29, 2013 at 05:03:58PM -0500, J. Bruce Fields wrote:
> > > > On Tue, Jan 29, 2013 at 10:51:33PM +0100, Volker Lendecke wrote:
> > > > > On Tue, Jan 29, 2013 at 04:37:03PM -0500, J. Bruce Fields wrote:
> > > > > > It's probably also easiest to fix.
> > > > > 
> > > > > Including deadlock detection? I guess this would have to
> > > > > look at all locks held by a thread, possibly on different
> > > > > inodes.
> > > > 
> > > > As a way of at least testing whether this is your problem, we could rip
> > > > out the deadlock detection entirely.
> > > 
> > > Depending on the workload, this is partly Samba's problem.
> > > Some real-world workloads imposed upon Samba make thousands
> > > of smbds contend on a single lock.
> > 
> > By the way, do you have a way to boil any of these down into simple test
> > cases that we could use?  (If it didn't even require installing Samba
> > that would be ideal.)
> 
> I could send you a statically linked tdbtorture binary. It
> is very easy to run that into the problems we are seeing.
> Would that help?

Oh, well, if that's all it needs, I built tdbtorture here (just
./configure && make from samba git on an F16 machine).  Hm, now what do
I do?:

	# ./bin/tdbtorture -h
	Usage: tdbtorture [-t] [-k] [-n NUM_PROCS] [-l NUM_LOOPS] [-s SEED] [-H HASH_SIZE]

Any recommended commandline, or any data you could share with expected
vs. actual results?

--b.

> 
> With best regards,
> 
> Volker Lendecke
> 
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