Re: CVS commit: src/tests/fs/common

[Nicolas Joly <njoly%pasteur.fr@localhost>]

On Mon, Mar 18, 2013 at 02:57:27PM -0400, Greg Troxel wrote:
> 
> Nicolas Joly <njoly%pasteur.fr@localhost> writes:
> 
> > The zfs tests are failing when run as an unprivileged user in
> > thread_create() ... because default limit for threads (160) is too
> > low ! When run as root, the limit value (2500) seems to be high enough.
> 
> So should we increase the default limits?  It's always a tough call to
> set limits for a large ensemble of hardware, big and small, but it also
> seems that limits should be big enough to run our test cases.

Another possibility would be to increase it locally, in the zfs test
code.

I just made some extra experiments with the following testcase :

  /usr/tests/fs/vfs/t_vnops:zfs_read_directory

And it seems that the needed thread number is over 260 ... and depends
on the number of virtual CPUs in the rump kernel which is the host
CPUs number by default.

  RUMP_NCPU=1  ... ulimit -r 261 ... ok
  RUMP_NCPU=2  ... ulimit -r 268 ... ok
  RUMP_NCPU=3  ... ulimit -r 275 ... ok
  RUMP_NCPU=4  ... ulimit -r 283 ... ok
  [...]
  RUMP_NCPU=8  ... ulimit -r 310 ... ok
  RUMP_NCPU=9  ... ulimit -r 317 ... ok
  RUMP_NCPU=10 ... ulimit -r 324 ... ok
  [...]

That make a 80 CPUs host require a thread limit value of 814
(=261+7*79) to be able to run this test.

-- 
Nicolas Joly

Biology IT Center
Institut Pasteur, Paris.