2 x quad-core system is slower that 2 x dual core on FreeBSD

Ivan Voras ivoras at freebsd.org
Thu Nov 22 06:24:17 PST 2007

Kris Kennaway wrote:
> Ivan Voras wrote:
>> On 21/11/2007, Kris Kennaway <kris at freebsd.org> wrote:
>>> Ivan Voras wrote:
>>>> Yes, but I had to verify it anyway :)
>>> You haven't verified anything until you look at how much work the system
>>> is doing, before and after.
>> I have, and it's roughly the same (50 +/- 2 queries/s).
>> (meaning that I'm not interested in exact statistics here, but in
>> order-of-magnitude changes, which didn't happen).
> OK, let's take a step back here.  Did you obtain the lock profiling
> trace and verify that you're seeing the same problem as Alexey?  Can I
> see the trace?

Here it is:


This is without your patch.

There's a lot of ZFS locks in there, but it seems lockmgr:ufs and
lockmgr:zfs have the largest records:

299117621   1474776121       148663     1042821  1414     0          513
         440 /usr/src/sys/kern/vfs_subr.c:2035 (lockmgr:ufs)

117958368    847566147       182093        2676 316728    68
948          374 /usr/src/sys/kern/vfs_vnops.c:515 (lockmgr:zfs)

Which is surprising since all the working-set file systems are on ZFS,
only the root and /tmp are on UFS. /tmp also holds sockets for the

Your reading of the lock profile will be appreciated.

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