SMP performance on drgonfly

Erik Wikström erik-wikstrom at
Sat May 19 02:52:02 PDT 2007

On 2007-05-19 01:58, Kris Kennaway wrote:
On Fri, May 18, 2007 at 04:46:27PM -0700, Matthew Dillon wrote:
    A large chunk of the kernel still runs under the big giant
    lock, including the light weight processes that libthread_xu
    uses, so something like mysql is going to hit a lot of BGL
Oh, OK.

What subsystems are out from under the big giant lock, so I can look
for another benchmark to compare with?  Also, what profiling and
contention measurement tools do you have, so I can try to confirm that
this is the issue?
    You may be able to get DragonFly to run on the machines you
    were having problems with by compiling it with SMP but 
    without APIC_IO.  With that combination DragonFly will use
    the PIC in SMP mode, which usually works.
The issue is that I cannot even install with a UP kernel, so I can't
recompile to test this.  I posted with more details about this problem
a few months ago.
You should be able to build a new install CD, with the needed kernel 
options, on the computer where you got it running. Check out the 
nrelease framework for more details.

Erik Wikström

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