On 2007-05-19, Erik Wikström <[EMAIL PROTECTED]> wrote: > 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 >>> contention. >> >> 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.
I dont think it is likely that Matt's suggestion will work given that UP kernels do not boot, indicating it's not an SMP APIC issue. Also now that I have this other machine running I don't currently have a motivation to try on 8-core AMD machines. I was hoping that Matt would reply to my questions above so I could try to find a more level playing field on which to compare Dragonfly and FreeBSD, but I'm afraid that the answer is that there currently are *no* kernel subsystems that are not Giant-locked, so all workloads will perform poorly on DragonFly (and there are no specialized tools for studying SMP behaviour -- certainly I couldn't find any when I looked). Can someone confirm whether this is true? Kris
