Date: Wed, 15 Dec 2004 09:58:48 -0500 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-smp@FreeBSD.org Cc: freebsd-questions@FreeBSD.org Subject: Re: HTT/SMP Dual Xeon systems unstable Message-ID: <200412150958.48432.jhb@FreeBSD.org> In-Reply-To: <56637.81.84.175.77.1102689148.squirrel@81.84.175.77> References: <56637.81.84.175.77.1102689148.squirrel@81.84.175.77>
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On Friday 10 December 2004 09:32 am, klr@6s-gaming.com wrote: > Hi, > > I'm sorry for typing this mail for the third time, I'm not sure if the > other mails did reach the list. The domain I was using to send emails has > just expired. Please cc me, as I'm not subscribed to the list with this > email. > > > I have a Dual Xeon 2.4 and a Dual Xeon 2.8 servers running with > HyperThreading, ACPI, and SMP enabled. > > The 2.8 server won't stand for more than 5 days without crashing, and the > 2.4 server was up 30 days crashed, now was up 12 days, and crashed. > > I didn't have a debugging kernel, I'll be building one when the datacenter > reboots the server. I also don't have any panic messages.. I have, > however, a few questions: > > - machdep.cpu_idle_hlt - I've seen a lot on google about this sysctl, but > still don't fully understand it. What does this sysctl really changes? > > - HyperThreading - Do I really have a performance increase with HTT turned > on? I've heard it can penalize performance because the scheduler isn't > optimized for logical CPUs. Does having HTT enabled impacts the stability > of the system? > > - ACPI - I'll be disabling ACPI along with HTT to see if the server > doesn't crash for awhile. Is ACPI on 5.3-STABLE (around November 1st, it > was pre-release) still a problem? > > Last but not the least, my 5.3-STABLE version is from a few days before > the release. Since I had created a few jails by then, I didn't upgrade the > system to use the -RELEASE. Was there any last-standing problem a few days > before the release that could be causing my instability problems? > > > Please share some common dual processor system knowledge, perhaps I'm > missing something really obvious and making these servers unstable. There is a problem in the kernel that causes with 3 or more processors (including logical CPUs from HTT). Disabling HTT in the BIOS is probably your best bet as it will get you down to 2 CPUs which should work much better. HTT also isn't but so useful anyways for most workloads. The instability problems have just been fixed in HEAD and will hopefully be MFC'd for 5.4 btw. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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