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.
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.
Kris Kennaway 11 December 2004 00:41:56 [ permanent link ]
On Fri, Dec 10, 2004 at 05:58:06AM -0600, klr@6s-gaming.com wrote:> Hi,>
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?
It doesn't put the CPU to sleep in the idle loop, which can cause a performance loss in some cases, but also uses less power and generates less heat.
- HyperThreading - Do I really have a performance increase with HTT turned> on?
It depends on the workload you're doing. Try it and see.
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?
No.
- 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?
Only if the problem is with your machine, i.e. if you have a buggy BIOS. Don't discount this; look for an update from your vendor.
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?
It's quite possible. The release was made when it was and not earlier precisely because there were bugs in earlier versions.
John Baldwin 27 December 2004 23:57:06 [ permanent link ]
On Friday 10 December 2004 03:48 pm, Kris Kennaway wrote:> On Fri, Dec 10, 2004 at 05:58:06AM -0600, klr@6s-gaming.com wrote:> > 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?>
No.
Actually, for 5.3 it does. HEAD has the problem fixed, not sure about RELENG_5 yet, but due to the way IPIs are done in 5.3, having more than 2 CPUs can be very destabilizing, so disabling HTT on a 2-way system so that it goes from 4 CPUs to 2 CPUs can help stability very much.
