Re: HTT/SMP Dual Xeon systems unstable

2004-12-15 Thread John Baldwin
On Friday 10 December 2004 09:32 am, [EMAIL PROTECTED] 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 [EMAIL PROTECTED]http://www.FreeBSD.org/~jhb/
Power Users Use the Power to Serve  =  http://www.FreeBSD.org
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Re: HTT/SMP Dual Xeon systems unstable

2004-12-15 Thread Stephen Montgomery-Smith
John Baldwin wrote:
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.

It looks like I have lucked out so far, because I have this set up with 
no problems so far.  I hope this fix gets to 5.x-stable soon because for 
my particular workloads HTT helps a lot.

Stephen
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HTT/SMP Dual Xeon systems unstable

2004-12-10 Thread klr
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.

Regards,

Hugo

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