Message: 6
Date: Wed, 16 Aug 2006 16:23:18 -0400
From: Matthew Miller <mattdm@xxxxxxxxxx>
Subject: Re: SMP Kernel on non-SMP Machine
To: For users of Fedora Core releases <fedora-list@xxxxxxxxxx>
Message-ID: <20060816202318.GC18410@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=us-ascii
On Wed, Aug 16, 2006 at 02:09:20PM -0600, Ski Dawg wrote:
> Now, we used to do this at work (on RHEL) without any problems. We also
> installed the SMP kernel on machines that were single processor with no
> hyperthreading. We did this so that developers were working with the
> same kernel, no matter which machine they were using. Everything ran
> just fine with the SMP kernel on all the machines.
In fact, if your processor has the "nx" bit (look in the "flags") line in
/proc/cpuinfo, you will get a performance increase in system calls by using
the SMP kernel even on single-processor systems. I don't recall the
particulars of this, but there was a thread on fedora-devel a while ago
about it if you care to search. (This is one reason SMP is enabled in all
kernels in FC6.)
--
Matthew Miller mattdm@xxxxxxxxxx <http://mattdm.org/>
Boston University Linux ------> <http://linux.bu.edu/>
Thanks for the help. The processor is a hyperthreading processor.
I do not have the "nx" flag in /proc/cpuinfo. Here is the output for one of the CPUs since the listing are virtually identical.
processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Pentium(R) 4 CPU 2.80GHz
stepping : 5
cpu MHz : 2793.303
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr
bogomips : 5586.39
I got my self into this problem because I downloaded kernel.devel to build a VPN client not realizing there was a separrate source code for the SMP kernel. Needless to say, I could not install the module I built and went looking for the culprit.
Wes.
Date: Wed, 16 Aug 2006 16:23:18 -0400
From: Matthew Miller <mattdm@xxxxxxxxxx>
Subject: Re: SMP Kernel on non-SMP Machine
To: For users of Fedora Core releases <fedora-list@xxxxxxxxxx>
Message-ID: <20060816202318.GC18410@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=us-ascii
On Wed, Aug 16, 2006 at 02:09:20PM -0600, Ski Dawg wrote:
> Now, we used to do this at work (on RHEL) without any problems. We also
> installed the SMP kernel on machines that were single processor with no
> hyperthreading. We did this so that developers were working with the
> same kernel, no matter which machine they were using. Everything ran
> just fine with the SMP kernel on all the machines.
In fact, if your processor has the "nx" bit (look in the "flags") line in
/proc/cpuinfo, you will get a performance increase in system calls by using
the SMP kernel even on single-processor systems. I don't recall the
particulars of this, but there was a thread on fedora-devel a while ago
about it if you care to search. (This is one reason SMP is enabled in all
kernels in FC6.)
--
Matthew Miller mattdm@xxxxxxxxxx <http://mattdm.org/>
Boston University Linux ------> <http://linux.bu.edu/>
Thanks for the help. The processor is a hyperthreading processor.
I do not have the "nx" flag in /proc/cpuinfo. Here is the output for one of the CPUs since the listing are virtually identical.
processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Intel(R) Pentium(R) 4 CPU 2.80GHz
stepping : 5
cpu MHz : 2793.303
cache size : 512 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid xtpr
bogomips : 5586.39
I got my self into this problem because I downloaded kernel.devel to build a VPN client not realizing there was a separrate source code for the SMP kernel. Needless to say, I could not install the module I built and went looking for the culprit.
Wes.
