Re: RHEL3 U4

The "improved" refers to better NUMA support.  Before U6, if you ran on 
a dualcore system in NUMA mode, and tried to grow a process beyond the 
size of a single node, it would begin swapping, i.e. the process 
couldn't grow across nodes.  The U6 kernel fixed this problem.

However, for RHEL3 we have *always* found that running in SMP mode (node 
interleaving ON, ACPI SRAT table OFF in the BIOS, and "numa=off" on 
kernel cmd line) yields a significant performance improvement.  When 
running in this mode, the NUMA support is irrelevant.  So I would say 
that you're *probably* OK with U4 on a dual-core box, so long as you 
disable NUMA.

Paul Krizak                         5900 E. Ben White Blvd. MS 625
Advanced Micro Devices              Austin, TX  78741
Linux/Unix Systems Engineering      Phone: (512) 602-8775
Silicon Design Division             Cell:  (512) 791-0686


Brian Long wrote:
> On Wed, 2007-08-01 at 12:11 +0800, Majumder, Rajib wrote:
>> Hi, 
>>   
>> I am wondering if RHEL3 Update 4 supports dual-core AMD Opteron CPUs.
>> My build is Update 4.   
>>   
>> 1) In which Update of RHEL3, dua-core CPU support was introduced? 
> 
> I believe this is a question best answered by your TAM (if you have
> one).  If you read the release notes for the various updates[1], you'll
> see that Update 6 introduced "improved" dual-core support.  They don't
> mention what improved means, but if you search through the changelog of
> the kernel RPM, there are significant improvements with regards to the
> scheduler.
> 
> /Brian/
> 
> 1. https://www.redhat.com/docs/manuals/enterprise/RHEL-3-Manual/


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