[CentOS] Intel Xeon and hyperthreading

Thu Jun 8 16:55:07 UTC 2006
William L. Maltby <BillsCentOS at triad.rr.com>

On Thu, 2006-06-08 at 11:32 -0500, Les Mikesell wrote:
> On Thu, 2006-06-08 at 11:33 -0400, Sam Drinkard wrote:
> 
> > <snip>


> A different algorithm, or something like pre-sorting the data might make
> a huge difference.

That can make a huge difference. My post mentioning the order of data
and keys is the "live" equivalent of exactly what Les mentions. Taken a
step further (if this is what you mean Les, sorry for repeating), it may
be possible to sequentially pre-read and sort (or pre-read in indexed
order) and feed that to the application *if* it has the ability to take
data from a sequential file or stream. *BIG* gains possible that way.

Further, if you have access to the source, or have tunable parameters
available (like size of each read call) and can achieve very large reads
of sequential data, system overhead (context switch, ...) is greatly
reduced. What does SAR show the split between user/system time being?
Might be a lot to gain there too.

HTH
-- 
Bill
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
URL: <http://lists.centos.org/pipermail/centos/attachments/20060608/7c4050c0/attachment-0005.sig>