[CentOS] Intel Xeon and hyperthreading
Sam Drinkard
sam at wa4phy.net
Thu Jun 8 18:05:02 UTC 2006
William L. Maltby wrote:
>
>>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.
>
>
I don't think there is much in the way I can modify how the data is read
in. AFIK, it's all based on time data.
>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.
>
>
Sar reports 85% user, and about 9% system, with a current iowait of
0.27%, so there is not much wait to things.
>
>
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