On Sun, May 07, 2006 at 07:16:34PM +0100, Robert Watson wrote: > > On Sun, 7 May 2006, Sven Petai wrote: > > >I performed tests on a 4 * dualcore 2Ghz opteron system (so 8 cores in > >total). > > > >In general with 10 parallel smacker threads the performance seems to go up > >with your patch by ~44% and with 100 parallel threads it goes down ~25% > > This is an interesting effect I need to explore. Kris reported much > increased contention on locks within the process (between threads) when > running with my patch. It would be interesting to know what the effect on > average query time is -- perhaps it has gone down and we're looking at > increased scheduler related contention. > > I noticed the results in the tests seem somewhat variable. I've noticed > that MySQL bennchmarking is heavily affected by test run time and order. > It's not atypical when running a series of identical tests to see a first > result half the end rate, a second result *better* than the end rate, and > then it balance out between the two. For example, I see the following on a Also, I see a slow but statistically significant deterioration in performance over time. Maybe mysql's memory is getting fragmented or something. Kris
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