From: Jonathan L. <la...@us...> - 2001-09-18 17:37:52
|
Jens Axboe [ax...@su...] wrote: > On Mon, Sep 17 2001, Jonathan Lahr wrote: > > > > > I would suggest you spend some > > > time checking how much of the contention is due to insertion scans and > > > how much is due to merge scans. > > > > I have already eliminated the contention problem by increasing concurrency > > through queue-specific locking. Lockmeter measurements with the patch > > applied indicate no need to examine the insertion code. > > "if an algorithm is broken, just fine grain the locking and everything > is perfect" > > That may be how you work elsewhere, but in Linux we like to do things > the other way around. Ok, let me help you out here. If it just so > happens that merging is what is eating lots of CPU cycles and thus the > primary contention problem, then we can probably fix that _without_ > changing the locking scope. I agree that contention could be reduced also by improving algorithmic efficiency. I'll look into that as well as an alternative to locking scope changes. The narrower scope of merge code improvement seems less risky than pervasive locking changes, but I'm not sure as much performance improvement can be made there. Thanks for your comments. Jonathan -- Jonathan Lahr IBM Linux Technology Center Beaverton, Oregon la...@us... 503-578-3385 |