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On Tue, 10 Mar 1998, Scott Lampert wrote: > Far be it from me to criticize ideas made by those who know > much more than me, but personally I don't see how transfering stuff to swap > immediately instead of grabbing what ram we can from the disk > cache first could be considered faster or preferable. As far as > I can see, it would be much better performance-wise to delay swapping as > long as there's ram to be had from the disk cache. Isn't this the main > reason the disk cache is dynamic in size? When you just grab random disk cache memory, that piece of data might be needed again, and has to be reread from the (spread-out) filesystem. Swapping, OTOH, is done in a clustered way (less seek-time) on a small part of the disk (still less seek-time). I would be interested though, in the partition layout of the people who saw worse/better performance: begin end worse: data sys data swap better: data swap sys data ??? Maybe something like this could explain the difference. Personally, when I switched from swap at the far end of the disk to swap in the middle (somewhere autumn '95) I saw a _HUGE_ improvement. Now, I tend to tune my stuff for swap-in-the-middle situations, since I only have swap-in-the-middle as a test situation (and who wants to run with slow swap anyway?). If this explains the difference, I'll fix it by making page-aging tunable for the following categories: - user pages - cache pages - buffer pages - shared pages (?) Rik. +-------------------------------------------+--------------------------+ | Linux: - LinuxHQ MM-patches page | Scouting webmaster | | - kswapd ask-him & complain-to guy | Vries cubscout leader | | http://www.fys.ruu.nl/~riel/ | <H.H.vanRiel@fys.ruu.nl> | +-------------------------------------------+--------------------------+ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu | ||||||||||||
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