Preload is a Linux daemon that stores commonly-used libraries and binaries in memory to speed up access times; similar to Windows Vista's SuperFetch function. This article looks at Preload and gives some insight into how much performance is gained for its total resource cost.
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Member since:2008-02-24
I guess a highly aggressive prefetch might cause problems. It's one thing to fill disk cache with potentially useful blocks just after booting--that's pretty harmless-- and another thing to start reading-in files for one application while another application is running because you expect the user to do it next. I think it all depends on how aggressive the prefetch is.
Member since:2007-07-26
You all seem to be confused. Preload uses RAM to cache recently used programs. Nothing I know of at the moment uses the hard drive to do this as it would be just as fast loading the program as you normally would. You guys may be thinking of swap space which is only used when you run out of available physical memory. If you run in to this situation while preload is running than I'm sure you will see a greater performance hit, but if this happens at any time than you will still be seeing a performance hit and preload running or not would be the least of your worries. RAM is cheap right now so stock up if this happens a lot.
Member since:
2008-02-24
Prefetch doesn't "waste disk cache". Disk cache starts empty and provides no boost until it gets content and begins to eliminate the need to physically read disk blocks. As you read-in blocks, it attempts to get rid of useless disk cache blocks based on a algorithm like "get rid of least recently used." The only way prefetch could hurt would be if the algorithm mistakenly thought there was a higher likelyhood the prefetched blocks would be used than some other recently read blocks. That is unlikely.