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On May 18, 2010, at 2:06 PM, Bill Bogstad wrote: > > Please re-read the end of my last message. Take a look at pread() > (POSIX) and readahead() (Linux only). > It turns out you do not need separate file handles. Threads may > still be required to make it non-blocking. I did look at pread(). While it doesn't reset the file handle's seek pointer it still effectively does a lseek() to the offset. So that's not really a performance win. > Not necessarily I would like random chunks of data from this file > (perhaps NEED it at some specific computation point in the future), > but I have some other computation I can do in the meantime. Please > start the disk IO now. Don't make me create multiple FDs for a single > file. At my option, I would like you to: This seems a little silly to me. I mean, if your processing takes more time then the reads then the hand-carved optimizations aren't a win. On the other hand, if they don't then the reads will block. If you aren't caching anything at that point then I think it's time to reconsider your storage format because this is a problem that's been solved before. --Rich P.
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