site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com On 01/06/2007, at 5:04 AM, James Bucanek <subscriber@gloaming.com>: I hadn't thought of that, and that's an excellent suggestion (thanks also extended to Brian and Matt). The source file data is only read once, so at least I can eliminate that from being cashed. Come to think of it, that might improve my overall performance since the reading the source file blocks also competes with the caching of my database file blocks. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com There's an even better reason why F_NOCACHE will probably improve your code's performance. Provided that you do as Quinn suggests with respect to alignment, it will cause the I/O to go directly to/from your user space buffer, removing the additional copy that happens in the buffered I/O case. This is why it's called "direct I/O" on most other platforms, where the O_DIRECT flag is used at file open time to enable it. Sam smime.p7s