Messages in this thread | | | Date | Thu, 8 Feb 2001 08:57:33 -0500 (EST) | From | Ben LaHaise <> | Subject | Re: select() returning busy for regular files [was Re: [Kiobuf-io-devel] RFC: Kernel mechanism: Compound event wait] |
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On Thu, 8 Feb 2001, Pavel Machek wrote:
> Hi! > > > > Its arguing against making a smart application block on the disk while its > > > able to use the CPU for other work. > > > > There are currently no other alternatives in user space. You'd have to > > create whole new interfaces for aio_read/write, and ways for the kernel to > > inform user space that "now you can re-try submitting your IO". > > Why is current select() interface not good enough?
Think of random disk io scattered across the disk. Think about aio_write providing a means to perform zero copy io without needing to resort to playing mm tricks write protecting pages in the user's page tables. It's also a means for dealing efficiently with thousands of outstanding requests for network io. Using a select based interface is going to be an ugly kludge that still has all the overhead of select/poll.
-ben
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