William Ahern wrote:
On Thu, Jul 10, 2008 at 02:20:33PM +0200, Valery Kholodkov wrote:
<snip>
As an example I have implemented asynchronous gzipper (see aio-test.c).
However I found, that this example does not outperform gzip, since
benefits of AIO appear themselfs only in specific conditions. One has to
deal with multiple buffers to get better performance, which is outside of
the scope of the example.
I wouldn't expect AIO to knock your socks off on Linux (and certainly not
*BSDs). Kernel support doesn't exist for AIO operating through the disk
buffer cache.
On my system (FreeBSD 7.0) I supposed to say "kldload aio" for this
patch to work. What kind of AIO support it is, if it is not a kernel?
When vmsplice() supports
nonblocking operations on files, that's probably when Linux will have
complete AIO support (both require similar capabilities). But don't hold
your breath; it requires significant changes in the VM subsystem of all
Unices to implement, nullifying over three decades of assumptions.
As I understand vmsplice() will never support nonblocking operations on
files, since vmsplice() requires fd to refer to a pipe, otherwise it
returns EBADF.
Perhaps Solaris or AIX has proper AIO support; I don't know.
AIO is the future, though. And it would be welcome to see support sooner
rather than later.
I don't think it is a future, I feel that AIO will become a reality in
the next few years, otherwise I wouldn't have written this patch.
--
Regards,
Valery Kholodkov
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