On Sep 4, 2009, at 16:49, Ben Greear <greearb@xxxxxxxxxxxxxxx> wrote:
I'm using O_DIRECT (so that the server is continually stressed even if
the file would have otherwise been cached locally on the client).
This still causes a copy of the contents to user-space when I do a
read() call though, as far as I can tell. Since I'm normally not
looking
at this data at all, the memory copy from kernel to user is wasted
effort in my case.
You're missing the point. O_DIRECT does not copy data from the kernel
into userspace. The data is placed directly into the user buffer from
the socket.
The only faster alternative would be to directly discard the data in
the socket, and we offer no option to do that.
Trond
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