Hi,
While we are at async i/o. I think direct i/o and concurrent i/o also deserve a look at. The archives suggest that Bruce had some misgivings about dio because of no kernel caching, but almost all databases seem to (carefully) use dio (Solaris, Linux, ?) and cio (AIX) extensively nowadays.
Since these can be turned on a per file basis, perf testing them out should be simpler too.
Regards,
Nikhils
On 10/25/06, Martijn van Oosterhout <kleptog@svana.org> wrote:On Tue, Oct 24, 2006 at 12:53:23PM -0700, Ron Mayer wrote:
> Anyway, for those who want to see what they do in Linux,
> http://www.gelato.unsw.edu.au/lxr/source/mm/fadvise.c
> Pretty scary that Bruce said it could make older linuxes
> dump core - there isn't a lot of code there.
The bug was probably in the glibc interface to the kernel. Google found
this:
http://sourceware.org/ml/libc-hacker/2004-03/msg00000.html
i.e. posix_fadvise appears to have been broken on all 64-bit
architechtures prior to March 2004 due to a silly linking error.
And then things like this:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=313219
Which suggest that prior to glibc 2.3.5, posix_fadvise crashed on 2.4
kernels. That's a fairly recent version, so the bug would still be
fairly widespead.
Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
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