[openib-general] [PATCH] use mmiowb after doorbell ring

[Roland Dreier]

    Roland> For now I just used lock; addl %0 to implement rmb on
    Roland> i386.  I'm really not comfortable making libmthca depend
    Roland> on sse2, and I don't see a good way to detect and use sse2
    Roland> at runtime.

    Jason> I think the typical way this is done would be to use
    Jason> ld.so's 'hwcap' handling and stick an optimized library in
    Jason> /usr/lib/sse2.

It's a good suggestion, but the problem is that the CPU-dependent code
is in the mthca.so driver-dependent plugin, which libibverbs dlopen()s
at runtime.  Do you know how to use the hwcap stuff with dlopen()?
I'm not thrilled about creating an sse2 special case in libibverbs
just to handle libmthca on i386.

 - R.