[ofa-general] fast path operation?

[Yicheng Jia]

Hi Roland,

I got another question about your code for mthca HCA. In the 
"mthca_provider.c", the functions "mthca_create_cq(struct ib_device 
*ibdev, int entries, struct ib_ucontext *context, struct ib_udata *udata)" 
and "mthca_alloc_pd(struct ib_device *ibdev, struct ib_ucontext *context, 
struct ib_udata *udata)" all have a parameter "ib_ucontext*", while in the 
"Verbs.c", the calling functions "ib_create_cq" and "ib_alloc_pd" all pass 
"NULL" to this parameter, is the " ib_ucontext *" only needed for fast 
path operation, in which situation the user application can write directly 
to user space? If it's true, how to set up the fast path operation in the 
driver environment?

Thanks!
Yicheng




Roland Dreier <rdreier at cisco.com> 
01/04/2008 02:45 PM

To
Yicheng Jia <YJia at tmriusa.com>
cc
general at lists.openfabrics.org, Jack Morgenstein <jackm at dev.mellanox.co.il>
Subject
Re: [ofa-general] synchronize commands issued to MTHCA






 > I'm using Duo-core Xeon and I just grep the source of "mmiowb()" in 
kernel 
 > 2.6.23 include/asm-x86_64 /io.h and found that this function does 
nothing 
 > on x86_64 platform, is it true?

Yes -- this is why I kept referring to large SGI Altix systems.

 - R.

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