On Wed, Mar 31, 2010 at 8:57 PM, Roland Dreier wrote:
> > Processing the flag IB_CQ_REPORT_MISSED_EVENTS causes several IB
> > drivers to lock and unlock a spinlock. Full-speed SRP I/O can cause
> > this operation to be invoked more than 100.000 times a second, so the
> > flag IB_CQ_REPORT_MIS
> Processing the flag IB_CQ_REPORT_MISSED_EVENTS causes several IB
> drivers to lock and unlock a spinlock. Full-speed SRP I/O can cause
> this operation to be invoked more than 100.000 times a second, so the
> flag IB_CQ_REPORT_MISSED_EVENTS will have a small but measurable
> impact on SRP I/
On Wed, Mar 31, 2010 at 8:18 PM, Roland Dreier wrote:
>
> > The SRP initiator works fine without this patch, and this patch slows
> > down the SRP initiator.
>
> I do agree that there are no missed callbacks without this patch, but I
> don't see how it would slow things down... it seems to me it
> The SRP initiator works fine without this patch, and this patch slows
> down the SRP initiator.
I do agree that there are no missed callbacks without this patch, but I
don't see how it would slow things down... it seems to me it would avoid
some CQ event callbacks, especially for HCAs where
IB
On Wed, Mar 31, 2010 at 7:57 PM, Ralph Campbell
wrote:
>
> ib_req_notify_cq(IB_CQ_NEXT_COMP) is not guaranteed to generate
> a callback for the next completion entered since there is a race
> between arming the callback and another CQE being added to the queue.
> The IB_CQ_REPORT_MISSED_EVENTS fla
ib_req_notify_cq(IB_CQ_NEXT_COMP) is not guaranteed to generate
a callback for the next completion entered since there is a race
between arming the callback and another CQE being added to the queue.
The IB_CQ_REPORT_MISSED_EVENTS flag was added to detect this
race and allow the verbs consumer to ca
