> While looking over the ehca driver from the perspective of adding a > "peek CQ" operation, I noticed some code that looked funny. > > In hipz_set_cqx_n0() and hipz_set_cqx_n1(), what is the point of the > calls to hipz_galpa_load_cq()? The return value is discarded. I see > that hipz_galpa_load_cq() dereferences a volatile pointer internally, > so I'm guessing this is some sort of ordering constraint. But would > it be just as good to do "barrier()" there? > > - R.
No, barrier won't help, the I/O bus connection is theoretically allowed to reorder and aggregate writes in a defined pattern. The recommended way to ensure that the ehca chip actually has seen the write is doing a read on the same address. Gruss / Regards . . . Christoph R _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
