Re: CVS commit: src/sys/dev/ic

[YAMAMOTO Takashi <yamt%mwd.biglobe.ne.jp@localhost>]

> > why doesn't WI_INTR include WI_EV_TX_EXC?
> 
> Right now, wi only uses WI_EV_TX_EXC to update the statistics counters.
> I think that if WI_INTRS contained WI_EV_TX_EXC, it would add to
> the interrupt overhead without gaining us a lot in the "timeliness"
> of statistics.
> 
> In a brief analysis, it did not look like the statistics can fall
> further behind than the maximum number of simultaneous outstanding
> transmissions, WI_NTXBUF (3), because we are guaranteed to see at least
> as many WI_EV_ALLOC (which generates an interrupt) as WI_EV_TX_EXC.
> 
> We will also occasionally "forget" as many as WI_NTXBUF Tx errors on
> interface up/down and also on change of media. I think that we would
> stand to miss a few even if WI_EV_TX_EXC was in WI_INTRS, however.
> 
> Let me know if my explanation is not satisfactory.

i see.  thanks for explanation.

YAMAMOTO Takashi