Re: [Make-wifi-fast] [PATCH] killing retries harder, perhaps

["Toke Høiland-Jørgensen" <toke@toke.dk>]

Dave Taht <dave.taht@gmail.com> writes:

> ATH_TXMAXTRY is now unused.
>
> ATH_MAX_SW_RETRIES is insanely high by default.
>
> I finally have some good (well, horrible) data in a consistently noisy
> environment and would like to try knocking this down a little in a
> future test run. There's smarter ways to do it (like, if you are at
> the lowest rate, retry once, higher rates, 4).
>
> I have tried in the past values as low as 2 for soft retries.
>
> diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h
> b/drivers/net/wireless/ath/ath9k/ath9k.h
> index 331947b..304976d 100644
> --- a/drivers/net/wireless/ath/ath9k/ath9k.h
> +++ b/drivers/net/wireless/ath/ath9k/ath9k.h
> @@ -91,8 +91,7 @@ int ath_descdma_setup(struct ath_softc *sc, struct
> ath_descdma *dd,
>  #define ATH_RXBUF               512
>  #define ATH_TXBUF               512
>  #define ATH_TXBUF_RESERVE       5
> -#define ATH_TXMAXTRY            13
> -#define ATH_MAX_SW_RETRIES      30
> +#define ATH_MAX_SW_RETRIES      4

Note that this is not tested until *after* the initial retry chain has
been exhausted. So Minstrel may still (and usually will) define a retry
chain that is a lot longer than 4; meaning that the net effect of this
change is that you'll just drop any packets that are kicked back to the
driver after the retry chain fails... Not that this is necessarily a bad
thing, just something to keep in mind.

-Toke