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Add some initial bits (currently unused) for upcoming AMRR support.

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AMRR = Adaptive Multi Rate Retry algorithm
More information: http://www-sop.inria.fr/rapports/sophia/RR-5208.html
This commit is contained in:
damien 2005-11-15 17:48:49 +00:00
parent c5a63d4930
commit 1ea847bee2
1 changed files with 77 additions and 0 deletions
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77
sys/dev/usb/if_ural.c
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@ -2083,4 +2083,81 @@ ural_stop(void *priv)
ural_free_tx_list(sc);
}
/*-
* Naive implementation of the Adaptive Multi Rate Retry algorithm:
* "IEEE 802.11 Rate Adaptation: A Practical Approach"
* Mathieu Lacage, Hossein Manshaei, Thierry Turletti
* INRIA Sophia - Projet Planete
* http://www-sop.inria.fr/rapports/sophia/RR-5208.html
*
* This algorithm is particularly well suited for ural since it does not
* require per-frame retry statistics. Note however that since we do not
* have per-frame statistics, we cannot do per-node rate adaptation.
*/
#define URAL_AMRR_MIN_SUCCESS_THRESHOLD 1
#define URAL_AMRR_MAX_SUCCESS_THRESHOLD 10
#define is_success(amrr) \
((amrr)->retrycnt < (amrr)->txcnt / 10)
#define is_failure(amrr) \
((amrr)->retrycnt > (amrr)->txcnt / 3)
#define is_enough(amrr) \
((amrr)->txcnt > 10)
#define is_min_rate(ni) \
((ni)->ni_txrate == 0)
#define is_max_rate(ni) \
((ni)->ni_txrate == (ni)->ni_rates.rs_nrates - 1)
#define increase_rate(ni) \
((ni)->ni_txrate++)
#define decrease_rate(ni) \
((ni)->ni_txrate--)
#define reset_cnt(amrr) \
do { (amrr)->txcnt = (amrr)->retrycnt = 0; } while (0)
Static void ural_ratectl(void *) __unused;
Static void
ural_ratectl(void *priv)
{
struct ural_softc *sc = (struct ural_softc *)priv;
struct ieee80211com *ic = &sc->sc_ic;
struct ieee80211_node *ni = ic->ic_bss;
struct ural_amrr *amrr = &sc->amrr;
int need_change = 0;
if (is_success(amrr) && is_enough(amrr)) {
amrr->success++;
if (amrr->success >= amrr->success_threshold &&
!is_max_rate(ni)) {
amrr->recovery = 1;
amrr->success = 0;
increase_rate(ni);
need_change = 1;
} else {
amrr->recovery = 0;
}
} else if (is_failure(amrr)) {
amrr->success = 0;
if (!is_min_rate(ni)) {
if (amrr->recovery) {
amrr->success_threshold *= 2;
if (amrr->success_threshold >
URAL_AMRR_MAX_SUCCESS_THRESHOLD)
amrr->success_threshold =
URAL_AMRR_MAX_SUCCESS_THRESHOLD;
} else {
amrr->success_threshold =
URAL_AMRR_MIN_SUCCESS_THRESHOLD;
}
decrease_rate(ni);
need_change = 1;
}
amrr->recovery = 0; /* original paper was incorrect */
}
if (is_enough(amrr) || need_change)
reset_cnt(amrr);
}
DRIVER_MODULE(ural, uhub, ural_driver, ural_devclass, usbd_driver_load, 0);