| Message ID | 1454364016-3234-1-git-send-email-sven@open-mesh.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Johannes Berg |
| Headers | show |
Hi Sven, On Mon, Feb 01, 2016 at 11:00:16PM +0100, Sven Eckelmann wrote: > - tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * AVG_PKT_SIZE * 8 / 1024; > + tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10; > + tp_avg *= AVG_PKT_SIZE * 8 / 1024; This doesn't look right, in integer arithmetics there is a big difference between (a * b) / c and a * ( b / c). Johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c index 3ece7d1..b54f398 100644 --- a/net/mac80211/rc80211_minstrel.c +++ b/net/mac80211/rc80211_minstrel.c @@ -711,7 +711,7 @@ static u32 minstrel_get_expected_throughput(void *priv_sta) * computing cur_tp */ tmp_mrs = &mi->r[idx].stats; - tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_ewma); + tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx], tmp_mrs->prob_ewma) * 10; tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024; return tmp_cur_tp; diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c index 3928dbd..8928151 100644 --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -1334,7 +1334,8 @@ static u32 minstrel_ht_get_expected_throughput(void *priv_sta) prob = mi->groups[i].rates[j].prob_ewma; /* convert tp_avg from pkt per second in kbps */ - tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * AVG_PKT_SIZE * 8 / 1024; + tp_avg = minstrel_ht_get_tp_avg(mi, i, j, prob) * 10; + tp_avg *= AVG_PKT_SIZE * 8 / 1024; return tp_avg; }
The change from cur_tp to the function minstrel_get_tp_avg/minstrel_ht_get_tp_avg changed the unit used for the current throughput. For example in minstrel_ht the correct conversion between them would be: mrs->cur_tp / 10 == minstrel_ht_get_tp_avg(..). This factor 10 must also be included in the calculation of minstrel_get_expected_throughput and minstrel_ht_get_expected_throughput to return values with the unit [Kbps] instead of [10Kbps]. Otherwise routing algorithms like B.A.T.M.A.N. V will make incorrect decision based on these values. Its kernel based implementation expects expected_throughput always to have the unit [Kbps] and not sometimes [10Kbps] and sometimes [Kbps]. The same requirement has iw or olsrdv2's nl80211 based statistics module which retrieve the same data via NL80211_STA_INFO_TX_BITRATE. Fixes: 6a27b2c40b48 ("mac80211: restructure per-rate throughput calculation into function") Signed-off-by: Sven Eckelmann <sven@open-mesh.com> --- v3: - fix typo in title - extend description to better explain why this is important v2: - Modified PATCH title --- net/mac80211/rc80211_minstrel.c | 2 +- net/mac80211/rc80211_minstrel_ht.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)