On 2013-11-20 15:50, Karl Beldan wrote: > On Wed, Nov 20, 2013 at 03:04:34PM +0100, Felix Fietkau wrote: >> On 2013-11-20 14:56, Karl Beldan wrote: >> > On Wed, Nov 20, 2013 at 08:32:32AM +0100, Felix Fietkau wrote: >> >> On 2013-11-20 01:51, Karl Beldan wrote: >> >> > From: Karl Beldan <karl.beldan@xxxxxxxxxxxxxxxx> >> >> > >> >> > Commit 3e8b1eb "mac80211/minstrel_ht: improve rate selection stability" >> >> > introduced a local capped prob in minstrel_ht_calc_tp but omitted to use >> >> > it to compute the rate throughput. >> >> > >> >> > Signed-off-by: Karl Beldan <karl.beldan@xxxxxxxxxxxxxxxx> >> >> > CC: Felix Fietkau <nbd@xxxxxxxxxxx> >> >> Nice catch! >> >> Acked-by: Felix Fietkau <nbd@xxxxxxxxxxx> >> >> >> > Interestingly enough, consecutive coding rates (5/6, 3/4, 2/3) max ratio >> > is 9/10, did you do it on purpose ? (e.g. (9/10) * (5/6) == 3/4, >> > (9/10) * (3/4) == 2/3 + 11/120). >> The change has nothing to do with coding rates, it's only about >> retransmissions caused by collisions under load. >> > I understand this, my point was that along with this comes the following: > let's say my SNR is just not so good to get 5/6 as good as 3/4, and e.g. > case1 htMCS7 has 91% > htMCS6 has 100% success > case2 htMCS7 has 80% > htMCS6 has 100% success > capping at 90% will prefer htMCS7 in case1 and htMCS6 in case2 both > achieving best real throughput. > capping at 80% will prefer htMCS7 in case1 _but_ htMCS7 in case2 the > latter being the worst real throughput(90% of 5/6 == 100% of 3/4 > 80% > of 5/6). Not sure if that's a meaningful comparison at all - you're leaving out the per-packet overhead, which is important for the throughput calculation as well. - Felix -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
