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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-12-09 02:46:45 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-12-09 13:46:15 -0500 |
| commit | a73ed26bbae7327370c5bd298f07de78df9e3466 (patch) | |
| tree | 3c7a04e638261cdd16c324ecd07e303e72fac3b9 /include/net/red.h | |
| parent | 0221cd51543972782af558c527e4ac58b32049fa (diff) | |
| download | lwn-a73ed26bbae7327370c5bd298f07de78df9e3466.tar.gz lwn-a73ed26bbae7327370c5bd298f07de78df9e3466.zip | |
sch_red: generalize accurate MAX_P support to RED/GRED/CHOKE
Now RED uses a Q0.32 number to store max_p (max probability), allow
RED/GRED/CHOKE to use/report full resolution at config/dump time.
Old tc binaries are non aware of new attributes, and still set/get Plog.
New tc binary set/get both Plog and max_p for backward compatibility,
they display "probability value" if they get max_p from new kernels.
# tc -d qdisc show dev ...
...
qdisc red 10: parent 1:1 limit 360Kb min 30Kb max 90Kb ecn ewma 5
probability 0.09 Scell_log 15
Make sure we avoid potential divides by 0 in reciprocal_value(), if
(max_th - min_th) is big.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/red.h')
| -rw-r--r-- | include/net/red.h | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/include/net/red.h b/include/net/red.h index 24606b22d01e..ef715a16cce4 100644 --- a/include/net/red.h +++ b/include/net/red.h @@ -155,9 +155,10 @@ static inline u32 red_maxp(u8 Plog) static inline void red_set_parms(struct red_parms *p, u32 qth_min, u32 qth_max, u8 Wlog, u8 Plog, - u8 Scell_log, u8 *stab) + u8 Scell_log, u8 *stab, u32 max_P) { int delta = qth_max - qth_min; + u32 max_p_delta; /* Reset average queue length, the value is strictly bound * to the parameters below, reseting hurts a bit but leaving @@ -173,10 +174,14 @@ static inline void red_set_parms(struct red_parms *p, if (delta < 0) delta = 1; p->qth_delta = delta; - p->max_P = red_maxp(Plog); - p->max_P *= delta; /* max_P = (qth_max-qth_min)/2^Plog */ - - p->max_P_reciprocal = reciprocal_value(p->max_P / delta); + if (!max_P) { + max_P = red_maxp(Plog); + max_P *= delta; /* max_P = (qth_max - qth_min)/2^Plog */ + } + p->max_P = max_P; + max_p_delta = max_P / delta; + max_p_delta = max(max_p_delta, 1U); + p->max_P_reciprocal = reciprocal_value(max_p_delta); /* RED Adaptative target : * [min_th + 0.4*(min_th - max_th), @@ -380,6 +385,7 @@ static inline void red_adaptative_algo(struct red_parms *p) p->max_P = (p->max_P/10)*9; /* maxp = maxp * Beta */ max_p_delta = DIV_ROUND_CLOSEST(p->max_P, p->qth_delta); + max_p_delta = max(max_p_delta, 1U); p->max_P_reciprocal = reciprocal_value(max_p_delta); } #endif |