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authorEric Dumazet <edumazet@google.com>2017-09-13 21:16:45 +0300
committerDavid S. Miller <davem@davemloft.net>2017-09-13 23:30:53 +0300
commitca558e185972d8ecd308760abf972f5d408bcff0 (patch)
tree2edce2014072127cb43820fed3635ef5d6d4b6ec /net/core
parentd371465e81fc740cfa67ef47fbf692350c6b0113 (diff)
downloadlinux-ca558e185972d8ecd308760abf972f5d408bcff0.tar.xz
net_sched: gen_estimator: fix scaling error in bytes/packets samples
Denys reported wrong rate estimations with HTB classes. It appears the bug was added in linux-4.10, since my tests where using intervals of one second only. HTB using 4 sec default rate estimators, reported rates were 4x higher. We need to properly scale the bytes/packets samples before integrating them in EWMA. Tested: echo 1 >/sys/module/sch_htb/parameters/htb_rate_est Setup HTB with one class with a rate/cail of 5Gbit Generate traffic on this class tc -s -d cl sh dev eth0 classid 7002:11 class htb 7002:11 parent 7002:1 prio 5 quantum 200000 rate 5Gbit ceil 5Gbit linklayer ethernet burst 80000b/1 mpu 0b cburst 80000b/1 mpu 0b level 0 rate_handle 1 Sent 1488215421648 bytes 982969243 pkt (dropped 0, overlimits 0 requeues 0) rate 5Gbit 412814pps backlog 136260b 2p requeues 0 TCP pkts/rtx 982969327/45 bytes 1488215557414/68130 lended: 22732826 borrowed: 0 giants: 0 tokens: -1684 ctokens: -1684 Fixes: 1c0d32fde5bd ("net_sched: gen_estimator: complete rewrite of rate estimators") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/gen_estimator.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 0385dece1f6f..7c1ffd6f9501 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -83,10 +83,10 @@ static void est_timer(unsigned long arg)
u64 rate, brate;
est_fetch_counters(est, &b);
- brate = (b.bytes - est->last_bytes) << (8 - est->ewma_log);
+ brate = (b.bytes - est->last_bytes) << (10 - est->ewma_log - est->intvl_log);
brate -= (est->avbps >> est->ewma_log);
- rate = (u64)(b.packets - est->last_packets) << (8 - est->ewma_log);
+ rate = (u64)(b.packets - est->last_packets) << (10 - est->ewma_log - est->intvl_log);
rate -= (est->avpps >> est->ewma_log);
write_seqcount_begin(&est->seq);