BMC/Intel-BMC/linux.git/net/sched/sch_cbq.c, branch dev

net: sched: enable per cpu qstats

2014-09-30T05:02:26+00:00

After previous patches to simplify qstats the qstats can be made per cpu with a packed union in Qdisc struct. Signed-off-by: John Fastabend Signed-off-by: David S. Miller

net: sched: restrict use of qstats qlen

2014-09-30T05:02:26+00:00

This removes the use of qstats->qlen variable from the classifiers and makes it an explicit argument to gnet_stats_copy_queue(). The qlen represents the qdisc queue length and is packed into the qstats at the last moment before passnig to user space. By handling it explicitely we avoid, in the percpu stats case, having to figure out which per_cpu variable to put it in. It would probably be best to remove it from qstats completely but qstats is a user space ABI and can't be broken. A future patch could make an internal only qstats structure that would avoid having to allocate an additional u32 variable on the Qdisc struct. This would make the qstats struct 128bits instead of 128+32. Signed-off-by: John Fastabend Signed-off-by: David S. Miller

net: sched: implement qstat helper routines

2014-09-30T05:02:26+00:00

This adds helpers to manipulate qstats logic and replaces locations that touch the counters directly. This simplifies future patches to push qstats onto per cpu counters. Signed-off-by: John Fastabend Signed-off-by: David S. Miller

net: sched: make bstats per cpu and estimator RCU safe

2014-09-30T05:02:26+00:00

In order to run qdisc's without locking statistics and estimators need to be handled correctly. To resolve bstats make the statistics per cpu. And because this is only needed for qdiscs that are running without locks which is not the case for most qdiscs in the near future only create percpu stats when qdiscs set the TCQ_F_CPUSTATS flag. Next because estimators use the bstats to calculate packets per second and bytes per second the estimator code paths are updated to use the per cpu statistics. Signed-off-by: John Fastabend Signed-off-by: David S. Miller

net: sched: use pinned timers

2014-09-26T04:26:48+00:00

While using a MQ + NETEM setup, I had confirmation that the default timer migration ( /proc/sys/kernel/timer_migration ) is killing us. Installing this on a receiver side of a TCP_STREAM test, (NIC has 8 TX queues) : EST="est 1sec 4sec" for ETH in eth1 do tc qd del dev $ETH root 2>/dev/null tc qd add dev $ETH root handle 1: mq tc qd add dev $ETH parent 1:1 $EST netem limit 70000 delay 6ms tc qd add dev $ETH parent 1:2 $EST netem limit 70000 delay 8ms tc qd add dev $ETH parent 1:3 $EST netem limit 70000 delay 10ms tc qd add dev $ETH parent 1:4 $EST netem limit 70000 delay 12ms tc qd add dev $ETH parent 1:5 $EST netem limit 70000 delay 14ms tc qd add dev $ETH parent 1:6 $EST netem limit 70000 delay 16ms tc qd add dev $ETH parent 1:7 $EST netem limit 80000 delay 18ms tc qd add dev $ETH parent 1:8 $EST netem limit 90000 delay 20ms done We can see that timers get migrated into a single cpu, presumably idle at the time timers are set up. Then all qdisc dequeues run from this cpu and huge lock contention happens. This single cpu is stuck in softirq mode and cannot dequeue fast enough. 39.24% [kernel] [k] _raw_spin_lock 2.65% [kernel] [k] netem_enqueue 1.80% [kernel] [k] netem_dequeue 1.63% [kernel] [k] copy_user_enhanced_fast_string 1.45% [kernel] [k] _raw_spin_lock_bh By pinning qdisc timers on the cpu running the qdisc, we respect proper XPS setting and remove this lock contention. 5.84% [kernel] [k] netem_enqueue 4.83% [kernel] [k] _raw_spin_lock 2.92% [kernel] [k] copy_user_enhanced_fast_string Current Qdiscs that benefit from this change are : netem, cbq, fq, hfsc, tbf, htb. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: rcu-ify tcf_proto

2014-09-13T16:30:25+00:00

rcu'ify tcf_proto this allows calling tc_classify() without holding any locks. Updaters are protected by RTNL. This patch prepares the core net_sched infrastracture for running the classifier/action chains without holding the qdisc lock however it does nothing to ensure cls_xxx and act_xxx types also work without locking. Additional patches are required to address the fall out. Signed-off-by: John Fastabend Acked-by: Eric Dumazet Signed-off-by: David S. Miller

cbq: now_rt removal

2014-08-19T17:58:44+00:00

Now q->now_rt is identical to q->now and is not required anymore. Signed-off-by: Vasily Averin Signed-off-by: David S. Miller

cbq: incorrectly low bandwidth setting blocks limited traffic

2014-08-19T17:58:44+00:00

Mainstream commit f0f6ee1f70c4 ("cbq: incorrect processing of high limits") have side effect: if cbq bandwidth setting is less than real interface throughput non-limited traffic can delay limited traffic for a very long time. This happen because of q->now changes incorrectly in cbq_dequeue(): in described scenario L2T is much greater than real time delay, and q->now gets an extra boost for each transmitted packet. Accumulated boost prevents update q->now, and blocked class can wait very long time until (q->now >= cl->undertime) will be true again. To fix the problem the patch updates q->now on each cbq_update() call. L2T-related pre-modification q->now was moved to cbq_update(). My testing confirmed that it fixes the problem and did not discover any side-effects Fixes: f0f6ee1f70c4 ("cbq: incorrect processing of high limits") Signed-off-by: Vasily Averin Signed-off-by: David S. Miller

net_sched: return nla_nest_end() instead of skb->len

2014-03-13T19:39:20+00:00

nla_nest_end() already has return skb->len, so replace return skb->len with return nla_nest_end instead(). Signed-off-by: Yang Yingliang Signed-off-by: David S. Miller

net_sched: replace pr_warning with pr_warn

2013-12-31T18:50:56+00:00

Prefer pr_warn(... to pr_warning(... Signed-off-by: Yang Yingliang Signed-off-by: David S. Miller