In qdisc_run_end(), the spin_unlock() only has store-release semantic,
which guarantees all earlier memory access are visible before it. But
the subsequent test_bit() has no barrier semantics so may be reordered
ahead of the spin_unlock(). The store-load reordering may cause a packet
stuck problem.
The concurrent operations can be described as below,
CPU 0 | CPU 1
qdisc_run_end() | qdisc_run_begin()
. | .
----> /* may be reorderd here */ | .
| . | .
| spin_unlock() | set_bit()
| . | smp_mb__after_atomic()
---- test_bit() | spin_trylock()
. | .
Consider the following sequence of events:
CPU 0 reorder test_bit() ahead and see MISSED = 0
CPU 1 calls set_bit()
CPU 1 calls spin_trylock() and return fail
CPU 0 executes spin_unlock()
At the end of the sequence, CPU 0 calls spin_unlock() and does nothing
because it see MISSED = 0. The skb on CPU 1 has beed enqueued but no one
take it, until the next cpu pushing to the qdisc (if ever ...) will
notice and dequeue it.
This patch fix this by adding one explicit barrier. As spin_unlock() and
test_bit() ordering is a store-load ordering, a full memory barrier
smp_mb() is needed here.
Fixes: a90c57f2ce ("net: sched: fix packet stuck problem for lockless qdisc")
Signed-off-by: Guoju Fang <gjfang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220528101628.120193-1-gjfang@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In qdisc_run_begin(), smp_mb__before_atomic() used before test_bit()
does not provide any ordering guarantee as test_bit() is not an atomic
operation. This, added to the fact that the spin_trylock() call at
the beginning of qdisc_run_begin() does not guarantee acquire
semantics if it does not grab the lock, makes it possible for the
following statement :
if (test_bit(__QDISC_STATE_MISSED, &qdisc->state))
to be executed before an enqueue operation called before
qdisc_run_begin().
As a result the following race can happen :
CPU 1 CPU 2
qdisc_run_begin() qdisc_run_begin() /* true */
set(MISSED) .
/* returns false */ .
. /* sees MISSED = 1 */
. /* so qdisc not empty */
. __qdisc_run()
. .
. pfifo_fast_dequeue()
----> /* may be done here */ .
| . clear(MISSED)
| . .
| . smp_mb __after_atomic();
| . .
| . /* recheck the queue */
| . /* nothing => exit */
| enqueue(skb1)
| .
| qdisc_run_begin()
| .
| spin_trylock() /* fail */
| .
| smp_mb__before_atomic() /* not enough */
| .
---- if (test_bit(MISSED))
return false; /* exit */
In the above scenario, CPU 1 and CPU 2 both try to grab the
qdisc->seqlock at the same time. Only CPU 2 succeeds and enters the
bypass code path, where it emits its skb then calls __qdisc_run().
CPU1 fails, sets MISSED and goes down the traditionnal enqueue() +
dequeue() code path. But when executing qdisc_run_begin() for the
second time, after enqueuing its skbuff, it sees the MISSED bit still
set (by itself) and consequently chooses to exit early without setting
it again nor trying to grab the spinlock again.
Meanwhile CPU2 has seen MISSED = 1, cleared it, checked the queue
and found it empty, so it returned.
At the end of the sequence, we end up with skb1 enqueued in the
backlog, both CPUs out of __dev_xmit_skb(), the MISSED bit not set,
and no __netif_schedule() called made. skb1 will now linger in the
qdisc until somebody later performs a full __qdisc_run(). Associated
to the bypass capacity of the qdisc, and the ability of the TCP layer
to avoid resending packets which it knows are still in the qdisc, this
can lead to serious traffic "holes" in a TCP connection.
We fix this by replacing the smp_mb__before_atomic() / test_bit() /
set_bit() / smp_mb__after_atomic() sequence inside qdisc_run_begin()
by a single test_and_set_bit() call, which is more concise and
enforces the needed memory barriers.
Fixes: 89837eb4b2 ("net: sched: add barrier to ensure correct ordering for lockless qdisc")
Signed-off-by: Vincent Ray <vray@kalrayinc.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220526001746.2437669-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
commit 56b765b79e ("htb: improved accuracy at high rates") broke
"overhead X", "linklayer atm" and "mpu X" attributes.
"overhead X" and "linklayer atm" have already been fixed. This restores
the "mpu X" handling, as might be used by DOCSIS or Ethernet shaping:
tc class add ... htb rate X overhead 4 mpu 64
The code being fixed is used by htb, tbf and act_police. Cake has its
own mpu handling. qdisc_calculate_pkt_len still uses the size table
containing values adjusted for mpu by user space.
iproute2 tc has always passed mpu into the kernel via a tc_ratespec
structure, but the kernel never directly acted on it, merely stored it
so that it could be read back by `tc class show`.
Rather, tc would generate length-to-time tables that included the mpu
(and linklayer) in their construction, and the kernel used those tables.
Since v3.7, the tables were no longer used. Along with "mpu", this also
broke "overhead" and "linklayer" which were fixed in 01cb71d2d4
("net_sched: restore "overhead xxx" handling", v3.10) and 8a8e3d84b1
("net_sched: restore "linklayer atm" handling", v3.11).
"overhead" was fixed by simply restoring use of tc_ratespec::overhead -
this had originally been used by the kernel but was initially omitted
from the new non-table-based calculations.
"linklayer" had been handled in the table like "mpu", but the mode was
not originally passed in tc_ratespec. The new implementation was made to
handle it by getting new versions of tc to pass the mode in an extended
tc_ratespec, and for older versions of tc the table contents were analysed
at load time to deduce linklayer.
As "mpu" has always been given to the kernel in tc_ratespec,
accompanying the mpu-based table, we can restore system functionality
with no userspace change by making the kernel act on the tc_ratespec
value.
Fixes: 56b765b79e ("htb: improved accuracy at high rates")
Signed-off-by: Kevin Bracey <kevin@bracey.fi>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Vimalkumar <j.vimal@gmail.com>
Link: https://lore.kernel.org/r/20220112170210.1014351-1-kevin@bracey.fi
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
BPF layer extends the qdisc control block via struct bpf_skb_data_end
and because of that there is no more room to add variables to the
qdisc layer control block without going over the skb->cb size.
Extend the qdisc control block with a tc control block,
and move all tc related variables to there as a pre-step for
extending the tc control block with additional members.
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently rcu_barrier() is used to ensure that no readers of the
inactive mini_Qdisc buffer remain before it is reused. This waits for
any pending RCU callbacks to complete, when all that is actually
required is to wait for one RCU grace period to elapse after the buffer
was made inactive. This means that using rcu_barrier() may result in
unnecessary waits.
To improve this, store the current RCU state when a buffer is made
inactive and use poll_state_synchronize_rcu() to check whether a full
grace period has elapsed before reusing it. If a full grace period has
not elapsed, wait for a grace period to elapse, and in the non-RT case
use synchronize_rcu_expedited() to hasten it.
Since this approach eliminates the RCU callback it is no longer
necessary to synchronize_rcu() in the tp_head==NULL case. However, the
RCU state should still be saved for the previously active buffer.
Before this change I would typically see mini_qdisc_pair_swap() take
tens of milliseconds to complete. After this change it typcially
finishes in less than 1 ms, and often it takes just a few microseconds.
Thanks to Paul for walking me through the options for improving this.
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Seth Forshee <sforshee@digitalocean.com>
Link: https://lore.kernel.org/r/20211026130700.121189-1-seth@forshee.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
__QDISC_STATE_RUNNING is only set/cleared from contexts owning qdisc lock.
Thus we can use less expensive bit operations, as we were doing
before commit f9eb8aea2a ("net_sched: transform qdisc running bit into a seqcount")
Fixes: 29cbcd8582 ("net: sched: Remove Qdisc::running sequence counter")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ahmed S. Darwish <a.darwish@linutronix.de>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For non TCQ_F_NOLOCK qdisc, qdisc_run_begin() tries to set
__QDISC_STATE_RUNNING and should return true if the bit was not set.
test_and_set_bit() returns old bit value, therefore we need to invert.
Fixes: 29cbcd8582 ("net: sched: Remove Qdisc::running sequence counter")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ahmed S. Darwish <a.darwish@linutronix.de>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The Qdisc::running sequence counter has two uses:
1. Reliably reading qdisc's tc statistics while the qdisc is running
(a seqcount read/retry loop at gnet_stats_add_basic()).
2. As a flag, indicating whether the qdisc in question is running
(without any retry loops).
For the first usage, the Qdisc::running sequence counter write section,
qdisc_run_begin() => qdisc_run_end(), covers a much wider area than what
is actually needed: the raw qdisc's bstats update. A u64_stats sync
point was thus introduced (in previous commits) inside the bstats
structure itself. A local u64_stats write section is then started and
stopped for the bstats updates.
Use that u64_stats sync point mechanism for the bstats read/retry loop
at gnet_stats_add_basic().
For the second qdisc->running usage, a __QDISC_STATE_RUNNING bit flag,
accessed with atomic bitops, is sufficient. Using a bit flag instead of
a sequence counter at qdisc_run_begin/end() and qdisc_is_running() leads
to the SMP barriers implicitly added through raw_read_seqcount() and
write_seqcount_begin/end() getting removed. All call sites have been
surveyed though, and no required ordering was identified.
Now that the qdisc->running sequence counter is no longer used, remove
it.
Note, using u64_stats implies no sequence counter protection for 64-bit
architectures. This can lead to the qdisc tc statistics "packets" vs.
"bytes" values getting out of sync on rare occasions. The individual
values will still be valid.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The only factor differentiating per-CPU bstats data type (struct
gnet_stats_basic_cpu) from the packed non-per-CPU one (struct
gnet_stats_basic_packed) was a u64_stats sync point inside the former.
The two data types are now equivalent: earlier commits added a u64_stats
sync point to the latter.
Combine both data types into "struct gnet_stats_basic_sync". This
eliminates redundancy and simplifies the bstats read/write APIs.
Use u64_stats_t for bstats "packets" and "bytes" data types. On 64-bit
architectures, u64_stats sync points do not use sequence counter
protection.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The not-per-CPU variant of qdisc tc (traffic control) statistics,
Qdisc::gnet_stats_basic_packed bstats, is protected with Qdisc::running
sequence counter.
This sequence counter is used for reliably protecting bstats reads from
parallel writes. Meanwhile, the seqcount's write section covers a much
wider area than bstats update: qdisc_run_begin() => qdisc_run_end().
That read/write section asymmetry can lead to needless retries of the
read section. To prepare for removing the Qdisc::running sequence
counter altogether, introduce a u64_stats sync point inside bstats
instead.
Modify _bstats_update() to start/end the bstats u64_stats write
section.
For bisectability, and finer commits granularity, the bstats read
section is still protected with a Qdisc::running read/retry loop and
qdisc_run_begin/end() still starts/ends that seqcount write section.
Once all call sites are modified to use _bstats_update(), the
Qdisc::running seqcount will be removed and bstats read/retry loop will
be modified to utilize the internal u64_stats sync point.
Note, using u64_stats implies no sequence counter protection for 64-bit
architectures. This can lead to the statistics "packets" vs. "bytes"
values getting out of sync on rare occasions. The individual values will
still be valid.
[bigeasy: Minor commit message edits, init all gnet_stats_basic_packed.]
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The gnet_stats_queue::qlen member is only used in the SMP-case.
qdisc_qstats_qlen_backlog() needs to add qdisc_qlen() to qstats.qlen to
have the same value as that provided by qdisc_qlen_sum().
gnet_stats_copy_queue() needs to overwritte the resulting qstats.qlen
field whith the caller submitted qlen value. It might be differ from the
submitted value.
Let both functions use gnet_stats_add_queue() and remove unused
__gnet_stats_copy_queue().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The code for handling active queue changes is identical
between mq and mqprio, reuse it.
Suggested-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
mq / mqprio make the default child qdiscs visible. They only do
so for the qdiscs which are within real_num_tx_queues when the
device is registered. Depending on order of calls in the driver,
or if user space changes config via ethtool -L the number of
qdiscs visible under tc qdisc show will differ from the number
of queues. This is confusing to users and potentially to system
configuration scripts which try to make sure qdiscs have the
right parameters.
Add a new Qdisc_ops callback and make relevant qdiscs TTRT.
Note that this uncovers the "shortcut" created by
commit 1f27cde313 ("net: sched: use pfifo_fast for non real queues")
The default child qdiscs beyond initial real_num_tx are always
pfifo_fast, no matter what the sysfs setting is. Fixing this
gets a little tricky because we'd need to keep a reference
on whatever the default qdisc was at the time of creation.
In practice this is likely an non-issue the qdiscs likely have
to be configured to non-default settings, so whatever user space
is doing such configuration can replace the pfifos... now that
it will see them.
Reported-by: Matthew Massey <matthewmassey@fb.com>
Reviewed-by: Dave Taht <dave.taht@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
TC action ->init() API has 10 parameters, it becomes harder
to read. Some of them are just boolean and can be replaced
by flags. Similarly for the internal API tcf_action_init()
and tcf_exts_validate().
This patch converts them to flags and fold them into
the upper 16 bits of "flags", whose lower 16 bits are still
reserved for user-space. More specifically, the following
kernel flags are introduced:
TCA_ACT_FLAGS_POLICE replace 'name' in a few contexts, to
distinguish whether it is compatible with policer.
TCA_ACT_FLAGS_BIND replaces 'bind', to indicate whether
this action is bound to a filter.
TCA_ACT_FLAGS_REPLACE replaces 'ovr' in most contexts,
means we are replacing an existing action.
TCA_ACT_FLAGS_NO_RTNL replaces 'rtnl_held' but has the
opposite meaning, because we still hold RTNL in most
cases.
The only user-space flag TCA_ACT_FLAGS_NO_PERCPU_STATS is
untouched and still stored as before.
I have tested this patch with tdc and I do not see any
failure related to this patch.
Tested-by: Vlad Buslov <vladbu@nvidia.com>
Acked-by: Jamal Hadi Salim<jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Trivial conflict in net/netfilter/nf_tables_api.c.
Duplicate fix in tools/testing/selftests/net/devlink_port_split.py
- take the net-next version.
skmsg, and L4 bpf - keep the bpf code but remove the flags
and err params.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As MISSED and DRAINING state are used to indicate a non-empty
qdisc, qdisc->empty is not longer needed, so remove it.
Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # flexcan
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently pfifo_fast has both TCQ_F_CAN_BYPASS and TCQ_F_NOLOCK
flag set, but queue discipline by-pass does not work for lockless
qdisc because skb is always enqueued to qdisc even when the qdisc
is empty, see __dev_xmit_skb().
This patch calls sch_direct_xmit() to transmit the skb directly
to the driver for empty lockless qdisc, which aviod enqueuing
and dequeuing operation.
As qdisc->empty is not reliable to indicate a empty qdisc because
there is a time window between enqueuing and setting qdisc->empty.
So we use the MISSED state added in commit a90c57f2ce ("net:
sched: fix packet stuck problem for lockless qdisc"), which
indicate there is lock contention, suggesting that it is better
not to do the qdisc bypass in order to avoid packet out of order
problem.
In order to make MISSED state reliable to indicate a empty qdisc,
we need to ensure that testing and clearing of MISSED state is
within the protection of qdisc->seqlock, only setting MISSED state
can be done without the protection of qdisc->seqlock. A MISSED
state testing is added without the protection of qdisc->seqlock to
aviod doing unnecessary spin_trylock() for contention case.
As the enqueuing is not within the protection of qdisc->seqlock,
there is still a potential data race as mentioned by Jakub [1]:
thread1 thread2 thread3
qdisc_run_begin() # true
qdisc_run_begin(q)
set(MISSED)
pfifo_fast_dequeue
clear(MISSED)
# recheck the queue
qdisc_run_end()
enqueue skb1
qdisc empty # true
qdisc_run_begin() # true
sch_direct_xmit() # skb2
qdisc_run_begin()
set(MISSED)
When above happens, skb1 enqueued by thread2 is transmited after
skb2 is transmited by thread3 because MISSED state setting and
enqueuing is not under the qdisc->seqlock. If qdisc bypass is
disabled, skb1 has better chance to be transmited quicker than
skb2.
This patch does not take care of the above data race, because we
view this as similar as below:
Even at the same time CPU1 and CPU2 write the skb to two socket
which both heading to the same qdisc, there is no guarantee that
which skb will hit the qdisc first, because there is a lot of
factor like interrupt/softirq/cache miss/scheduling afffecting
that.
There are below cases that need special handling:
1. When MISSED state is cleared before another round of dequeuing
in pfifo_fast_dequeue(), and __qdisc_run() might not be able to
dequeue all skb in one round and call __netif_schedule(), which
might result in a non-empty qdisc without MISSED set. In order
to avoid this, the MISSED state is set for lockless qdisc and
__netif_schedule() will be called at the end of qdisc_run_end.
2. The MISSED state also need to be set for lockless qdisc instead
of calling __netif_schedule() directly when requeuing a skb for
a similar reason.
3. For netdev queue stopped case, the MISSED case need clearing
while the netdev queue is stopped, otherwise there may be
unnecessary __netif_schedule() calling. So a new DRAINING state
is added to indicate this case, which also indicate a non-empty
qdisc.
4. As there is already netif_xmit_frozen_or_stopped() checking in
dequeue_skb() and sch_direct_xmit(), which are both within the
protection of qdisc->seqlock, but the same checking in
__dev_xmit_skb() is without the protection, which might cause
empty indication of a lockless qdisc to be not reliable. So
remove the checking in __dev_xmit_skb(), and the checking in
the protection of qdisc->seqlock seems enough to avoid the cpu
consumption problem for netdev queue stopped case.
1. https://lkml.org/lkml/2021/5/29/215
Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # flexcan
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
qdisc->running seqcount operation is mainly used to do heuristic
locking on q->busylock for locked qdisc, see qdisc_is_running()
and __dev_xmit_skb().
So avoid doing seqcount operation for qdisc with TCQ_F_NOLOCK
flag.
Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # flexcan
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The spin_trylock() was assumed to contain the implicit
barrier needed to ensure the correct ordering between
STATE_MISSED setting/clearing and STATE_MISSED checking
in commit a90c57f2ce ("net: sched: fix packet stuck
problem for lockless qdisc").
But it turns out that spin_trylock() only has load-acquire
semantic, for strongly-ordered system(like x86), the compiler
barrier implicitly contained in spin_trylock() seems enough
to ensure the correct ordering. But for weakly-orderly system
(like arm64), the store-release semantic is needed to ensure
the correct ordering as clear_bit() and test_bit() is store
operation, see queued_spin_lock().
So add the explicit barrier to ensure the correct ordering
for the above case.
Fixes: a90c57f2ce ("net: sched: fix packet stuck problem for lockless qdisc")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Lockless qdisc has below concurrent problem:
cpu0 cpu1
. .
q->enqueue .
. .
qdisc_run_begin() .
. .
dequeue_skb() .
. .
sch_direct_xmit() .
. .
. q->enqueue
. qdisc_run_begin()
. return and do nothing
. .
qdisc_run_end() .
cpu1 enqueue a skb without calling __qdisc_run() because cpu0
has not released the lock yet and spin_trylock() return false
for cpu1 in qdisc_run_begin(), and cpu0 do not see the skb
enqueued by cpu1 when calling dequeue_skb() because cpu1 may
enqueue the skb after cpu0 calling dequeue_skb() and before
cpu0 calling qdisc_run_end().
Lockless qdisc has below another concurrent problem when
tx_action is involved:
cpu0(serving tx_action) cpu1 cpu2
. . .
. q->enqueue .
. qdisc_run_begin() .
. dequeue_skb() .
. . q->enqueue
. . .
. sch_direct_xmit() .
. . qdisc_run_begin()
. . return and do nothing
. . .
clear __QDISC_STATE_SCHED . .
qdisc_run_begin() . .
return and do nothing . .
. . .
. qdisc_run_end() .
This patch fixes the above data race by:
1. If the first spin_trylock() return false and STATE_MISSED is
not set, set STATE_MISSED and retry another spin_trylock() in
case other CPU may not see STATE_MISSED after it releases the
lock.
2. reschedule if STATE_MISSED is set after the lock is released
at the end of qdisc_run_end().
For tx_action case, STATE_MISSED is also set when cpu1 is at the
end if qdisc_run_end(), so tx_action will be rescheduled again
to dequeue the skb enqueued by cpu2.
Clear STATE_MISSED before retrying a dequeuing when dequeuing
returns NULL in order to reduce the overhead of the second
spin_trylock() and __netif_schedule() calling.
Also clear the STATE_MISSED before calling __netif_schedule()
at the end of qdisc_run_end() to avoid doing another round of
dequeuing in the pfifo_fast_dequeue().
The performance impact of this patch, tested using pktgen and
dummy netdev with pfifo_fast qdisc attached:
threads without+this_patch with+this_patch delta
1 2.61Mpps 2.60Mpps -0.3%
2 3.97Mpps 3.82Mpps -3.7%
4 5.62Mpps 5.59Mpps -0.5%
8 2.78Mpps 2.77Mpps -0.3%
16 2.22Mpps 2.22Mpps -0.0%
Fixes: 6b3ba9146f ("net: sched: allow qdiscs to handle locking")
Acked-by: Jakub Kicinski <kuba@kernel.org>
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow a policer action to enforce a rate-limit based on packets-per-second,
configurable using a packet-per-second rate and burst parameters.
e.g.
tc filter add dev tap1 parent ffff: u32 match \
u32 0 0 police pkts_rate 3000 pkts_burst 1000
Testing was unable to uncover a performance impact of this change on
existing features.
Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Louis Peens <louis.peens@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
