From: John Fastabend <john.fastabend@gmail•com>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: xiyou.wangcong@gmail•com, jhs@mojatatu•com,
alexei.starovoitov@gmail•com, brouer@redhat•com,
john.r.fastabend@intel•com, netdev@vger•kernel.org,
davem@davemloft•net
Subject: Re: [RFC PATCH 01/13] net: sched: allow qdiscs to handle locking
Date: Wed, 17 Aug 2016 15:49:19 -0700 [thread overview]
Message-ID: <57B4E9EF.5070400@gmail.com> (raw)
In-Reply-To: <1471473180.29842.44.camel@edumazet-glaptop3.roam.corp.google.com>
On 16-08-17 03:33 PM, Eric Dumazet wrote:
> On Wed, 2016-08-17 at 12:33 -0700, John Fastabend wrote:
>> This patch adds a flag for queueing disciplines to indicate the stack
>> does not need to use the qdisc lock to protect operations. This can
>> be used to build lockless scheduling algorithms and improving
>> performance.
>>
>> The flag is checked in the tx path and the qdisc lock is only taken
>> if it is not set. For now use a conditional if statement. Later we
>> could be more aggressive if it proves worthwhile and use a static key
>> or wrap this in a likely().
>>
>> Signed-off-by: John Fastabend <john.r.fastabend@intel•com>
>> ---
>> include/net/pkt_sched.h | 4 +++-
>> include/net/sch_generic.h | 1 +
>> net/core/dev.c | 32 ++++++++++++++++++++++++++++----
>> net/sched/sch_generic.c | 26 ++++++++++++++++----------
>> 4 files changed, 48 insertions(+), 15 deletions(-)
>>
>> diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
>> index 7caa99b..69540c6 100644
>> --- a/include/net/pkt_sched.h
>> +++ b/include/net/pkt_sched.h
>> @@ -107,8 +107,10 @@ void __qdisc_run(struct Qdisc *q);
>>
>> static inline void qdisc_run(struct Qdisc *q)
>> {
>> - if (qdisc_run_begin(q))
>> + if (qdisc_run_begin(q)) {
>> __qdisc_run(q);
>> + qdisc_run_end(q);
>> + }
>> }
>
>
> Looks like you could have a separate patch, removing qdisc_run_end()
> call done in __qdisc_run(q) ?
>
> Then the 'allow qdiscs to handle locking'
>
>
Agreed that would clean this up a bit. Will do for next rev.
next prev parent reply other threads:[~2016-08-17 22:49 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 19:33 [RFC PATCH 00/13] Series short description John Fastabend
2016-08-17 19:33 ` [RFC PATCH 01/13] net: sched: allow qdiscs to handle locking John Fastabend
2016-08-17 22:33 ` Eric Dumazet
2016-08-17 22:49 ` John Fastabend [this message]
2016-08-17 22:34 ` Eric Dumazet
2016-08-17 22:48 ` John Fastabend
2016-08-17 19:34 ` [RFC PATCH 02/13] net: sched: qdisc_qlen for per cpu logic John Fastabend
2016-08-17 19:34 ` [RFC PATCH 03/13] net: sched: provide per cpu qstat helpers John Fastabend
2016-08-17 19:35 ` [RFC PATCH 04/13] net: sched: provide atomic qlen helpers for bypass case John Fastabend
2016-08-17 19:35 ` [RFC PATCH 05/13] net: sched: a dflt qdisc may be used with per cpu stats John Fastabend
2016-08-17 19:35 ` [RFC PATCH 06/13] net: sched: per cpu gso handlers John Fastabend
2016-08-17 19:36 ` [RFC PATCH 07/13] net: sched: support qdisc_reset on NOLOCK qdisc John Fastabend
2016-08-17 22:53 ` Eric Dumazet
2016-08-17 22:59 ` John Fastabend
2016-08-17 19:36 ` [RFC PATCH 08/13] net: sched: support skb_bad_tx with lockless qdisc John Fastabend
2016-08-17 22:58 ` Eric Dumazet
2016-08-17 23:00 ` John Fastabend
2016-08-23 20:11 ` John Fastabend
2016-08-17 19:37 ` [RFC PATCH 09/13] net: sched: helper to sum qlen John Fastabend
2016-08-17 19:37 ` [RFC PATCH 10/13] net: sched: lockless support for netif_schedule John Fastabend
2016-08-17 19:46 ` John Fastabend
2016-08-17 23:01 ` Eric Dumazet
2016-08-17 23:17 ` John Fastabend
2016-08-17 23:33 ` Eric Dumazet
2016-08-17 19:38 ` [RFC PATCH 11/13] net: sched: pfifo_fast use alf_queue John Fastabend
2016-08-19 10:13 ` Jesper Dangaard Brouer
2016-08-19 15:44 ` John Fastabend
2016-08-17 19:38 ` [RFC PATCH 12/13] net: sched: add support for TCQ_F_NOLOCK subqueues to sch_mq John Fastabend
2016-08-17 19:49 ` John Fastabend
2016-08-17 23:04 ` Eric Dumazet
2016-08-17 23:18 ` John Fastabend
2016-08-17 19:39 ` [RFC PATCH 13/13] net: sched: add support for TCQ_F_NOLOCK subqueues to sch_mqprio John Fastabend
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