From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Eric Dumazet <edumazet@google.com>
Cc: bpf <bpf@vger.kernel.org>, netdev <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH net-next 3/4] net: dev: Makes sure netif_rx() can be invoked in any context.
Date: Thu, 3 Feb 2022 18:45:22 +0100 [thread overview]
Message-ID: <YfwUskgPuOREd9hs@linutronix.de> (raw)
In-Reply-To: <YfwGcHv6XQytcq68@linutronix.de>
On 2022-02-03 17:44:33 [+0100], To Eric Dumazet wrote:
> > I guess the cost of the local_bh_enable()/local_bh_disable() pair
> > will be roughly the same, please measure it :)
>
> We would avoid that branch maybe that helps. Will measure.
| BH OFF/ON : 722922586
| BH OFF/ON : 722931661
| BH OFF/ON : 725341486
| BH OFF/ON : 725909591
| BH OFF/ON : 741705606
| BH OFF/ON-OPT : 536683873
| BH OFF/ON-OPT : 536933779
| BH OFF/ON-OPT : 536967581
| BH OFF/ON-OPT : 537109700
| BH OFF/ON-OPT : 537148631
in a tight loop of 100000000 iterations:
BH OFF/ON = local_bh_disable(); local_bh_enable()
BH OFF/ON-OPT = local_bh_disable(); local_bh_enable_opt()
where local_bh_enable_opt() is the proposed function.
725341486 = ~7.3ns for one iteration.
536967581 = ~5.4ns for one iteration.
This is without tracing+lockdep. So I don't need to sell this to peterz
and focus one the previously suggested version.
Sebastian
next prev parent reply other threads:[~2022-02-03 17:45 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-02 12:28 [PATCH net-next 0/4] net: dev: PREEMPT_RT fixups Sebastian Andrzej Siewior
2022-02-02 12:28 ` [PATCH net-next 1/4] net: dev: Remove the preempt_disable() in netif_rx_internal() Sebastian Andrzej Siewior
2022-02-02 17:10 ` Eric Dumazet
2022-02-03 12:00 ` Toke Høiland-Jørgensen
2022-02-03 12:17 ` Sebastian Andrzej Siewior
2022-02-03 12:41 ` Toke Høiland-Jørgensen
2022-02-03 15:50 ` Sebastian Andrzej Siewior
2022-02-04 15:20 ` [PATCH net-next v2 1/4] net: dev: Remove preempt_disable() and get_cpu() " Sebastian Andrzej Siewior
2022-02-04 16:31 ` Jakub Kicinski
2022-02-04 16:42 ` Sebastian Andrzej Siewior
2022-02-04 16:32 ` Eric Dumazet
2022-02-03 12:16 ` [PATCH net-next 1/4] net: dev: Remove the preempt_disable() " Sebastian Andrzej Siewior
2022-02-02 12:28 ` [PATCH net-next 2/4] net: dev: Remove get_cpu() " Sebastian Andrzej Siewior
2022-02-02 17:14 ` Eric Dumazet
2022-02-03 12:14 ` Toke Høiland-Jørgensen
2022-02-02 12:28 ` [PATCH net-next 3/4] net: dev: Makes sure netif_rx() can be invoked in any context Sebastian Andrzej Siewior
2022-02-02 16:50 ` Jakub Kicinski
2022-02-03 12:20 ` Sebastian Andrzej Siewior
2022-02-03 19:38 ` Jakub Kicinski
2022-02-02 17:43 ` Eric Dumazet
2022-02-03 12:19 ` Toke Høiland-Jørgensen
2022-02-03 15:10 ` Sebastian Andrzej Siewior
2022-02-03 15:25 ` Eric Dumazet
2022-02-03 15:40 ` Sebastian Andrzej Siewior
2022-02-03 16:18 ` Eric Dumazet
2022-02-03 16:44 ` Sebastian Andrzej Siewior
2022-02-03 17:45 ` Sebastian Andrzej Siewior [this message]
2022-02-04 13:00 ` [PATCH net-next v2 " Sebastian Andrzej Siewior
2022-02-04 18:46 ` Eric Dumazet
2022-02-02 12:28 ` [PATCH net-next 4/4] net: dev: Make rps_lock() disable interrupts Sebastian Andrzej Siewior
2022-02-02 16:47 ` Jakub Kicinski
2022-02-03 16:41 ` [PATCH net-next v2 " Sebastian Andrzej Siewior
2022-02-03 19:39 ` Jakub Kicinski
2022-02-02 16:14 ` [PATCH net-next 0/4] net: dev: PREEMPT_RT fixups Jakub Kicinski
2022-02-03 11:59 ` Toke Høiland-Jørgensen
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