From: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>
To: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"Karlsson, Magnus" <magnus.karlsson@intel.com>,
"Björn Töpel" <bjorn.topel@intel.com>,
Netdev <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
intel-wired-lan@lists.osuosl.org, "Fijalkowski,
Maciej" <maciej.fijalkowski@intel.com>,
"Herbert, Tom" <tom.herbert@intel.com>
Subject: Re: FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue
Date: Wed, 9 Oct 2019 09:53:21 -0700 [thread overview]
Message-ID: <2bc26acd-170d-634e-c066-71557b2b3e4f@intel.com> (raw)
In-Reply-To: <3ED8E928C4210A4289A677D2FEB48235140134CE@fmsmsx111.amr.corp.intel.com>
>> +
>> +u32 bpf_direct_xsk(const struct bpf_prog *prog, struct xdp_buff *xdp)
>> +{
>> + struct xdp_sock *xsk;
>> +
>> + xsk = xdp_get_xsk_from_qid(xdp->rxq->dev, xdp->rxq->queue_index);
>> + if (xsk) {
>> + struct bpf_redirect_info *ri =
>> + this_cpu_ptr(&bpf_redirect_info);
>> +
>> + ri->xsk = xsk;
>> + return XDP_REDIRECT;
>> + }
>> +
>> + return XDP_PASS;
>> +}
>> +EXPORT_SYMBOL(bpf_direct_xsk);
>
> So you're saying there is a:
> """
> xdpsock rxdrop 1 core (both app and queue's irq pinned to the same core)
> default : taskset -c 1 ./xdpsock -i enp66s0f0 -r -q 1
> direct-xsk :taskset -c 1 ./xdpsock -i enp66s0f0 -r -q 1 6.1x improvement in drop rate """
>
> 6.1x gain running above C code vs exactly equivalent BPF code?
> How is that possible?
It seems to be due to the overhead of __bpf_prog_run on older processors
(Ivybridge). The overhead is smaller on newer processors, but even on
skylake i see around 1.5x improvement.
perf report with default xdpsock
================================
Samples: 2K of event 'cycles:ppp', Event count (approx.): 8437658090
Overhead Command Shared Object Symbol
34.57% xdpsock xdpsock [.] main
17.19% ksoftirqd/1 [kernel.vmlinux] [k] ___bpf_prog_run
13.12% xdpsock [kernel.vmlinux] [k] ___bpf_prog_run
4.09% ksoftirqd/1 [kernel.vmlinux] [k] __x86_indirect_thunk_rax
3.08% xdpsock [kernel.vmlinux] [k] nmi
2.76% ksoftirqd/1 [kernel.vmlinux] [k] xsk_map_lookup_elem
2.33% xdpsock [kernel.vmlinux] [k] __x86_indirect_thunk_rax
2.33% ksoftirqd/1 [i40e] [k] i40e_clean_rx_irq_zc
2.16% xdpsock [kernel.vmlinux] [k] bpf_map_lookup_elem
1.82% ksoftirqd/1 [kernel.vmlinux] [k] xdp_do_redirect
1.41% ksoftirqd/1 [kernel.vmlinux] [k] xsk_rcv
1.39% ksoftirqd/1 [kernel.vmlinux] [k] update_curr
1.09% ksoftirqd/1 [kernel.vmlinux] [k] bpf_xdp_redirect_map
1.09% xdpsock [i40e] [k] i40e_clean_rx_irq_zc
1.08% ksoftirqd/1 [kernel.vmlinux] [k] __xsk_map_redirect
1.07% swapper [kernel.vmlinux] [k] xsk_umem_peek_addr
1.05% ksoftirqd/1 [kernel.vmlinux] [k] xsk_umem_peek_addr
0.89% swapper [kernel.vmlinux] [k] __xsk_map_redirect
0.87% ksoftirqd/1 [kernel.vmlinux] [k] __bpf_prog_run32
0.87% swapper [kernel.vmlinux] [k] intel_idle
0.67% xdpsock [kernel.vmlinux] [k] bpf_xdp_redirect_map
0.57% xdpsock [kernel.vmlinux] [k] xdp_do_redirect
perf report with direct xdpsock
===============================
Samples: 2K of event 'cycles:ppp', Event count (approx.): 17996091975
Overhead Command Shared Object Symbol
18.44% xdpsock [i40e] [k] i40e_clean_rx_irq_zc
15.14% ksoftirqd/1 [i40e] [k] i40e_clean_rx_irq_zc
6.87% xdpsock [kernel.vmlinux] [k] xsk_umem_peek_addr
5.03% ksoftirqd/1 [kernel.vmlinux] [k] xdp_do_redirect
4.21% xdpsock xdpsock [.] main
4.13% ksoftirqd/1 [i40e] [k]
i40e_clean_programming_status
3.71% xdpsock [kernel.vmlinux] [k] xsk_rcv
3.44% ksoftirqd/1 [kernel.vmlinux] [k] nmi
3.41% xdpsock [kernel.vmlinux] [k] nmi
3.20% ksoftirqd/1 [kernel.vmlinux] [k] xsk_rcv
2.45% xdpsock [kernel.vmlinux] [k] xdp_get_xsk_from_qid
2.35% ksoftirqd/1 [kernel.vmlinux] [k] xsk_umem_peek_addr
2.33% ksoftirqd/1 [kernel.vmlinux] [k] net_rx_action
2.16% ksoftirqd/1 [kernel.vmlinux] [k] xsk_umem_consume_tx
2.10% swapper [kernel.vmlinux] [k] __softirqentry_text_start
2.06% xdpsock [kernel.vmlinux] [k] native_irq_return_iret
1.43% xdpsock [kernel.vmlinux] [k] check_preempt_wakeup
1.42% xdpsock [kernel.vmlinux] [k] xsk_umem_consume_tx
1.22% xdpsock [kernel.vmlinux] [k] xdp_do_redirect
1.21% xdpsock [kernel.vmlinux] [k]
dma_direct_sync_single_for_device
1.16% ksoftirqd/1 [kernel.vmlinux] [k] irqtime_account_irq
1.09% xdpsock [kernel.vmlinux] [k] sock_def_readable
0.99% swapper [kernel.vmlinux] [k] intel_idle
0.88% xdpsock [i40e] [k]
i40e_clean_programming_status
0.74% ksoftirqd/1 [kernel.vmlinux] [k] xsk_umem_discard_addr
0.71% ksoftirqd/1 [kernel.vmlinux] [k] __switch_to
0.50% ksoftirqd/1 [kernel.vmlinux] [k]
dma_direct_sync_single_for_device
next prev parent reply other threads:[~2019-10-09 16:53 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-08 6:16 [PATCH bpf-next 0/4] Enable direct receive on AF_XDP sockets Sridhar Samudrala
2019-10-08 6:16 ` [PATCH bpf-next 1/4] bpf: introduce bpf_get_prog_id and bpf_set_prog_id helper functions Sridhar Samudrala
2019-10-08 6:16 ` [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue Sridhar Samudrala
2019-10-08 6:58 ` Toke Høiland-Jørgensen
2019-10-08 8:47 ` Björn Töpel
2019-10-08 8:48 ` Björn Töpel
2019-10-08 9:04 ` Toke Høiland-Jørgensen
2019-10-08 8:05 ` Björn Töpel
2019-10-09 16:32 ` Samudrala, Sridhar
2019-10-09 1:20 ` Alexei Starovoitov
[not found] ` <3ED8E928C4210A4289A677D2FEB48235140134CE@fmsmsx111.amr.corp.intel.com>
2019-10-09 16:53 ` Samudrala, Sridhar [this message]
2019-10-09 17:17 ` FW: " Alexei Starovoitov
2019-10-09 19:12 ` Samudrala, Sridhar
2019-10-10 1:06 ` Alexei Starovoitov
2019-10-18 18:40 ` Samudrala, Sridhar
2019-10-18 19:22 ` Toke Høiland-Jørgensen
2019-10-19 0:14 ` Alexei Starovoitov
2019-10-19 0:45 ` Samudrala, Sridhar
2019-10-19 2:25 ` Alexei Starovoitov
2019-10-20 10:14 ` Toke Høiland-Jørgensen
2019-10-20 17:12 ` [Intel-wired-lan] " Björn Töpel
2019-10-21 20:10 ` Samudrala, Sridhar
2019-10-21 22:34 ` Alexei Starovoitov
2019-10-22 19:06 ` Samudrala, Sridhar
2019-10-23 17:42 ` Alexei Starovoitov
2019-10-24 18:12 ` Samudrala, Sridhar
2019-10-25 7:42 ` Björn Töpel
2019-10-31 22:38 ` Samudrala, Sridhar
2019-10-31 23:15 ` Alexei Starovoitov
2019-11-01 0:21 ` Jakub Kicinski
2019-11-01 18:31 ` Samudrala, Sridhar
2019-11-04 2:08 ` dan
2019-10-25 9:07 ` Björn Töpel
2019-10-08 6:16 ` [PATCH bpf-next 3/4] libbpf: handle AF_XDP sockets created with XDP_DIRECT bind flag Sridhar Samudrala
2019-10-08 8:05 ` Björn Töpel
2019-10-08 6:16 ` [PATCH bpf-next 4/4] xdpsock: add an option to create AF_XDP sockets in XDP_DIRECT mode Sridhar Samudrala
2019-10-08 8:05 ` Björn Töpel
2019-10-08 8:05 ` [PATCH bpf-next 0/4] Enable direct receive on AF_XDP sockets Björn Töpel
2019-10-09 16:19 ` Samudrala, Sridhar
2019-10-09 0:49 ` Jakub Kicinski
2019-10-09 6:29 ` Samudrala, Sridhar
2019-10-09 16:53 ` Jakub Kicinski
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