From: John Fastabend <john.fastabend@gmail.com>
To: Magnus Karlsson <magnus.karlsson@gmail.com>,
magnus.karlsson@intel.com, bjorn.topel@intel.com, ast@kernel.org,
daniel@iogearbox.net, netdev@vger.kernel.org,
jonathan.lemon@gmail.com
Cc: maciejromanfijalkowski@gmail.com,
intel-wired-lan@lists.osuosl.org, bpf@vger.kernel.org
Subject: RE: [Intel-wired-lan] [PATCH bpf-next 4/6] xsk: introduce padding between more ring pointers
Date: Mon, 09 Nov 2020 12:43:43 -0800 [thread overview]
Message-ID: <5fa9a9ffc2ea3_8c0e208a2@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <1604498942-24274-5-git-send-email-magnus.karlsson@gmail.com>
Magnus Karlsson wrote:
> From: Magnus Karlsson <magnus.karlsson@intel.com>
>
> Introduce one cache line worth of padding between the consumer pointer
> and the flags field as well as between the flags field and the start
> of the descriptors in all the lockless rings. This so that the x86 HW
> adjacency prefetcher will not prefetch the adjacent pointer/field when
> only one pointer/field is going to be used. This improves throughput
> performance for the l2fwd sample app with 1% on my machine with HW
> prefetching turned on in the BIOS.
>
> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
> ---
Acked-by: John Fastabend <john.fastabend@gmail.com>
> net/xdp/xsk_queue.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index cdb9cf3..74fac80 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -18,9 +18,11 @@ struct xdp_ring {
> /* Hinder the adjacent cache prefetcher to prefetch the consumer
> * pointer if the producer pointer is touched and vice versa.
> */
> - u32 pad ____cacheline_aligned_in_smp;
> + u32 pad1 ____cacheline_aligned_in_smp;
> u32 consumer ____cacheline_aligned_in_smp;
> + u32 pad2 ____cacheline_aligned_in_smp;
> u32 flags;
> + u32 pad3 ____cacheline_aligned_in_smp;
> };
>
> /* Used for the RX and TX queues for packets */
> --
> 2.7.4
>
> _______________________________________________
> Intel-wired-lan mailing list
> Intel-wired-lan@osuosl.org
> https://lists.osuosl.org/mailman/listinfo/intel-wired-lan
next prev parent reply other threads:[~2020-11-09 20:43 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 14:08 [PATCH bpf-next 0/6] xsk: i40e: Tx performance improvements Magnus Karlsson
2020-11-04 14:08 ` [PATCH bpf-next 1/6] i40e: introduce lazy Tx completions for AF_XDP zero-copy Magnus Karlsson
2020-11-04 23:33 ` Jakub Kicinski
2020-11-04 23:35 ` Jakub Kicinski
2020-11-05 14:17 ` Magnus Karlsson
2020-11-05 15:45 ` Jakub Kicinski
2020-11-06 19:09 ` Magnus Karlsson
2020-11-04 14:08 ` [PATCH bpf-next 2/6] samples/bpf: increment Tx stats at sending Magnus Karlsson
2020-11-09 20:47 ` [Intel-wired-lan] " John Fastabend
2020-11-10 7:12 ` Magnus Karlsson
2020-11-04 14:08 ` [PATCH bpf-next 3/6] i40e: remove unnecessary sw_ring access from xsk Tx Magnus Karlsson
2020-11-09 20:48 ` [Intel-wired-lan] " John Fastabend
2020-11-04 14:09 ` [PATCH bpf-next 4/6] xsk: introduce padding between more ring pointers Magnus Karlsson
2020-11-09 20:43 ` John Fastabend [this message]
2020-11-04 14:09 ` [PATCH bpf-next 5/6] xsk: introduce batched Tx descriptor interfaces Magnus Karlsson
2020-11-09 21:06 ` [Intel-wired-lan] " John Fastabend
2020-11-10 8:28 ` Magnus Karlsson
2020-11-04 14:09 ` [PATCH bpf-next 6/6] i40e: use batched xsk Tx interfaces to increase performance Magnus Karlsson
2020-11-04 23:01 ` Maciej Fijalkowski
2020-11-05 7:19 ` Magnus Karlsson
2020-11-09 21:10 ` [Intel-wired-lan] " John Fastabend
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