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Date: Fri, 01 Mar 2024 09:23:57 -0800
From: John Fastabend <john.fastabend@gmail.com>
To: Song Yoong Siang <yoong.siang.song@intel.com>, 
 Jesse Brandeburg <jesse.brandeburg@intel.com>, 
 Tony Nguyen <anthony.l.nguyen@intel.com>, 
 "David S . Miller" <davem@davemloft.net>, 
 Eric Dumazet <edumazet@google.com>, 
 Jakub Kicinski <kuba@kernel.org>, 
 Paolo Abeni <pabeni@redhat.com>, 
 Richard Cochran <richardcochran@gmail.com>, 
 Alexei Starovoitov <ast@kernel.org>, 
 Daniel Borkmann <daniel@iogearbox.net>, 
 Jesper Dangaard Brouer <hawk@kernel.org>, 
 John Fastabend <john.fastabend@gmail.com>, 
 Stanislav Fomichev <sdf@google.com>, 
 Vinicius Costa Gomes <vinicius.gomes@intel.com>, 
 Florian Bezdeka <florian.bezdeka@siemens.com>, 
 Andrii Nakryiko <andrii@kernel.org>, 
 Eduard Zingerman <eddyz87@gmail.com>, 
 Mykola Lysenko <mykolal@fb.com>, 
 Martin KaFai Lau <martin.lau@linux.dev>, 
 Song Liu <song@kernel.org>, 
 Yonghong Song <yonghong.song@linux.dev>, 
 KP Singh <kpsingh@kernel.org>, 
 Hao Luo <haoluo@google.com>, 
 Jiri Olsa <jolsa@kernel.org>, 
 Shuah Khan <shuah@kernel.org>
Cc: intel-wired-lan@lists.osuosl.org, 
 netdev@vger.kernel.org, 
 linux-kernel@vger.kernel.org, 
 bpf@vger.kernel.org, 
 linux-kselftest@vger.kernel.org, 
 xdp-hints@xdp-project.net
Message-ID: <65e20f2d314bd_5dcfe20857@john.notmuch>
In-Reply-To: <20240301162348.898619-2-yoong.siang.song@intel.com>
References: <20240301162348.898619-1-yoong.siang.song@intel.com>
 <20240301162348.898619-2-yoong.siang.song@intel.com>
Subject: RE: [PATCH iwl-next,v2 1/2] selftests/bpf: xdp_hw_metadata reduce
 sleep interval
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Song Yoong Siang wrote:
> In current ping-pong design, xdp_hw_metadata will wait until the packet
> transmition completely done, then only start to receive the next packet.
> 
> The current sleep interval is 10ms, which is unnecessary large. Typically,
> a NIC does not need such a long time to transmit a packet. Furthermore,
> during this 10ms sleep time, the app is unable to receive incoming packets.
> 
> Therefore, this commit reduce sleep interval to 10us, so that
> xdp_hw_metadata able to support periodic packets with shorter interval.
> 10us * 500 = 5ms should be enough for packet transmission and status
> retrival.
> 
> Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
> ---
>  tools/testing/selftests/bpf/xdp_hw_metadata.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> index 878d68db0325..bdf5d8180067 100644
> --- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
> +++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> @@ -480,7 +480,7 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
>  					for (int j = 0; j < 500; j++) {
>  						if (complete_tx(xsk, clock_id))
>  							break;
> -						usleep(10*1000);
> +						usleep(10);
>  					}
>  				}
>  			}
> -- 
> 2.34.1
> 

Acked-by: John Fastabend <john.fastabend@gmail.com>