Re: [PATCH 1/1] test/pmd_perf: handling of unknown connection speed

[Thomas Monjalon <thomas@monjalon.net>]

11/05/2022 18:33, Heinrich Schuchardt:
> When running DPDK in QEMU it cannot determine the connection speed.
> pmd_perf_autotest treats this as if the connection speed where
> UNIT32_MAX Mbps:
> 
>     RTE>>pmd_perf_autotest
>     Start PMD RXTX cycles cost test.
>     Allocated mbuf pool on socket 0
>     CONFIG RXD=1024 TXD=1024
>     Performance test runs on lcore 1 socket 0
>     Port 0 Address:52:54:00:12:34:57
>     Port 1 Address:52:54:00:12:34:58
>     Checking link statuses...
>     Port 0 Link up at Unknown FDX Autoneg
>     Port 1 Link up at Unknown FDX Autoneg
>     IPv4 pktlen 46
>     UDP pktlen 26
>     Generate 4096 packets @socket 0
>     inject 2048 packet to port 0
>     inject 2048 packet to port 1
>     Total packets inject to prime ports = 4096
>     Each port will do 6391320379464 packets per second
>     Test will stop after at least 25565281517856 packets received
> 
> This will not allow the test to terminate in a reasonable timespan.
> Just assume 10 Gbps in this case instead:
> 
>     ...
>     Test will stop after at least 59523808 packets received
> 
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  app/test/test_pmd_perf.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/app/test/test_pmd_perf.c b/app/test/test_pmd_perf.c
> index 25611bfe9b..ee08c8aade 100644
> --- a/app/test/test_pmd_perf.c
> +++ b/app/test/test_pmd_perf.c
> @@ -486,10 +486,17 @@ main_loop(__rte_unused void *args)
>  	}
>  	printf("Total packets inject to prime ports = %u\n", idx);
>  
> -	packets_per_second = (link_mbps * 1000 * 1000) /
> -		((PACKET_SIZE + FRAME_GAP + MAC_PREAMBLE) * CHAR_BIT);
> -	printf("Each port will do %"PRIu64" packets per second\n",
> -	       packets_per_second);
> +	if (link_mbps != RTE_ETH_SPEED_NUM_UNKNOWN) {
> +		packets_per_second = (link_mbps * 1000 * 1000) /
> +			((PACKET_SIZE + FRAME_GAP + MAC_PREAMBLE) * CHAR_BIT);
> +		printf("Each port will do %"PRIu64" packets per second\n",
> +		       packets_per_second);
> +		total_packets = RTE_TEST_DURATION * conf->nb_ports * packets_per_second;

This is redundant with below.

> +	} else {
> +		/* We don't know the speed. Pretend it is 10G */
> +		packets_per_second = ((uint64_t)RTE_ETH_SPEED_NUM_10G * 1000 * 1000) /
> +			((PACKET_SIZE + FRAME_GAP + MAC_PREAMBLE) * CHAR_BIT);
> +	}
>  
>  	total_packets = RTE_TEST_DURATION * conf->nb_ports * packets_per_second;

Why not just inserting this:

if (link_mbps == RTE_ETH_SPEED_NUM_UNKNOWN)
	link_mbps = RTE_ETH_SPEED_NUM_10G;