Subject: Re: [PATCH net-next v1 1/6] lan743x: boost performance on cpu archs w/o dma cache snooping

From: Sergej Bauer <[email-masked]>
Date: Fri, 5 Feb 2021 15:44:19 +0300

Hi Sven
I can confirm great stability improvement after your patch
"lan743x: boost performance on cpu archs w/o dma cache snooping".
Please note, that test_ber opens raw sockets as
s = socket(AF_PACKET, SOCK_RAW, ETH_P_ALL)
and resulting 'average speed' is a average egress speed.

Test machine is Intel Pentium G4560 3.50GHz
lan743x with rejected virtual phy 'inside'

What I had before:
$ ifmtu eth7 500
$ test_ber -l eth7 -c 1000 -n 1000000 -f500 --no-conf
...
number of sent packets      = 1000000
number of received packets  = 289017
number of lost packets = 710983
number of out of order packets = 0
number of bit errors   = 0
total errors detected  = 710983
bit error rate         = 0.710983
average speed: 429.3799 Mbit/s

$ ifmtu eth7 1500
$ sudo test_ber -l eth7 -c 1000 -n 1000000 -f1500 --no-conf
...
number of sent packets      = 1000000
number of received packets  = 577194
number of lost packets = 422806
number of out of order packets = 0
number of bit errors   = 0
total errors detected  = 422806
bit error rate         = 0.422806
average speed: 644.6557 Mbit/s
---

and what I had after your patch:
$ ifmtu eth7 500
$ test_ber -l eth7 -c 1000 -n 1000000 -f500 --no-conf
...
number of sent packets      = 1000000
number of received packets  = 711329
number of lost packets = 288671
number of out of order packets = 0
number of bit errors   = 0
total errors detected  = 288671
bit error rate         = 0.288671
average speed: 429.2263 Mbit/s

$ ifmtu eth7 1500
$ test_ber -l eth7 -c 1000 -n 1000000 -f1500 --no-conf
...
number of sent packets      = 1000000
number of received packets  = 1000000
number of lost packets = 0
number of out of order packets = 0
number of bit errors   = 0
total errors detected  = 0
bit error rate         = 0
average speed: 644.5405 Mbit/s