On 03/26/2018 02:16 PM, Tal Gilboa wrote: > On 3/23/2018 4:19 AM, Florian Fainelli wrote: >> Hi all, >> >> This patch series adds adaptive interrupt coalescing for the Gigabit >> Ethernet >> drivers SYSTEMPORT and GENET. >> >> This really helps lower the interrupt count and system load, as >> measured by >> vmstat for a Gigabit TCP RX session: > > I don't see an improvement in system load, the opposite - 42% vs. 100% > for SYSTEMPORT and 85% vs. 100% for GENET. Both with the same bandwidth.
Looks like I did not extract the correct data the load could spike in both cases (with and without net_dim) up to 100, but averaged over the transmission I see the following: GENET without: 1 0 0 1169568 0 25556 0 0 0 0 130079 62795 2 86 13 0 0 GENET with: 1 0 0 1169536 0 25556 0 0 0 0 10566 10869 1 21 78 0 0 > Am I missing something? Talking about bandwidth, I would expect 941Mb/s > (assuming this is TCP over IPv4). Do you know why the reduced interrupt > rate doesn't improve bandwidth? I am assuming that this comes down to a latency, still capturing some pcap files to analyze the TCP session with wireshark and see if that is indeed what is going on. The test machine is actually not that great > Also, any effect on the client side (you > mentioned enabling TX moderation for SYSTEMPORT)? Yes, on SYSTEMPORT, being the TCP IPv4 client, I have the following: SYSTEMPORT without: 2 0 0 191428 0 25748 0 0 0 0 86254 264 0 41 59 0 0 SYSTEMPORT with: 3 0 0 190176 0 25748 0 0 0 0 45485 31332 0 100 0 0 0 I don't get top to agree with these load results though but it looks like we just have the CPU spinning more, does not look like a win. Thanks a lot for taking a look at this Tal! -- Florian
