On 11/3/2022 2:20 PM, mike tancsa wrote:
Yes, I think 4 queues are enough for 10G.
Sadly, no luck. Still about the same rate of overflows :(
FYI, I worked around the issue by using two 520-CR NICs instead of the
one 540-CR NIC and performance is solid again with no dropped packets
Another configuration point on this. Moving to RELENG_13 has some
different defaults with respect to power/performance ratios for my
motherboard and CPU (SuperMicro X11SCH-F, Xeon(R) E-2226G). On
RELENG_13, the hwpstate_intel attaches by default and is used to scale
up and down the CPU frequency. I am guessing due to the somewhat bursty
nature of the load, the CPU scaling down to 800Hz could not scale back
up fast enough to deal with a sudden burst of traffic going from say
300Mb/s to 800Mb/s and some packets would overflow the NIC's buffers.
Printing out the cpu frequency once per second, it would be constantly
floating up and down from 900 to 4300. At first, I couldnt quite get my
head around the fact that the most lost packets would happen at the
lowest pps periods. Once I started to graph the cpu freq, CPU temp,
pps, Mb/s, the pattern really stood out. Sure enough, setting
dev.hwpstate_intel.0.epp=0 on the cores from the default of 50 (see
HWPSTATE_INTEL(4) ) made the difference.
# sysctl -a dev.cpufreq.0.freq_driver
dev.cpufreq.0.freq_driver: hwpstate_intel0
#
---Mike
