Re: Performance test for CUBIC in stable/14

Here is my example. I am using two 6-core/12-threads desktops for my bhyve
servers.
CPU: AMD Ryzen 5 5560U with Radeon Graphics          (2295.75-MHz K8-class
CPU)

You can find test results on VMs from my wiki:
https://wiki.freebsd.org/chengcui/testD46046

All the CPU utilization results are low, especially for these throughput
over 900 Mb/s.

cc

On Wed, Oct 23, 2024 at 5:43 PM void <void@f-m.fm> wrote:

> On Wed, Oct 23, 2024 at 03:14:08PM -0400, Cheng Cui wrote:
> >I see. The result of `newreno` vs. `cubic` shows non-constant/infrequent
> >packet
> >retransmission. So TCP congestion control has little impact on improving
> the
> >performance.
> >
> >The performance bottleneck may come from somewhere else. For example, the
> >sender CPU shows 97.7% utilization. Would there be any way to reduce CPU
> >usage?
>
> There are 11 VMs running on the bhyve server. None of them are very busy
> but the
> server shows
> % uptime
>   9:54p.m.  up 8 days,  6:08, 22 users, load averages: 0.82, 1.25, 1.74
>
> The test vm vm4-fbsd14s:
> % uptime
>   9:55PM  up 2 days,  3:12, 5 users, load averages: 0.35, 0.31, 0.21
>
> It has
> % sysctl hw.ncpu
> hw.ncpu: 8
>
> and
> avail memory = 66843062272 (63746 MB)
>
> so it's not short of resources.
>
> A test just now gave these results:
> - - - - - - - - - - - - - - - - - - - - - - - - -
> Test Complete. Summary Results:
> [ ID] Interval           Transfer     Bitrate         Retr
> [  5]   0.00-20.04  sec  1.31 GBytes   563 Mbits/sec    0
>  sender
> [  5]   0.00-20.06  sec  1.31 GBytes   563 Mbits/sec
> receiver
> CPU Utilization: local/sender 94.1% (0.1%u/94.1%s), remote/receiver 15.5%
> (1.5%u/13.9%s)
> snd_tcp_congestion cubic
> rcv_tcp_congestion cubic
>
> iperf Done.
>
> so I'm not sure how the utilization figure was synthesised, unless it's
> derived
> from something like 'top' where 1.00 is 100%. Load when running the test
> got to
> 0.83 as observed in 'top' in another terminal. Five mins after the test,
> load in the vm is: 0.32, 0.31, 0.26
> on the bhyve host: 0.39, 0.61, 1.11
>
> Before we began testing, I was looking at the speed issue as being caused
> by
> something to do with interrupts and/or polling, and/or HZ, somehting that
> linux
> handles differently and gives better results on the same bhyve host.
> Maybe rebuilding the kernel with a different scheduler on both the host
> and the
> freebsd vms will give a better result for freebsd if tweaking sysctls
> doesn't
> make much of a difference.
>
> In terms of real-world bandwidth, I found that the combination of your
> modified
> cc_cubic + rack gave the best results in terms of overall throughput in a
> speedtest context, although it's slower to get to its max throughput than
> cubic
> alone. I'm still testing with a webdav/rsync context (cubic against
> cubic+rack)
>
> The next lot of testing after changing the scheduler will be on a KVM
> host,
> with various *BSDs as guests.
>
> There may be a tradeoff of stability against speed I guess.
> --
>
>

-- 
Best Regards,
Cheng Cui