On Thu, Apr 30, 2020 at 5:40 AM Václav Zindulka <vaclav.zindu...@tlapnet.cz> wrote: > > On Wed, Apr 15, 2020 at 5:01 PM Václav Zindulka > <vaclav.zindu...@tlapnet.cz> wrote: > > > > > The problem is actually more complicated than I thought, although it > > > > > needs more work, below is the first pile of patches I have for you to > > > > > test: > > > > > > > > > > https://github.com/congwang/linux/commits/qdisc_reset > > > > > > > > > > It is based on the latest net-next branch. Please let me know the > > > > > result. > > > > > > > > I have applied all the patches in your four commits to my custom 5.4.6 > > > > kernel source. There was no change in the amount of fq_codel_reset > > > > calls. Tested on ifb, RJ45 and SFP+ interfaces. > > > > > > It is true my patches do not reduce the number of fq_codel_reset() calls, > > > they are intended to reduce the CPU time spent in each fq_codel_reset(). > > > > > > Can you measure this? Note, you do not have to add your own printk() > > > any more, because my patches add a few tracepoints, especially for > > > qdisc_reset(). So you can obtain the time by checking the timestamps > > > of these trace events. Of course, you can also use perf trace like you > > > did before. > > > > Sorry for delayed responses. We were moving to a new house so I didn't > > have much time to test it. I've measured your pile of patches applied > > vs unpatched kernel. Result is a little bit better, but it is only > > about 1s faster. Results are here. Do you need any additional reports > > or measurements of other interfaces? > > https://github.com/zvalcav/tc-kernel/tree/master/20200415 I've > > recompiled the kernel without printk which had some overhead too. > > Hello Cong, > > did you have any time to look at it further? I'm just asking since my > boss wants me to give him some verdict. I've started to study eBPF and > XDP in the meantime so we have an alternative in case there won't be a > solution to this problem.
Sorry for the delay. I lost connection to my dev machine, I am trying to setup this on my own laptop. Regarding to your test result above, I think I saw some difference on my side, I have no idea why you didn't see any difference. Please let me collect the data once I setup the test environment shortly today. Thanks!
