On 2014/11/01 15:31, Federico Giannici wrote: > > > >This is expected if you increase HZ without changing how livelock > >detection works. It sets a timer every clock tick, when that timer has > >triggered it checks how many ticks elapsed, if >1 livelock is detected. > >This triggers livelock avoidance which will slow down your network > >traffic so yes you do want to pay attention to them. sys/net/if.c > > Thank you for your reply. > Unfortunately I haven't enough expertise in kernel programming to really > understand where is the problem. > However, are you saying that the kernel doesn't correctly handle the case > where HZ != 100? > So, is this a kernel bug?
In my opinion, no - if somebody modifies the kernel (including by changing the config), it's up to them to work out the implications of that change and make other adjustments that may be necessary. Expertise isn't needed but testing and experimentation is. > >Also note, if you're graphing by calling sysctl(8) that may be locking > >the kernel for long enough to trigger livelock detection! > > I read the sysctl value only once per five minutes, so this is not a > problem. That's OK then (just wanted to mention it as I noticed it on my home adsl router where I've been experimenting with HZ changes).
