Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> Things got a lot more lively after that!
> 
> But most of the overhead seems to come from systemd trying to dump core or 
> something like that:
> 
>  85872 mingo     20   0   34712   3016   2656 S   4.6  0.0   0:00.14 systemd-coredum                                                                                                  
>  85440 mingo     20   0   34712   3028   2664 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85751 mingo     20   0   34712   3076   2716 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85840 mingo     20   0   34712   2988   2624 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85861 mingo     20   0   34712   3080   2720 S   4.2  0.0   0:00.13 systemd-coredum                                                                                                  
>  85954 mingo     20   0   34712   3028   2664 S   4.2  0.0   0:00.13 systemd-coredum          
> 
> and I have:
> 
>  fomalhaut:~/go/src/github.com/google/syzkaller> ulimit -c
>  0
> 
> weird ... Has any of you seen such behavior?

So the workaround for that is to disable systemd trying to log every core dump to 
the system journal (!), via:

  echo > /proc/sys/kernel/core_pattern 

Thanks,

	Ingo