Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1353276

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

From Ingo Molnar <mingo@kernel.org>
Newsgroups linux.kernel
Subject Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer
Date 2016-03-08 19:10 +0100
Message-ID <raueZ-4va-3@gated-at.bofh.it> (permalink)
References (5 earlier) <ratCj-3TL-29@gated-at.bofh.it> <ratLZ-40W-37@gated-at.bofh.it> <ratVF-47w-21@gated-at.bofh.it> <ratVI-47w-79@gated-at.bofh.it> <rau5k-4bI-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


* Ingo Molnar <mingo@kernel.org> wrote:

> 
> * Ingo Molnar <mingo@kernel.org> 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 

So with that fixed, I finally started fuzzing for real.

With nproc set to 120 it seems to be chugging along at about 25% system 
utilization:

Tasks: 1271 total,   1 running, 1270 sleeping,   0 stopped,   0 zombie
%Cpu(s):  4.5 us, 35.3 sy,  0.0 ni, 55.2 id,  0.5 wa,  4.5 hi,  0.0 si,  0.0 st
KiB Mem : 26401230+total, 25401017+free,  1624640 used,  8377496 buff/cache
KiB Swap:        0 total,        0 free,        0 used. 26143329+avail Mem 

   PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                                                                                          
 87593 mingo     20   0 7850436 162284  11672 S  2941  0.1  33:01.83 syz-fuzzer                                                                                                       
   923 root      20   0   84772  44344  43840 S  22.8  0.0   1:23.86 systemd-journal                                                                                                  
  1369 root      16  -4  114636   3256   2832 S  15.7  0.0   0:29.03 auditd                                                                                                           
  1379 root      12  -8   80236   1764   1432 S   8.3  0.0   0:15.79 audispd                                                                                                          
   878 root      20   0       0      0      0 S   6.9  0.0   0:16.55 jbd2/sda1-8                                                                                                      
  1381 root      16  -4   52216   3232   2892 S   3.8  0.0   0:07.08 sedispatch              

Even that one is not ideal - obviously there's way too much systemd-journal 
overhead, but I'm unable to turn the darn thing off ...

with nproc=480 it does not seem to be working very well - it quickly generates:

2016/03/08 18:59:38 local-0: lost connection: exit status 2
2016/03/08 18:59:38 local-0: saving crash 'lost connection' to crash-local-0-1457459978295423413

and then after some time starts to ramp up again. It's mostly idling around.

Thanks,

	Ingo

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[RESEND PATCH 0/5] perf core: Support overwrite ring buffer Wang Nan <wangnan0@huawei.com> - 2016-03-07 05:00 +0100
  [RESEND PATCH 5/5] perf core: Reduce perf event output overhead by new overflow handler Wang Nan <wangnan0@huawei.com> - 2016-03-07 05:00 +0100
  [RESEND PATCH 4/5] perf core: Add backward attribute to perf event Wang Nan <wangnan0@huawei.com> - 2016-03-07 05:00 +0100
  [RESEND PATCH 3/5] perf core: Prepare writing into ring buffer from end Wang Nan <wangnan0@huawei.com> - 2016-03-07 05:00 +0100
  Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 14:50 +0100
    Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 14:50 +0100
      Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 15:00 +0100
        Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 16:30 +0100
          Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 16:40 +0100
            Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 17:00 +0100
              Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 17:20 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 17:30 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 17:40 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 17:40 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 17:50 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 17:50 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 18:10 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 18:30 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 18:30 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 18:40 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 18:50 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 18:50 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 19:00 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 19:00 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 19:10 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 19:30 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Ingo Molnar <mingo@kernel.org> - 2016-03-08 19:40 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-08 19:00 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 19:00 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 17:40 +0100
              Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Borislav Petkov <bp@alien8.de> - 2016-03-09 12:00 +0100
                Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Dmitry Vyukov <dvyukov@google.com> - 2016-03-09 12:30 +0100
        Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Jiri Olsa <jolsa@redhat.com> - 2016-03-08 21:00 +0100
          Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 21:10 +0100
            Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Jiri Olsa <jolsa@redhat.com> - 2016-03-08 21:50 +0100
              Re: [RESEND PATCH 0/5] perf core: Support overwrite ring buffer Peter Zijlstra <peterz@infradead.org> - 2016-03-08 22:10 +0100

csiph-web