trafgen: minor fix to help text for option "--no-sock-mem" - netsniff-ng.git - A high-performance Linux networking toolkit

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author	Jesper Dangaard Brouer <brouer@redhat.com>	2014-08-21 16:42:44 +0200
committer	Jesper Dangaard Brouer <brouer@redhat.com>	2014-08-21 16:47:06 +0200
commit	9315977726e1179651e802261e6d19a83c5007fb (patch)
tree	7c216ab09f94b3a25cf73a852310eed175825227 /xmalloc.h
parent	76486ece10c6dbada8d78bbe50aa8254d3496a47 (diff)

trafgen: minor fix to help text for option "--no-sock-mem"

Pushed last commit a bit too fast. The help text described that the single letter option for "--no-sock-mem" were "-m", which is wrong the right option is "-A" (only help txt, correct in the code and manual). Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>

Diffstat (limited to 'xmalloc.h')

0 files changed, 0 insertions, 0 deletions

30% ) The first run above is without any tracing, just to get a based figure. hackbench takes ~0.79 seconds to run on the system. The second run enables tracing all events where nothing is filtered. This increases the time by 100% and hackbench takes 1.57 seconds to run. The third run filters all events where the preempt count will equal "20" (this should never happen) thus all events are discarded. This takes 1.69 seconds to run. This is 10% slower than just committing the events! The last run enables all events and filters where the filter will commit all events, and this takes 1.70 seconds to run. The filtering overhead is approximately 10%. Thus, the discard and commit of an event from the ring buffer may be about the same time. With this patch, the numbers change: # trace-cmd start -p nop # perf stat -r 10 hackbench 50 0.778233033 seconds time elapsed ( +- 0.38% ) # trace-cmd start -e all # perf stat -r 10 hackbench 50 1.582102692 seconds time elapsed ( +- 0.28% ) # trace-cmd start -e all -f 'common_preempt_count==20' # perf stat -r 10 hackbench 50 1.309230710 seconds time elapsed ( +- 0.22% ) # trace-cmd start -e all -f 'common_preempt_count!=20' # perf stat -r 10 hackbench 50 1.786001924 seconds time elapsed ( +- 0.20% ) The first run is again the base with no tracing. The second run is all tracing with no filtering. It is a little slower, but that may be well within the noise. The third run shows that discarding all events only took 1.3 seconds. This is a speed up of 23%! The discard is much faster than even the commit. The one downside is shown in the last run. Events that are not discarded by the filter will take longer to add, this is due to the extra copy of the event. Cc: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

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