Messages in this thread | | | Date | Sun, 06 Jun 2010 11:08:31 +0300 | From | Avi Kivity <> | Subject | Re: Perf trace event parse errors for KVM events |
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On 06/04/2010 12:57 AM, Steven Rostedt wrote: > On Tue, 2010-06-01 at 15:39 +0300, Avi Kivity wrote: > >> On 06/01/2010 02:59 PM, Steven Rostedt wrote: >> > >> I meant that viewing would be slowed down. It's an important part of >> using ftrace! >> >> How long does the Python formatter take to process 100k or 1M events? >> >> > I finally got around to testing this. > > I ran a trace on lock_acquire, and traced 1,253,296 events. > > I then created a python plugin to analyze the trace: > > ---- > def lock_acquire(trace_seq, event): > t = '' > r = '' > if int(event['flags'])& 1: > t = 'try' > if int(event['flags'])& 2: > r = 'read' > trace_seq.puts('t %x %s%s%s' % ( > event['lockdep_addr'], t, r, > event['name'])) > > def register(pevent): > pevent.register_event_handler("lock", "lock_acquire", lock_acquire) > ---- > > Disclaimer, I'm not a python expert, and I'm sure the above python code > sucks. >
I think Python more or less guarantees your code will suck no matter what you do.
> [root@ixf9 trace-cmd.git]# time ./trace-cmd report -N>/dev/null 2>&1 > > real 0m4.653s > user 0m4.234s > sys 0m0.419s > > * -N keeps trace-cmd from loading any plugins. > > > [root@ixf9 trace-cmd.git]# time PYTHONPATH=`pwd` ./trace-cmd report>/dev/null 2>&1 > > real 0m53.916s > user 0m53.047s > sys 0m0.859s > > > Yes, running a python interpreter is a bit more expensive. It took 4 > seconds to read the million events with plain C, but 53 seconds to read > it in python. > > That said... This would only affect you if you were writing this to a > file. I doubt that you would notice this if you were scanning the trace > with less. >
I'm more worried about searching with less. But a minute for a million events isn't that bad.
> Also, I kicked this off in kernelshark, and it made no difference that I > can see. This is because kernelshark only evaluates the viewable area of > the screen. >
Neat. Can it also search? Where can I find it? <googles, finds, gawks>
-- error compiling committee.c: too many arguments to function
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