On 11/16/15 5:12 PM, Arnaldo Carvalho de Melo wrote:
Em Mon, Nov 16, 2015 at 01:08:15PM -0500, Frank Ch. Eigler escreveu:
Olga.Kornievskaia wrote:
[...] say there are two tracepoints ?foobar_enter? and
?foobar_exit?. Each tracepoint logs a timestamp. I?d like to be able
to say that on average it takes that many time-units between ?enter?
and ?exit? tracepoints. [...]
For completeness, a complete systemtap implementation of this could look like:
# stap -e '
global s, t%
probe kernel.trace("foobar_enter") {
t[tid()]=gettimeofday_us()
}
probe kernel.trace("foobar_exit") {
if (tid() in t) { s <<< gettimeofday_us() - t[tid()] }
}
probe timer.s(5),end {
printf("cumulative average us: %d\n", @avg(s))
}
'
Is that done syncronously?
Interesting solution. How does it scale with CPUs and tasks?
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