Messages in this thread | | | Date | Mon, 18 Sep 2006 10:15:55 +0200 | From | Jes Sorensen <> | Subject | Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108 |
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Mathieu Desnoyers wrote: > And about those extra cycles.. according to : > Documentation/kprobes.txt > "6. Probe Overhead > > On a typical CPU in use in 2005, a kprobe hit takes 0.5 to 1.0 > microseconds to process. Specifically, a benchmark that hits the same > probepoint repeatedly, firing a simple handler each time, reports 1-2 > million hits per second, depending on the architecture. A jprobe or > return-probe hit typically takes 50-75% longer than a kprobe hit. > When you have a return probe set on a function, adding a kprobe at > the entry to that function adds essentially no overhead. [snip] > So, 1 microsecond seems more like 1500-2000 cycles to me, not 50.
So call it 2000 cycles, now go measure it in *real* life benchmarks and not some artificial I call this one syscall that hits the probe every time in a tight loop, kinda thing.
Show us some *real* numbers please.
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