Minor factual errors regarding systemtap

Posted Aug 7, 2007 22:10 UTC (Tue) by fuhchee (guest, #40059)
In reply to: Minor factual errors regarding systemtap by oak
Parent article: On DTrace envy

> [on ARM a] single Systemtap syscall probe seems to have about as much
> performance hit for the system as the whole LTT(ng) thing.

Please post some details to the mailing list.

> Does this result sound right (LTT uses static probe points whereas Systemtap
> uses dynamic kprobe + has its own overhead on top of that)?

Yes, dynamic probes are significantly costly than static probe points,
but overall cost is a function that includes rate-of-hits and other
quantities. Note that the LTT static probe points will be transparently
exploitable from systemtap once this part of LTT is merged upstream,
and this should greatly reduce the performance differences.