dtrace_tips

More documents

Recommendations

Info

Gotcha: Using system● system is processed at user-level –there will be a delay between probefiring and command execution,bounded by the switchrate●Be careful; it's easy to accidentallycreate a positive feedback loop:●<strong>dtrace</strong> -n 'proc:::exec{system(“/usr/ccs/bin/size %s”, args[0])}'●To avoid this, add a predicate to above:●/!progenyof($pid)/
Trick: system(“<strong>dtrace</strong>”)●●●In DTrace, actions cannot enable probesHowever, using the system action,one D script can launch anotherIf instrumenting processes, steps canbe taken to eliminate lossiness:– stop in parent– Pass the stopped process as an argument to thechild script– Use system to prun(1) in a BEGIN clause inthe child script
Page 1 and 2: Advanced DTraceTips, Tricks and Got
Page 3 and 4: DTrace Tips●●●Tips are pointe
Page 5 and 6: DTrace Gotchas●●●Like any sys
Page 7 and 8: Tip: Speculative tracing●●●
Page 9 and 10: Tip: clear and tick probes●●cle
Page 11 and 12: Tip: stop●●One may wish to stop
Page 13 and 14: Gotcha: stop gone haywire●●●B
Page 17 and 18: Gotcha: Too many pid probes●●
Page 20 and 21: Gotcha: Buffer drops●●●●The
Page 25 and 26: Trick: Tracking object lifetime●
Page 27: Tip: Using system●●Use the syst
Page 31 and 32: Gotcha: Stripped user stacks●●
Page 33 and 34: Trick: Using stop and ustack●●
Page 35 and 36: Tip: Ring buffering and -c/-p●●
Page 37 and 38: Tip: Tuning the deadman●●If the
Page 39 and 40: Trick: Watchpoints via pid●●●
Page 41 and 42: Trick: Iterating over structures●
Page 43 and 44: Gotcha: Unsporting functions●●
Page 45 and 46: Trick: sizeof and profiling●●
Page 47 and 48: Gotcha: $target evaluation●●●
Page 49 and 50: Gotcha: Data model mismatch●●
Page 51 and 52: Tip: Sample with profile●●●Wh
Page 53 and 54: Gotcha: vtimestamp●●●●vtime
Page 55 and 56: Tip: Demo DTrace scripts●●●/u

dtrace_tips

Create successful ePaper yourself

Delete template?

Save as template?