[Just starting out with DTrace and was hoping to get some guidance.] I have a "benchmark" program that I monitored with both prstat (prstat -mL -P <PID>) and pfilestat (from the DTrace toolkit). Prstat reports LAT values in the 0.1-0.2% range, but pfilestat reports "waitcpu" values in the 6-10%. Since those two numbers supposedly represent time waiting for the CPU, I'm wondering why they are so different for the same application (over the same time period).
On a side note, the pfilestat script (I think) assumes that a "read entry" will be followed by a "read return" probe. On a per-thread basis, I can see this happening, but if the application has multiple threads/readers/writers, isn't it possible to get interleaved syscalls? For example, Thread1-> read entry Thread2 -> write entry Thread1 -> read return Thread2 -> write return If so, then shouldn't the pfilestat script be using thread local variables for timing versus globabl variables? -- This message posted from opensolaris.org _______________________________________________ dtrace-discuss mailing list [email protected]
