On Jun 25, 9:32am, m...@3am-software.com (Matt Thomas) wrote: -- Subject: Re: DTrace syscall provider - please test/comment
| | On Jun 25, 2013, at 5:25 AM, chris...@zoulas.com (Christos Zoulas) wrote: | | > On Jun 24, 6:12pm, m...@3am-software.com (Matt Thomas) wrote: | > -- Subject: Re: DTrace syscall provider - please test/comment | > | > | | > | On Jun 24, 2013, at 6:01 PM, Christos Zoulas <chris...@astron.com> wrote: | > | | > | > Can't this be done as an addition/enhancement to the trace_enter()/ | > | > trace_exit() facility instead of having to enter each syscall entry? | > | | > | that only gets called if p->p_trace_enabled is set. So now you need | > | a hook to set that on every lwp switch if the provider is tracing. | > | > Right, and it (dtrace) can set a different (or the same flag) to enable | > it. | | | How does it set the same flag since that's per-proc and will need to changed | on context switch. | | A different flag is more overhead per syscall. I am trying to balance that against adding of two more conditionals per syscall per architecture and touching dozens of source files adding the same code in each one. Perhaps the syscall_plain/syscall_fancy idea was not that bad after all :-( Perhaps a different bit on the same flag. If any of them is set, you call trace enter, and you clear/move the bit on context switch. christos
