What''s the difference of the three provider. It seems all could trace the high sys time. so any difference of usage boundary? -- This message posted from opensolaris.org
Chip Bennett
2007-Jul-05 04:02 UTC
[dtrace-discuss] syscall,unix and fbt provider difference
1) Yes, lots of overlap with syscall and fbt 2) Syscall is a standard published interface 3) fbt lets you get deeper, but could change from one release to the next 4) There is no "unix" provider. Chip wynne wrote:> What''s the difference of the three provider. > It seems all could trace the high sys time. so any difference of usage boundary? > -- > This message posted from opensolaris.org > _______________________________________________ > dtrace-discuss mailing list > dtrace-discuss at opensolaris.org >
unix is not a provider. And then there were two. :^)
The usage boundaries are based on what questions you seek answers to.
Yes, both syscall and fbt are useful for accounting for sys time.
System calls are the entry point into the kernel from applications, so
profiling at the syscall level allows you to see which system calls are
being
executed, by which threads, and various things about what the calls are
doing
(e.g. which files are being read by read(2), etc). Using time based
profiling
at the entry / return points gives you a sys time view, most useful on a per
process or per thread basis.
fbt provides probes for virtually all kernel functions, and is generally
more
useful when you''re chasing a particular behavior or performance issue
in
a specific kernel subsystem, or are just generally interested in
learning more
about how the kernel works.
For a simple kernel profile as a starting point:
#dtrace -n ''profile-997hz / arg0 != 0/ { @ks[stack()] = count();
}''
Or if it''s a particular CPU that''s spending time in the kernel
(as per
mpstat(1) output);
#dtrace -n ''profile-997hz / arg0 != 0 && cpu == <CPU_ID>
/ {
@ks[stack()]=count() }''
Or man lockstat(1).
/jim
wynne wrote:> What''s the difference of the three provider.
> It seems all could trace the high sys time. so any difference of usage
boundary?
> --
> This message posted from opensolaris.org
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
>