Current btrace has `interval:hz:1` probe that makes periodically events.
`interval:hz:1` looks to make events once per second (= 1Hz),
but current implementation makes once per tick (= 100Hz on amd64).
I think the interval should be counted by reciprocal of ticks so that fit to Hz.
Following patch changes to calculate 'dp_maxtick' fit to Hz.
'dtrq_rate' has number of hz. I think it should be allowed same value of 'hz'
so that we can use `interval:hz:100` that equals to once per tick on amd64.
Index: dt_prov_profile.c
===================================================================
RCS file: /cvs/src/sys/dev/dt/dt_prov_profile.c,v
retrieving revision 1.2
diff -u -p -r1.2 dt_prov_profile.c
--- dt_prov_profile.c 25 Mar 2020 14:59:23 -0000 1.2
+++ dt_prov_profile.c 23 Jun 2020 02:02:27 -0000
@@ -75,7 +75,7 @@ dt_prov_profile_alloc(struct dt_probe *d
KASSERT(TAILQ_EMPTY(plist));
KASSERT(dtp == dtpp_profile || dtp == dtpp_interval);
- if (dtrq->dtrq_rate <= 0 || dtrq->dtrq_rate >= hz)
+ if (dtrq->dtrq_rate <= 0 || dtrq->dtrq_rate > hz)
return EOPNOTSUPP;
CPU_INFO_FOREACH(cii, ci) {
@@ -88,7 +88,7 @@ dt_prov_profile_alloc(struct dt_probe *d
return ENOMEM;
}
- dp->dp_maxtick = dtrq->dtrq_rate;
+ dp->dp_maxtick = hz / dtrq->dtrq_rate;
dp->dp_cpuid = ci->ci_cpuid;
dp->dp_filter = dtrq->dtrq_filter;
--
Yuichiro NAITO
[email protected]
