CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2024/02/09 10:42:18
Modified files:
sys/dev/dt : dt_prov_profile.c dt_dev.c dtvar.h
sys/kern : kern_clock.c
Log message:
dt(4): move interval/profile entry points to dedicated clockintr callback
To improve the utility of dt(4)'s interval and profile probes we need
to move the probe entry points from the fixed-frequency hardclock() to
a dedicated clock interrupt callback so that the probes can fire at
arbitrary frequencies.
- Remove entry points for interval/profile probes from hardclock().
- Merge dt_prov_profile_enter(), dt_prov_interval_enter(), and
dt_prov_profile_fire() into one function, dt_clock(). This is
the now-unified callback for interval/profile probes. dt_clock()
will consume multiple events during a single execution if it is
delayed, but on platforms with high quality interrupt clocks this
should be rare.
- Each struct dt_pcb gets its own clockintr handle, dp_clockintr.
- In struct dt_pcb, replace dp_maxtick/dp_nticks with dp_nsecs,
the PCB's sampling period. Aynchronous probes must initialize
dp_nsecs to a non-zero value during dtpv_alloc().
- In struct dt_pcb, replace dp_cpuid with dp_cpu so that
dt_ioctl_record_start() knows where to bind the PCB's
dp_clockintr.
- dt_ioctl_record_start() binds, staggers, and starts all
interval/profile PCBs on the given dt_softc. Each dp_clockintr
is given a reference to its enclosing PCB so that dt_clock()
doesn't need to search for it. The staggering sort-of simulates
the current behavior under hardclock().
- dt_ioctl_record_stop() unbinds all interval/profile PCBs. The
CL_BARRIER ensures that dp_clockintr's PCB reference is not in
use by dt_clock() so that the PCB may be safely freed upon
return from dt_ioctl_record_stop(). Blocking while holding
dt_lock is not ideal, but in practice blocking in this spot is
rare and dt_clock() completes quickly on all but the oldest
hardware. An extremely unlucky thread could block for every
interval/profile PCB on the softc, but this is implausible.
DT_FA_PROFILE values are up-to-date for amd64, i386, and macppc.
Somebody with the right hardware needs to check-and-maybe-fix the
values on octeon, powerpc64, and sparc64.
Joint effort with mpi@.
Thread: https://marc.info/?l=openbsd-tech&m=170629371821879&w=2
ok mpi@
