Messages in this thread | | | Date | Wed, 1 Jun 2011 12:18:13 -0400 | From | Chris Metcalf <> | Subject | Re: [PATCH 6/6] clocksource: tile: convert to use clocksource_register_hz |
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On 6/1/2011 3:32 AM, John Stultz wrote: > From: John Stultz <johnstul@us.ibm.com> > > Convert tile to use clocksource_register_hz. > > Untested. Help from maintainers would be appreciated. > > CC: Chris Metcalf <cmetcalf@tilera.com>
This patch boots up fine on tile. It provides a shift count of 31, with a mult value in the billions. This does mean that clocksource_cyc2ns() will only be able to give correct timer conversions for up to about 9 seconds. Is this believed to be adequate for all the uses the cycle counter is put to? I can run our normal regression tests, but I'd like to get a high-level sanity check from the clocksource folks.
The original shift of 22 was put in by commit 749dc6f252b57d5cb9c1f4c1c4aafe4c92a28207 back in August.
> CC: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: John Stultz <johnstul@us.ibm.com> > --- > arch/tile/kernel/time.c | 5 +---- > 1 files changed, 1 insertions(+), 4 deletions(-) > > diff --git a/arch/tile/kernel/time.c b/arch/tile/kernel/time.c > index c4be58c..f6f50f2a 100644 > --- a/arch/tile/kernel/time.c > +++ b/arch/tile/kernel/time.c > @@ -78,7 +78,6 @@ static struct clocksource cycle_counter_cs = { > .rating = 300, > .read = clocksource_get_cycles, > .mask = CLOCKSOURCE_MASK(64), > - .shift = 22, /* typical value, e.g. x86 tsc uses this */ > .flags = CLOCK_SOURCE_IS_CONTINUOUS, > }; > > @@ -91,8 +90,6 @@ void __init setup_clock(void) > cycles_per_sec = hv_sysconf(HV_SYSCONF_CPU_SPEED); > sched_clock_mult = > clocksource_hz2mult(cycles_per_sec, SCHED_CLOCK_SHIFT); > - cycle_counter_cs.mult = > - clocksource_hz2mult(cycles_per_sec, cycle_counter_cs.shift); > } > > void __init calibrate_delay(void) > @@ -107,7 +104,7 @@ void __init calibrate_delay(void) > void __init time_init(void) > { > /* Initialize and register the clock source. */ > - clocksource_register(&cycle_counter_cs); > + clocksource_register_hz(&cycle_counter_cs, cycles_per_sec); > > /* Start up the tile-timer interrupt source on the boot cpu. */ > setup_tile_timer();
-- Chris Metcalf, Tilera Corp. http://www.tilera.com
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