Re: [PATCH 02/14] hw/core/clock: trace clock values in Hz instead of ns

From: Damien Hedde <damien.hedde@greensocs.com>
To: "Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	"Luc Michel" <luc@lmichel.fr>,
	qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-arm@nongnu.org,
	Andrew Baumann <Andrew.Baumann@microsoft.com>
Subject: Re: [PATCH 02/14] hw/core/clock: trace clock values in Hz instead of ns
Date: Mon, 28 Sep 2020 10:42:00 +0200	[thread overview]
Message-ID: <41490d3c-e497-dbab-6e30-446ea9bffefd@greensocs.com> (raw)
In-Reply-To: <f5f6c8ca-d4f7-d06f-94d9-ded36ebf5753@amsat.org>


On 9/26/20 10:36 PM, Philippe Mathieu-Daudé wrote:
> On 9/25/20 12:17 PM, Luc Michel wrote:
>> The nanosecond unit greatly limits the dynamic range we can display in
>> clock value traces, for values in the order of 1GHz and more. The
>> internal representation can go way beyond this value and it is quite
>> common for today's clocks to be within those ranges.
>>
>> For example, a frequency between 500MHz+ and 1GHz will be displayed as
>> 1ns. Beyond 1GHz, it will show up as 0ns.
>>
>> Replace nanosecond periods traces with frequencies in the Hz unit
>> to have more dynamic range in the trace output.
> 
> I have a similar patch adding the freq but keeping the periods in
> case, as it might be a matter of taste (for me too the frequency
> is more meaningful).
> 
>>
>> Signed-off-by: Luc Michel <luc@lmichel.fr>
>> ---
>>  hw/core/clock.c      | 6 +++---
>>  hw/core/trace-events | 4 ++--
>>  2 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/core/clock.c b/hw/core/clock.c
>> index 7066282f7b..81184734e0 100644
>> --- a/hw/core/clock.c
>> +++ b/hw/core/clock.c
>> @@ -37,12 +37,12 @@ void clock_clear_callback(Clock *clk)
>>  bool clock_set(Clock *clk, uint64_t period)
>>  {
>>      if (clk->period == period) {
>>          return false;
>>      }
>> -    trace_clock_set(CLOCK_PATH(clk), CLOCK_PERIOD_TO_NS(clk->period),
>> -                    CLOCK_PERIOD_TO_NS(period));
>> +    trace_clock_set(CLOCK_PATH(clk), CLOCK_PERIOD_TO_HZ(clk->period),
>> +                    CLOCK_PERIOD_TO_HZ(period));
>>      clk->period = period;
>>  
>>      return true;
>>  }
>>  
>> @@ -52,11 +52,11 @@ static void clock_propagate_period(Clock *clk, bool call_callbacks)
>>  
>>      QLIST_FOREACH(child, &clk->children, sibling) {
>>          if (child->period != clk->period) {
>>              child->period = clk->period;
>>              trace_clock_update(CLOCK_PATH(child), CLOCK_PATH(clk),
>> -                               CLOCK_PERIOD_TO_NS(clk->period),
>> +                               CLOCK_PERIOD_TO_HZ(clk->period),
>>                                 call_callbacks);
>>              if (call_callbacks && child->callback) {
>>                  child->callback(child->callback_opaque);
>>              }
>>              clock_propagate_period(child, call_callbacks);
>> diff --git a/hw/core/trace-events b/hw/core/trace-events
>> index 1ac60ede6b..6f96d8bfd0 100644
>> --- a/hw/core/trace-events
>> +++ b/hw/core/trace-events
>> @@ -29,8 +29,8 @@ resettable_phase_exit_end(void *obj, const char *objtype, unsigned count) "obj=%
>>  resettable_transitional_function(void *obj, const char *objtype) "obj=%p(%s)"
>>  
>>  # clock.c
>>  clock_set_source(const char *clk, const char *src) "'%s', src='%s'"
>>  clock_disconnect(const char *clk) "'%s'"
>> -clock_set(const char *clk, uint64_t old, uint64_t new) "'%s', ns=%"PRIu64"->%"PRIu64
>> +clock_set(const char *clk, uint64_t old, uint64_t new) "'%s', %"PRIu64"hz->%"PRIu64"hz"
> 
> Unit is spell 'Hz'.
> 
>>  clock_propagate(const char *clk) "'%s'"
>> -clock_update(const char *clk, const char *src, uint64_t val, int cb) "'%s', src='%s', ns=%"PRIu64", cb=%d"
>> +clock_update(const char *clk, const char *src, uint64_t hz, int cb) "'%s', src='%s', val=%"PRIu64"hz cb=%d"
> 
> Ditto.
> 
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> 

Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>