[PATCH 2/4] hw/core/clock: trace clock values in Hz instead of ns

[Philippe Mathieu-Daudé]

From: Luc Michel <luc@lmichel.fr>

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.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20201010135759.437903-3-luc@lmichel.fr>
[PMD: Replace CLOCK_PERIOD_TO_HZ() by clock_get_hz()]
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/core/clock.c      | 8 +++++---
 hw/core/trace-events | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/hw/core/clock.c b/hw/core/clock.c
index f866717a835..5cc9599ba3a 100644
--- a/hw/core/clock.c
+++ b/hw/core/clock.c
@@ -51,12 +51,14 @@ void clock_clear_callback(Clock *clk)
 
 bool clock_set(Clock *clk, uint64_t period)
 {
+    uint64_t old_hz;
+
     if (clk->period == period) {
         return false;
     }
-    trace_clock_set(CLOCK_PATH(clk), CLOCK_PERIOD_TO_NS(clk->period),
-                    CLOCK_PERIOD_TO_NS(period));
+    old_hz = clock_get_hz(clk);
     clk->period = period;
+    trace_clock_set(CLOCK_PATH(clk), old_hz, clock_get_hz(clk));
 
     return true;
 }
@@ -69,7 +71,7 @@ static void clock_propagate_period(Clock *clk, bool 
call_callbacks)
         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_get_hz(clk),
                                call_callbacks);
             if (call_callbacks && child->callback) {
                 child->callback(child->callback_opaque);
diff --git a/hw/core/trace-events b/hw/core/trace-events
index 1ac60ede6b7..7b2869cbaab 100644
--- a/hw/core/trace-events
+++ b/hw/core/trace-events
@@ -31,6 +31,6 @@ 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"
 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"
-- 
2.26.2