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Optimize tickless interrupt latency 

Remove unnecessary critical sections from the SysTimer code since
the access should already be serialized.
pull/9786/head
Russ Butler 2019-02-21 17:42:01 -06:00
parent d43ca21ec5
commit f6ed7cee41
1 changed files with 8 additions and 10 deletions
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18
rtos/TARGET_CORTEX/SysTimer.cpp
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@ -87,14 +87,13 @@ void SysTimer::setup_irq()
void SysTimer::suspend(uint32_t ticks) void SysTimer::suspend(uint32_t ticks)
{ {
core_util_critical_section_enter(); // Remove ensures serialized access to SysTimer by stopping timer interrupt
remove(); remove();
schedule_tick(ticks);
_suspend_time_passed = false; _suspend_time_passed = false;
_suspended = true; _suspended = true;
core_util_critical_section_exit(); schedule_tick(ticks);
} }
bool SysTimer::suspend_time_passed() bool SysTimer::suspend_time_passed()
@ -104,11 +103,11 @@ bool SysTimer::suspend_time_passed()
uint32_t SysTimer::resume() uint32_t SysTimer::resume()
{ {
core_util_critical_section_enter(); // Remove ensures serialized access to SysTimer by stopping timer interrupt
remove();
_suspended = false; _suspended = false;
_suspend_time_passed = true; _suspend_time_passed = true;
remove();
uint64_t elapsed_ticks = (ticker_read_us(_ticker_data) - _time_us) / US_IN_TICK; uint64_t elapsed_ticks = (ticker_read_us(_ticker_data) - _time_us) / US_IN_TICK;
if (elapsed_ticks > 0) { if (elapsed_ticks > 0) {
@ -121,7 +120,6 @@ uint32_t SysTimer::resume()
_time_us += elapsed_ticks * US_IN_TICK; _time_us += elapsed_ticks * US_IN_TICK;
_tick += elapsed_ticks; _tick += elapsed_ticks;
core_util_critical_section_exit();
return elapsed_ticks; return elapsed_ticks;
} }
@ -136,11 +134,9 @@ void SysTimer::schedule_tick(uint32_t delta)
void SysTimer::cancel_tick() void SysTimer::cancel_tick()
{ {
core_util_critical_section_enter(); // Underlying call is interrupt safe
remove(); remove();
core_util_critical_section_exit();
} }
uint32_t SysTimer::get_tick() uint32_t SysTimer::get_tick()
@ -150,6 +146,8 @@ uint32_t SysTimer::get_tick()
us_timestamp_t SysTimer::get_time() us_timestamp_t SysTimer::get_time()
{ {
// Underlying call is interrupt safe
return ticker_read_us(_ticker_data); return ticker_read_us(_ticker_data);
} }