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Add PBD::QPC::initialize to initialize timer and call it from PBD::init

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Check timer for invalid frequency
Precalculate timer tick rate to save a few instructions
Don't use static variables inside functions to avoid checking for initialization
Use static functions inside anonymous namespace for internal linkage
This commit is contained in:
Tim Mayberry 2015-09-16 23:21:38 +10:00
parent 9bd893a6a2
commit 119e56e7eb
3 changed files with 41 additions and 40 deletions
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63
libs/pbd/windows_timer_utils.cc
View file

@ -23,11 +23,15 @@
#include "pbd/compose.h"
#include "pbd/debug.h"
#include "pbd/error.h"
#include "i18n.h"
#define DEBUG_TIMING(msg) DEBUG_TRACE (PBD::DEBUG::Timing, msg);
namespace {
static
UINT&
timer_resolution ()
{
@ -35,7 +39,7 @@ timer_resolution ()
return timer_res_ms;
}
}
} // namespace
namespace PBD {
@ -100,6 +104,7 @@ reset_resolution ()
DEBUG_TIMING("Could not reset the Timer resolution.\n");
return false;
}
DEBUG_TIMING("Reset the Timer resolution.\n");
timer_resolution() = 0;
return true;
}
@ -108,34 +113,9 @@ reset_resolution ()
namespace {
bool&
qpc_frequency_success ()
{
static bool success = false;
return success;
}
LARGE_INTEGER
qpc_frequency ()
{
LARGE_INTEGER freq;
if (QueryPerformanceFrequency(&freq) == 0) {
DEBUG_TIMING ("Failed to determine frequency of QPC\n");
qpc_frequency_success() = false;
} else {
qpc_frequency_success() = true;
}
return freq;
}
LARGE_INTEGER
qpc_frequency_cached ()
{
static LARGE_INTEGER frequency = qpc_frequency ();
return frequency;
}
static double timer_rate_us = 0.0;
static
bool
test_qpc_validity ()
{
@ -159,25 +139,37 @@ namespace QPC {
bool
check_timer_valid ()
{
// setup caching the timer frequency
qpc_frequency_cached ();
if (!qpc_frequency_success ()) {
if (!timer_rate_us) {
return false;
}
return test_qpc_validity ();
}
bool
initialize ()
{
LARGE_INTEGER freq;
if (!QueryPerformanceFrequency(&freq) || freq.QuadPart < 1) {
info << X_("Failed to determine frequency of QPC\n") << endmsg;
timer_rate_us = 0;
} else {
timer_rate_us = 1000000.0 / freq.QuadPart;
}
info << string_compose(X_("QPC timer microseconds per tick: %1\n"),
timer_rate_us) << endmsg;
return !timer_rate_us;
}
int64_t
get_microseconds ()
{
LARGE_INTEGER current_val;
if (qpc_frequency_success()) {
if (timer_rate_us) {
// MS docs say this will always succeed for systems >= XP but it may
// not return a monotonic value with non-invariant TSC's etc
if (QueryPerformanceCounter(&current_val) != 0) {
return (int64_t)(((double)current_val.QuadPart) /
((double)qpc_frequency_cached().QuadPart) * 1000000.0);
return (int64_t)(current_val.QuadPart * timer_rate_us);
}
}
DEBUG_TIMING ("Could not get QPC timer\n");
@ -189,8 +181,7 @@ get_microseconds ()
int64_t
get_microseconds ()
{
qpc_frequency_cached();
if (qpc_frequency_success()) {
if (timer_rate_us) {
return QPC::get_microseconds ();
}
// For XP systems that don't support a high-res performance counter