From fb80091ac322c8a41bf8b983499596b5eec356b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gustaf=20Alh=C3=A4ll?= <gustaf@hanicef.me>
Date: Mon, 6 Jan 2025 09:49:04 +0100
Subject: [PATCH] Double slack time for busy-wait
---
src/dedicated/i_system.c | 23 ++++++++++++++++-------
src/sdl/i_system.c | 2 +-
2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/src/dedicated/i_system.c b/src/dedicated/i_system.c
index 23c0149ca7..79cdd9bb6d 100644
--- a/src/dedicated/i_system.c
+++ b/src/dedicated/i_system.c
@@ -376,13 +376,22 @@ void I_SleepDuration(precise_t duration)
{
#if defined(__linux__) || defined(__FreeBSD__)
UINT64 precision = I_GetPrecisePrecision();
- struct timespec ts = {
- .tv_sec = duration / precision,
- .tv_nsec = duration * 1000000000 / precision % 1000000000,
- };
- int status;
- do status = clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, &ts);
- while (status == EINTR);
+ precise_t dest = I_GetPreciseTime() + duration;
+ precise_t slack = (precision / 5000); // 0.2 ms slack
+ if (duration > slack)
+ {
+ duration -= slack;
+ struct timespec ts = {
+ .tv_sec = duration / precision,
+ .tv_nsec = duration * 1000000000 / precision % 1000000000,
+ };
+ int status;
+ do status = clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, &ts);
+ while (status == EINTR);
+ }
+
+ // busy-wait the rest
+ while (((INT64)dest - (INT64)I_GetPreciseTime()) > 0);
#else
UINT64 precision = I_GetPrecisePrecision();
INT32 sleepvalue = cv_sleep.value;
diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c
index f32d97e227..f78f74d57c 100644
--- a/src/sdl/i_system.c
+++ b/src/sdl/i_system.c
@@ -2310,7 +2310,7 @@ void I_SleepDuration(precise_t duration)
#if defined(__linux__) || defined(__FreeBSD__) || defined(__HAIKU__)
UINT64 precision = I_GetPrecisePrecision();
precise_t dest = I_GetPreciseTime() + duration;
- precise_t slack = (precision / 10000); // 0.1 ms slack
+ precise_t slack = (precision / 5000); // 0.2 ms slack
if (duration > slack)
{
duration -= slack;
--
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