From 59893c116e9e4e5dd04c24c0ba2fd06fe1936500 Mon Sep 17 00:00:00 2001
From: Anton Kling <anton@kling.gg>
Date: Thu, 4 Jul 2024 20:22:32 +0200
Subject: scheduler: Use get_uptime() since it caches the result

Apparently getting the current TSC is a expensive operation. This change
had a significant improvements for I/O heavy applications.
---
 kernel/init/kernel.c     | 2 +-
 kernel/sched/scheduler.c | 2 +-
 kernel/timer.c           | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

(limited to 'kernel')

diff --git a/kernel/init/kernel.c b/kernel/init/kernel.c
index 868cfb1..61e863b 100644
--- a/kernel/init/kernel.c
+++ b/kernel/init/kernel.c
@@ -131,7 +131,7 @@ void kernel_main(u32 kernel_end, unsigned long magic, unsigned long addr,
     }
   }
   for (;;) {
-    current_task->sleep_until = timer_get_ms() + 100000000;
+    current_task->sleep_until = timer_get_uptime() + 100000000;
     wait_for_interrupt();
   }
 }
diff --git a/kernel/sched/scheduler.c b/kernel/sched/scheduler.c
index 10ecd73..a77e1e0 100644
--- a/kernel/sched/scheduler.c
+++ b/kernel/sched/scheduler.c
@@ -434,7 +434,7 @@ extern PageDirectory *active_directory;
 
 process_t *next_task(process_t *s) {
   process_t *c = s;
-  u64 ms_time = timer_get_ms();
+  u64 ms_time = timer_get_uptime();
   c = c->next;
   for (;; c = c->next) {
     if (!c) {
diff --git a/kernel/timer.c b/kernel/timer.c
index 21020b0..b00a24b 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -29,7 +29,7 @@ void timer_wait_for_init(void) {
 
 u64 timer_current_uptime = 0; // This gets updated by the PIT handler
 u64 timer_get_uptime(void) {
-  return tsc_calculate_ms(tsc_get());
+  return timer_current_uptime;
 }
 
 void timer_get(struct timespec *tp) {
-- 
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