This adds an initial 0.5s delay to calc_load so that it avoids updating
load at the same time as tasks scheduled using round_jiffies, otherwise
the load average is badly affected by tasks that run every time calc_load
does (currently every 5s).
I'm assuming this change doesn't affect the intention of round_jiffies,
to avoid tasks waking the cpu at different times, because calc_load is
already run very often by a call from update_times(ticks) on every timer
interrupt.
Signed-off-by: Simon Arlott <[EMAIL PROTECTED]>
Cc: Andrew Morton <[EMAIL PROTECTED]>
Cc: Arjan van de Ven <[EMAIL PROTECTED]>
---
Without this change or an appropriate equivalent, my change to cxacru
causes the load to stay around 1.00 even when mostly idle since it now
runs every second using round_jiffies:
[ 332.416288] cxacru_poll_status(..), jiffies=5000 [start]
[ 332.417312] calc_load(1), count=-1, jiffies=5001 [start]
[ 332.417322] calc_load(1), count=4999, jiffies=5001 [finish]
[ 332.423382] cxacru_poll_status(..), jiffies=5007, next=993 [finish]
kernel/timer.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/timer.c b/kernel/timer.c
index cb1b86a..4bb21b5 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1225,7 +1225,7 @@ EXPORT_SYMBOL(avenrun);
static inline void calc_load(unsigned long ticks)
{
unsigned long active_tasks; /* fixed-point */
- static int count = LOAD_FREQ;
+ static int count = LOAD_FREQ + HZ/2;
count -= ticks;
if (unlikely(count < 0)) {
--
1.5.0.1
--
Simon Arlott
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