Same problem as Arvids and Andreas:
LD .tmp_vmlinux1
drivers/built-in.o: In function `menu_select':
menu.c:(.text+0x139711): undefined reference to `__udivdi3'
make: *** [.tmp_vmlinux1] Error 1
Reading specs from /usr/lib/gcc/i686-pc-linux-gnu/3.4.5/specs
Configured with: ./configure --prefix=/usr --enable-shared --enable-languages=c,c++ --enable-threads=posix --with-slibdir=/lib --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 3.4.5
This is a custom build of Linux based on Linux From Scratch. I've had no issues with 2.6.31.X
--
Mike Garrison-
The new menu governor driver is written by Intel folks who never use 32-bit
anymore it seems :-)
---------------------------------------------------------
Subject: [PATCH] menu: use proper 64 bit math
The new menu governor is incorrectly doing a 64 bit divide.
Compile tested only
Signed-off-by: Stephen Hemminger <[email protected]>
--- a/drivers/cpuidle/governors/menu.c 2009-12-21 12:02:25.840083589 -0800
+++ b/drivers/cpuidle/governors/menu.c 2009-12-21 12:16:42.418834255 -0800
@@ -18,6 +18,7 @@
#include <linux/hrtimer.h>
#include <linux/tick.h>
#include <linux/sched.h>
+#include <linux/math64.h>
#define BUCKETS 12
#define RESOLUTION 1024
@@ -169,6 +170,12 @@ static DEFINE_PER_CPU(struct menu_device
static void menu_update(struct cpuidle_device *dev);
+/* This implements DIV_ROUND_CLOSEST but avoids 64 bit division */
+static u64 div_round64(u64 dividend, u32 divisor)
+{
+ return div_u64(dividend + (divisor / 2), divisor);
+}
+
/**
* menu_select - selects the next idle state to enter
* @dev: the CPU
@@ -209,9 +216,8 @@ static int menu_select(struct cpuidle_de
data->correction_factor[data->bucket] = RESOLUTION * DECAY;
/* Make sure to round up for half microseconds */
- data->predicted_us = DIV_ROUND_CLOSEST(
- data->expected_us * data->correction_factor[data->bucket],
- RESOLUTION * DECAY);
+ data->predicted_us = div_round64(data->expected_us * data->correction_factor[data->bucket],
+ RESOLUTION * DECAY);
/*
* We want to default to C1 (hlt), not to busy polling
On 12/21/2009 21:21, Stephen Hemminger wrote:
> The new menu governor driver is written by Intel folks who never use 32-bit
> anymore it seems :-)
more like "by people who use a compiler that knows how to divide by a power of 2" :)