From: Ingo Molnar <mingo@elte.hu>
Clean up the TSC-synchronization code: get rid of div64 and calm down the
printks.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/kernel/smpboot.c | 39 +++++--------------------------------
1 files changed, 6 insertions(+), 33 deletions(-)
diff -puN arch/i386/kernel/smpboot.c~tsc-synchronisation-cleanup arch/i386/kernel/smpboot.c
--- 25/arch/i386/kernel/smpboot.c~tsc-synchronisation-cleanup 2004-09-05 14:58:48.049055712 -0700
+++ 25-akpm/arch/i386/kernel/smpboot.c 2004-09-05 14:58:48.053055104 -0700
@@ -197,34 +197,6 @@ static unsigned long long tsc_values[NR_
#define NR_LOOPS 5
-/*
- * accurate 64-bit/32-bit division, expanded to 32-bit divisions and 64-bit
- * multiplication. Not terribly optimized but we need it at boot time only
- * anyway.
- *
- * result == a / b
- * == (a1 + a2*(2^32)) / b
- * == a1/b + a2*(2^32/b)
- * == a1/b + a2*((2^32-1)/b) + a2/b + (a2*((2^32-1) % b))/b
- * ^---- (this multiplication can overflow)
- */
-
-static unsigned long long __init div64 (unsigned long long a, unsigned long b0)
-{
- unsigned int a1, a2;
- unsigned long long res;
-
- a1 = ((unsigned int*)&a)[0];
- a2 = ((unsigned int*)&a)[1];
-
- res = a1/b0 +
- (unsigned long long)a2 * (unsigned long long)(0xffffffff/b0) +
- a2 / b0 +
- (a2 * (0xffffffff % b0)) / b0;
-
- return res;
-}
-
static void __init synchronize_tsc_bp (void)
{
int i;
@@ -234,7 +206,7 @@ static void __init synchronize_tsc_bp (v
unsigned long one_usec;
int buggy = 0;
- printk("checking TSC synchronization across %u CPUs: ", num_booting_cpus());
+ printk(KERN_INFO "checking TSC synchronization across %u CPUs: ", num_booting_cpus());
/* convert from kcyc/sec to cyc/usec */
one_usec = cpu_khz / 1000;
@@ -289,7 +261,8 @@ static void __init synchronize_tsc_bp (v
sum += t0;
}
}
- avg = div64(sum, num_booting_cpus());
+ avg = sum;
+ do_div(avg, num_booting_cpus());
sum = 0;
for (i = 0; i < NR_CPUS; i++) {
@@ -307,18 +280,18 @@ static void __init synchronize_tsc_bp (v
buggy = 1;
printk("\n");
}
- realdelta = div64(delta, one_usec);
+ realdelta = delta;
+ do_div(realdelta, one_usec);
if (tsc_values[i] < avg)
realdelta = -realdelta;
- printk("BIOS BUG: CPU#%d improperly initialized, has %ld usecs TSC skew! FIXED.\n", i, realdelta);
+ printk(KERN_INFO "CPU#%d had %ld usecs TSC skew, fixed it up.\n", i, realdelta);
}
sum += delta;
}
if (!buggy)
printk("passed.\n");
- ;
}
static void __init synchronize_tsc_ap (void)
_