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[MIPS] SMP: Get smp_tune_scheduling to do something useful.

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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle 2007-02-21 00:10:19 +00:00
parent 9693a85378
commit de7fa296b6
1 changed files with 4 additions and 21 deletions
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25
arch/mips/kernel/smp.c
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@ -51,31 +51,14 @@ int __cpu_logical_map[NR_CPUS]; /* Map logical to physical */
EXPORT_SYMBOL(phys_cpu_present_map);
EXPORT_SYMBOL(cpu_online_map);
/* This happens early in bootup, can't really do it better */
static void smp_tune_scheduling (void)
{
struct cache_desc *cd = &current_cpu_data.scache;
unsigned long cachesize; /* kB */
unsigned long cpu_khz;
unsigned long cachesize = cd->linesz * cd->sets * cd->ways;
/*
* Crude estimate until we actually meassure ...
*/
cpu_khz = loops_per_jiffy * 2 * HZ / 1000;
/*
* Rough estimation for SMP scheduling, this is the number of
* cycles it takes for a fully memory-limited process to flush
* the SMP-local cache.
*
* (For a P5 this pretty much means we will choose another idle
* CPU almost always at wakeup time (this is due to the small
* L1 cache), on PIIs it's around 50-100 usecs, depending on
* the cache size)
*/
if (!cpu_khz)
return;
cachesize = cd->linesz * cd->sets * cd->ways;
if (cachesize > max_cache_size)
max_cache_size = cachesize;
}
extern void __init calibrate_delay(void);