diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-23 12:53:48 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-23 12:53:48 -0700 |
| commit | 15a3d11b0f2ebdfb3591e411e268aa81998d4723 (patch) | |
| tree | 56e1d7715653871f015341c7edabd08045f5fc28 /include/linux/sched.h | |
| parent | 1f3a8e093f470ef193b0ca6011d90180331c8b53 (diff) | |
| parent | c8b281161dfa4bb5d5be63fb036ce19347b88c63 (diff) | |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Increase SCHED_LOAD_SCALE resolution
sched: Introduce SCHED_POWER_SCALE to scale cpu_power calculations
sched: Cleanup set_load_weight()
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 340f5ee57334..aaf71e08222c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -786,17 +786,39 @@ enum cpu_idle_type { }; /* - * sched-domains (multiprocessor balancing) declarations: + * Increase resolution of nice-level calculations for 64-bit architectures. + * The extra resolution improves shares distribution and load balancing of + * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup + * hierarchies, especially on larger systems. This is not a user-visible change + * and does not change the user-interface for setting shares/weights. + * + * We increase resolution only if we have enough bits to allow this increased + * resolution (i.e. BITS_PER_LONG > 32). The costs for increasing resolution + * when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the + * increased costs. */ +#if BITS_PER_LONG > 32 +# define SCHED_LOAD_RESOLUTION 10 +# define scale_load(w) ((w) << SCHED_LOAD_RESOLUTION) +# define scale_load_down(w) ((w) >> SCHED_LOAD_RESOLUTION) +#else +# define SCHED_LOAD_RESOLUTION 0 +# define scale_load(w) (w) +# define scale_load_down(w) (w) +#endif -/* - * Increase resolution of nice-level calculations: - */ -#define SCHED_LOAD_SHIFT 10 +#define SCHED_LOAD_SHIFT (10 + SCHED_LOAD_RESOLUTION) #define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT) -#define SCHED_LOAD_SCALE_FUZZ SCHED_LOAD_SCALE +/* + * Increase resolution of cpu_power calculations + */ +#define SCHED_POWER_SHIFT 10 +#define SCHED_POWER_SCALE (1L << SCHED_POWER_SHIFT) +/* + * sched-domains (multiprocessor balancing) declarations: + */ #ifdef CONFIG_SMP #define SD_LOAD_BALANCE 0x0001 /* Do load balancing on this domain. */ #define SD_BALANCE_NEWIDLE 0x0002 /* Balance when about to become idle */ |