Messages in this thread | | | Date | Wed, 17 Dec 2008 17:42:54 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v6 6/7] sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0 |
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On Wed, 17 Dec 2008 22:57:38 +0530 Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote:
> --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -782,6 +782,16 @@ enum powersavings_balance_level { > ((sched_mc_power_savings || sched_smt_power_savings) ? \ > SD_POWERSAVINGS_BALANCE : 0)
What's with all the crappy macros in here?
> +/* > + * Optimise SD flags for power savings: > + * SD_BALANCE_NEWIDLE helps agressive task consolidation and power savings. > + * Keep default SD flags if sched_{smt,mc}_power_saving=0 > + */ > + > +#define POWERSAVING_SD_FLAGS \ > + ((sched_mc_power_savings || sched_smt_power_savings) ? \ > + SD_BALANCE_NEWIDLE : 0)
This one purports to be a constant, but it isn't - it's code.
It would be cleaner, clearer and more idiomatic to do
static inline int powersaving_sd_flags(void) { ... }
Also, doing (sched_mc_power_savings | sched_smt_power_saving) might save a branch.
> #define test_sd_parent(sd, flag) ((sd->parent && \ > (sd->parent->flags & flag)) ? 1 : 0)
buggy when passed an expression with side-effects. Doesn't need to be implemented as a macro.
Sigh.
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