Messages in this thread | | | Date | Thu, 18 Dec 2008 20:52:30 +0530 | From | Vaidyanathan Srinivasan <> | Subject | Re: [PATCH v6 6/7] sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0 |
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* Ingo Molnar <mingo@elte.hu> [2008-12-18 13:46:44]:
> > * Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote: > > > * Andrew Morton <akpm@linux-foundation.org> [2008-12-17 17:42:54]: > > > > > 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? > > > > Hi Andrew, > > > > These macros set the SD_POWERSAVINGS_BALANCE flag based on the > > sysfs tunable. > > > > > > +/* > > > > + * 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) > > > { > > > ... > > > } > > > > Your are suggesting to move these to inline functions. I will write > > a patch and post for review. > > > > > 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. > > > > Agreed, but these macros are used throughout sched.c and are performance > > sensitive. Inline functions are a close enough replacement for the > > macro let me look for any performance penalty as well and report. > > those macros are historic so feel free to convert them to inlines without > re-measuring performance impact.
Sure Ingo. I will go ahead and change them in my next iteration.
> The patchset looks pretty good in principle otherwise, so if you could > address Andrew's comments and clean up those bits in the next iteration we > could start testing it in the scheduler tree. (Please also add Balbir > Singh's acks to the next iteration.)
Thank you for acking the patch. I will address Andrew's comments and post the next iteration along with Balbir's acks.
> and please fix your mailer to not inject stuff like this: > > Mail-Followup-To: Andrew Morton <akpm@linux-foundation.org>, > linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com, > venkatesh.pallipadi@intel.com, a.p.zijlstra@chello.nl, > mingo@elte.hu, dipankar@in.ibm.com, balbir@linux.vnet.ibm.com, > vatsa@linux.vnet.ibm.com, ego@in.ibm.com, andi@firstfloor.org, > davecb@sun.com, tconnors@astro.swin.edu.au, maxk@qualcomm.com, > gregory.haskins@gmail.com, pavel@suse.cz > > It utterly messed up the addressing mode of my reply here and i had to > edit the raw email headers manually to fix it up ;-)
OOPS! My bad mutt config! I have tried to fix this. Hopefully this will not cause trouble anymore.
Thanks, Vaidy
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