Hi, It seems that this is obsolete.. There is a call in 2.6.12.6 kernel (during fork), but not in the latest kernel. Please refer to: http://lxr.linux.no/linux+v2.6.12/kernel/sched.c <http://lxr.linux.no/linux+v2.6.12/kernel/sched.c>
On Wed, Dec 8, 2010 at 6:33 PM, lalit mohan tripathi < [email protected]> wrote: > On Wed, Dec 8, 2010 at 1:29 PM, Mulyadi Santosa > <[email protected]> wrote: > > Hi Lalit... > > > > On Wed, Dec 8, 2010 at 13:15, lalit mohan tripathi > > <[email protected]> wrote: > > > >> Thanks for your reply. The global timer interrupt is called > >> periodically at the HZ frequency (or as set for per-cpu local timers > >> in case of SMP). > >> Can you shed more light about what you mean by "timer interrupt is > reenabled"? > >> In my thinking timer interrupt (single-core: global timer interrupt, > >> SMP: local timer interrupt) would anyway run at regular interval > >> (unless preemption is disabled for brief moment). > > > > OK, since I am more or less as clueless as you are (can't find any > > exact code trace so far), so I'd just share my suspicion: > > > > As the comment says "this function (scheduler_tick) is also called > > when parent's time slice is recalculated", I highly suspect that at > > that "recalculation" stage, timer interrupt is disabled. Thus, > > scheduler_tick...for few moments is also skipped. > > > > Why I guess so? If recalculation happen and at the same time timer > > interrupt is still "running", quite likely one will disrupt other. The > > net result: time slice final value isn't as expected. > > > > Once the recalculation is done, timer interrupt should be re-enabled. > > Thus, at this point, scheduler tick...indirectly is also called. > > > > > > -- > > regards, > > > > Mulyadi Santosa > > Freelance Linux trainer and consultant > > > > blog: the-hydra.blogspot.com > > training: mulyaditraining.blogspot.com > > > Thanks for sharing your opinion. So, it means that the comment ("this > function (scheduler_tick) is also called > when parent's time slice is recalculated") is incorrect or has become > obsolete in new kernel codes (currently 2.6.30 ~ 2.6.36). > Can anybody confim about it? > > -- > To unsubscribe from this list: send an email with > "unsubscribe kernelnewbies" to [email protected] > Please read the FAQ at http://kernelnewbies.org/FAQ > > -- Regards, Himanshu
