在 2013-8-8,下午5:04,"ethan.zhao" <ethan.ker...@gmail.com> 写道:
> Kernel 3.11-rc1 +Peterz' patch+ Mike's patch, No C-states in BIOS, got the > same result as only Peter's patch. Typo 3.11-rc3 > Of course , No C states to enter, make sense. > [root@localhost ~]# time ./pip1m > > real 0m4.381s > user 0m0.099s > sys 0m2.784s > [root@localhost ~]# time ./pip1m > > real 0m4.436s > user 0m0.093s > sys 0m2.809s > [root@localhost ~]# > > Retest with C-states enabled in BIOS > [root@localhost ~]# time ./pip1m > > real 0m8.670s > user 0m0.203s > sys 0m5.459s > [root@localhost ~]# time ./pip1m > > real 0m8.489s > user 0m0.184s > sys 0m5.360s > [root@localhost ~]# > > So the result is Peter's patch working or Mike's ? Compared with default > 3.11-rc3 > result of test case 1 as following, looks great. > [root@localhost ~]# time ./pip1m > > real 0m10.683s > user 0m0.204s > sys 0m6.597s > [root@localhost ~]# time ./pip1m > > real 0m10.629s > user 0m0.185s > sys 0m6.546s > > So revert Mike's patch and retest, got > [root@localhost ~]# time ./pip1m > > real 0m8.606s > user 0m0.193s > sys 0m5.449s > [root@localhost ~]# time ./pip1m > > real 0m8.655s > user 0m0.198s > sys 0m5.519s > [root@localhost ~]# > > So, it's Peter's patch working……… > > The result of kernel 3.11-rc3 + Peter's patch + no rescheduling IPI and no > C-states in BIOS is : > [root@localhost ~]# time ./pip1m > > real 0m3.915s > user 0m0.088s > sys 0m2.487s > [root@localhost ~]# time ./pip1m > > real 0m3.929s > user 0m0.082s > sys 0m2.560s > [root@localhost ~]# time ./pip1m > > Got about 0.5 sec better than only Peter's patch, but it is strange, only no > rescheduling IPI almost got the > same result. > > > Thanks, > Ethan > > > 在 2013-8-8,下午12:31,ethan.zhao <ethan.ker...@gmail.com> 写道: >>>> >>>> sched: ratelimit nohz >>>> >>>> Entering nohz code on every micro-idle is too expensive to bear. >>>> >>>> Signed-off-by: Mike Galbraith <efa...@gmx.de> >>>> >>>> --- >>>> include/linux/sched.h | 5 +++++ >>>> kernel/sched/core.c | 5 +++++ >>>> kernel/time/tick-sched.c | 2 +- >>>> 3 files changed, 11 insertions(+), 1 deletion(-) >>>> >>>> --- a/include/linux/sched.h >>>> +++ b/include/linux/sched.h >>>> @@ -235,9 +235,14 @@ extern int runqueue_is_locked(int cpu); >>>> extern void nohz_balance_enter_idle(int cpu); >>>> extern void set_cpu_sd_state_idle(void); >>>> extern int get_nohz_timer_target(void); >>>> +extern int sched_needs_cpu(int cpu); >>>> #else >>>> static inline void nohz_balance_enter_idle(int cpu) { } >>>> static inline void set_cpu_sd_state_idle(void) { } >>>> +static inline int sched_needs_cpu(int cpu) >>>> +{ >>>> + return 0; >>>> +} >>>> #endif >>>> >>>> /* >>>> --- a/kernel/sched/core.c >>>> +++ b/kernel/sched/core.c >>>> @@ -650,6 +650,11 @@ static inline bool got_nohz_idle_kick(vo >>>> return false; >>>> } >>>> >>>> +int sched_needs_cpu(int cpu) >>>> +{ >>>> + return cpu_rq(cpu)->avg_idle < sysctl_sched_migration_cost; >>>> +} >>>> + >>>> #else /* CONFIG_NO_HZ_COMMON */ >>>> >>>> static inline bool got_nohz_idle_kick(void) >>>> --- a/kernel/time/tick-sched.c >>>> +++ b/kernel/time/tick-sched.c >>>> @@ -548,7 +548,7 @@ static ktime_t tick_nohz_stop_sched_tick >>>> time_delta = timekeeping_max_deferment(); >>>> } while (read_seqretry(&jiffies_lock, seq)); >>>> >>>> - if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || >>>> + if (sched_needs_cpu(cpu) || rcu_needs_cpu(cpu, &rcu_delta_jiffies) || >>>> arch_needs_cpu(cpu) || irq_work_needs_cpu()) { >>>> next_jiffies = last_jiffies + 1; >>>> delta_jiffies = 1; >>>> >>>> >>> >>> >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/