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310 discussions

[PATCH RFCv2 0/8] EASv5.2: Performance Optimization

by Leo Yan

This patch series is to optimize performance and refine patches according to review comments. - Patch 0001 is add more chance to select previous CPU for cache hot; - In EAS code, the critical path is task waken up with function energy_aware_wake_cpu(); this function is purposed to select one possible target CPU with most energy saving. So it includes two underlying functionality: the first one is to select most power efficiency CPU for the task in one cluster, another is to migrate task from big core to little core if little core can meet performance requirement. For first functionality for selection most power efficiency CPU within cluster, EAS prefers to select a non-idle CPU so as result it packs tasks into one CPU as possible. This is not an optimal solution with two reasons: the first reason is this introduces long schedule latency after multiple tasks on the same rq; the second reason is it easily gets result as small tasks packing within one CPU with higher operating point. Finally this is the observed foremost issue if there have multiple tasks, neither power or performance can achieve optimal result. So patch 0002 is to solve this issue to try to select CPU if can keep CPU at lowest OPP as possible. - Current code has no mechanism to spread these tasks throughout the little cluster so tasks are packed on one CPU when CPU is not “over-utilized”. In this case, only one CPU is very busy but other CPUs in the same cluster are in idle state. Patch 0003 is to spread task in lowest schedule domain (in cluster level) after add a medium state named "half-utilized". This may a temperary solution, due this likely a better solution is to unify flag for "over-utilized". - In CFS, PELT signals take long time to increase to high value and decay to small value; on the other hand, EAS does not take account load_avg value (runnable time) but only focus on util_avg value (running time). So these issues are really dependent on fundamental signals. So hope have advanced method to accelerate PELT signals and dismiss the issue introduced by long runnable time. Patch 0004 we can take it as a temperary solution, likely we can use the big difference between load_avg and util_avg to change to use inflate value, also can use it to reflect runnable time. Patch 0004 also has side effects for misfit flag. If any CPU has “misfit” task on it, then EAS will set imbalance value as CPU capacity and migrate such load from little core to big core. So “misfit” is quite good for there have only one big task on the little CPU so the CPU cannot meet task’s performance requirement with function “task_fits_max(p, rq->cpu)”; but if there have two tasks on the little CPU, then the task’s utilization value just half of CPU capacity value so finally EAS considers CPU can meet task requirement. Patch 0004 can more easily to set true for misfit: rq->misfit_task = !task_fits_max(p, rq->cpu) - In function energy_aware_wake_cpu(), it is possible to directly migrate task from little core to big core, but the conditions are rigid: the condition 1 is CPU capacity cannot meet this task requirement; the condition 2 is source CPU is “over-utilized”. If the source CPU is not “over-utilized” for condition 2, then even little CPU cannot meet task requirement but EAS will compare CPU energy and as the end it still selects previous little CPU Patch 0005 is to add extra path to directly migrate task from little core to big core. - For very heavily workload with multi-threads, we observed the tasks are not migrated within big cluster, also tasks are hard to migrate from big cluster to little cluster even little cluster have idle CPUs are available to run. So need optimize EAS to handle this case likely to go back with CFS behaviour. Patch 0006 and 0008 are to fix this related issues. - SMP load balance may migrate small task onto big core, but usually at this time point we are only looking forward big tasks migration, finally this hurts both power and performance. So patch 0007 it will avoid small task to migrate to higher capacity CPU so it will give more chance to real big task migration to higher capacity CPU. Leo Yan (8): sched/fair: optimize to more chance to select previous CPU sched/fair: select CPU based on using lowest capacity sched/fair: support to spread task in lowest schedule domain sched/fair: use load metrics to replace util when have big difference sched/fair: add path to migrate to higher capacity CPU sched/fair: force idle balance when busiest group is overloaded sched/fair: avoid small task to migrate to higher capacity CPU sched/fair: set imbalance for too many tasks on rq kernel/sched/fair.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 173 insertions(+), 20 deletions(-) -- 1.9.1

10 years, 3 months

[PATCH RFC 0/8] EASv5.2: Optimize Performance

by Leo Yan

This patch series is to optimize performance. Patch 0001 is to optimize CPU selection flow so let task has more chance to stay on previous CPU. Patch 0002 actually is a big change for EAS's policy for CPU selection, it trys to select idle CPU as possible. From profiling result, 0002 have good effect that spread tasks out if there have many tasks are running at the meantime. Patches 0003~0004 are to optimize the scenario for single thread case. In this case, the thread has relative high utilization value, but the value cannot easily over tipping point. So patche 0004 try to set criteria to in some condition change to use load_avg rather than util_avg to boost the single thread. Patch 0005 is to optimize the flow for spreading tasks within big cluster. Patches 0006~0007 is to fix the signal for avg_load. Leo Yan (8): sched/fair: optimize to more chance to select previous CPU sched/fair: select idle CPU for waken up task sched/fair: add path to migrate to higher capacity CPU sched/fair: use load to replace util when have big difference sched/fair: spread tasks in cluster when over tipping point sched/fair: correct avg_load as CPU average load sched/fair: fix to calculate average load cross cluster sched/fair: set imbn to 1 for too many tasks on rq include/linux/sched.h | 1 + kernel/sched/fair.c | 93 +++++++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 84 insertions(+), 10 deletions(-) -- 1.9.1

10 years, 3 months

SchedTune: define payoff parameters for platform

by Leo Yan

Hi Patrick, [ + eas-dev ] Here have a common question for how to define schedTune threshold array for payoff. So basically I want check below questions: - When every CGroup has its own perf_boost_idx for PB region and perf_constrain_idx for PC region. So do you have suggestion or guideline to define these index? And for difference CGroup like "backgroud", "foreground" or "performance" every CGroup will have its dedicated index or the platform can share the same index value? - How to define the array value for "threshold_gains"? IIUC this array is platform dependency, but what's the reasonable method to generate this table? Here have some suggested testing for generating this table? Or my understanding is wrong so this array is fixed, then just need ajust perf_boost_idx/perf_constrain_idx for platform is enough? - So far we cannot set these payoff parameters (including perf_boost_idx/perf_constrain_idx and threshold_gains) from sysfs dynamically, so how we can initilizae these value for platform specific? Suppose now we can only set these value when kernel's init flow, right? Thanks, Leo Yan

10 years, 3 months

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10 years, 4 months

[PATCH v2] idlestat: Initialize CPU's idle state properly

by Leo Yan

In current code the CPU's idle state cpufreq_pstates::idle is initialized to '-1'; and until parse first "cpu_idle" event for the CPU then set CPU's idle state to '0' or '1' corresponding to active or idle. This will cause error for P-state's statistics: from the beginning to first "cpu_idle" event, during this period the CPU's idle state is '-1' so function cpu_change_pstate() will always think it's first update and finally abandon previous time. This will introduce very big error if the CPU is always running and never run into idle state. So this patch is to fix this issue by initialize CPU's corresponding C-state and P-state: - Firstly gather every CPU's starting frequency and time stamp; - Then gather CPU's idle state according to first cpu_idle log: If the CPU first cpu_idle state is '-1', that means from the beginning the CPU is stayed on idle state; If the CPU first cpu_idle state is other value, means the CPU is active. - With these info, finally initialize every CPU's C-state and P-state before analyse trace logs. Here should note one thing is: when CPU is idle at beginning, we don't know exact idle state, so just assume CPU is in idle state 0; but this will not impact too much for statistics, due usually idlestat will wakeup all CPUs at the beginning. So it will introduce very small deviation. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> --- tracefile_idlestat.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) diff --git a/tracefile_idlestat.c b/tracefile_idlestat.c index 3430693..d0cd366 100644 --- a/tracefile_idlestat.c +++ b/tracefile_idlestat.c @@ -152,6 +152,127 @@ int load_text_data_line(char *buffer, struct cpuidle_datas *datas, char *format, return get_wakeup_irq(datas, buffer); } + +/** + * init_cpu_idle_state - Init CPU's idle state according to first cpu_idle log. + * For a specific cpu_idle event, its state is '-1' then that means from the + * beginning the CPU is stayed on idle state; Otherwise means the CPU is active. + * So initilize per-CPU idle flag to get more accurate time. + * + * @datas: structure for P-state and C-state's statistics + * @f: the file handle of the idlestat trace file + */ +void init_cpu_idle_state(struct cpuidle_datas *datas, FILE *f) +{ + char buffer[BUFSIZE]; + int state, cpu; + double time; + struct cpufreq_pstates *ps; + + unsigned long *cpu_start_idle; + int *cpu_start_freq; + double cpu_start_time; + + fseek(f, 0, SEEK_SET); + + cpu_start_freq = malloc(sizeof(int) * datas->nrcpus); + for (cpu = 0; cpu < datas->nrcpus; cpu++) + cpu_start_freq[cpu] = 0xdeadbeef; + + /* + * Find the start time stamp and the CPU's frequency at beginning; + * So we can use these info to add dummy info. + */ + while (fgets(buffer, BUFSIZE, f)) { + + if (strstr(buffer, "cpu_frequency")) { + if (sscanf(buffer, TRACE_FORMAT, &time, &state, &cpu) + != 3) { + fprintf(stderr, "warning: Unrecognized cpuidle " + "record. The result of analysis might " + "be wrong.\n"); + return; + } + } else + continue; + + if (cpu_start_freq[cpu] != 0xdeadbeef) + continue; + + if (cpu == 0) + cpu_start_time = time; + + cpu_start_freq[cpu] = state; + + break; + } + + /* After traverse file, reset offset */ + fseek(f, 0, SEEK_SET); + + /* + * Find the CPU's idle state at beginning + */ + cpu_start_idle = malloc(sizeof(long) * datas->nrcpus); + for (cpu = 0; cpu < datas->nrcpus; cpu++) + cpu_start_idle[cpu] = 0xdeadbeef; + + while (fgets(buffer, BUFSIZE, f)) { + + if (strstr(buffer, "cpu_idle")) { + if (sscanf(buffer, TRACE_FORMAT, &time, &state, &cpu) + != 3) { + fprintf(stderr, "warning: Unrecognized cpuidle " + "record. The result of analysis might " + "be wrong.\n"); + return; + } + } else + continue; + + /* CPU's state has been initialized, skip it */ + if (cpu_start_idle[cpu] != 0xdeadbeef) + continue; + + /* + * The CPU's first cpu_idle is '-1', means CPU is staying in + * idle state and exit from idle until first cpu_idle event. + * Otherwise, means the CPU is active at beginning. + */ + if (state == -1) + cpu_start_idle[cpu] = 0; + else + cpu_start_idle[cpu] = 4294967295; + } + + /* After traverse file, reset offset */ + fseek(f, 0, SEEK_SET); + + /* Initialize every CPU's cstate and pstate */ + for (cpu = 0; cpu < datas->nrcpus; cpu++) { + + ps = &(datas->pstates[cpu]); + + if (cpu_start_idle[cpu] == 0) { + /* + * CPU is idle at beginning, init cstate; + * + * here don't know exact idle state, so just assume CPU + * is in idle state 0; but this will not impace too much + * for statistics, due usually idlestat will wakeup all + * CPUs at the beginning. + */ + ps->idle = 1; + store_data(cpu_start_time, 0, cpu, datas); + } else { + /* CPU is busy at beginning, init pstate */ + ps->idle = 0; + cpu_change_pstate(datas, cpu, cpu_start_freq[cpu], + cpu_start_time); + } + } +} + void load_text_data_lines(FILE *f, char *buffer, struct cpuidle_datas *datas) { double begin = 0, end = 0; @@ -159,6 +280,8 @@ void load_text_data_lines(FILE *f, char *buffer, struct cpuidle_datas *datas) setup_topo_states(datas); + init_cpu_idle_state(datas, f); + do { if (load_text_data_line(buffer, datas, TRACE_FORMAT, &begin, &end, &start) != -1) { -- 1.9.1

10 years, 4 months

[PATCH v3] idlestat: Initialize CPU's idle state properly

by Leo Yan

In current code the CPU's idle state cpufreq_pstates::idle is initialized to '-1'; and until parse first "cpu_idle" event for the CPU then set CPU's idle state to '0' or '1' corresponding to active or idle. This will cause error for P-state's statistics: from the beginning to first "cpu_idle" event, during this period the CPU's idle state is '-1' so function cpu_change_pstate() will always think it's first update and finally abandon previous time. This will introduce very big error if the CPU is always running and never run into idle state. So this patch is to fix this issue by initialize CPU's corresponding C-state and P-state: - Firstly gather every CPU's starting frequency and time stamp; - Then gather CPU's idle state according to first cpu_idle log: If the CPU first cpu_idle state is '-1', that means from the beginning the CPU is stayed on idle state; If the CPU first cpu_idle state is other value, means the CPU is active. - With these info, finally initialize every CPU's C-state and P-state before analyse trace logs. Here should note one thing is: when CPU is idle at beginning, we don't know exact idle state, so just assume CPU is in idle state 0; but this will not impact too much for statistics, due usually idlestat will wakeup all CPUs at the beginning. So it will introduce very small deviation. Signed-off-by: Leo Yan <leo.yan(a)linaro.org> --- tracefile_idlestat.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) diff --git a/tracefile_idlestat.c b/tracefile_idlestat.c index 3430693..2674478 100644 --- a/tracefile_idlestat.c +++ b/tracefile_idlestat.c @@ -152,6 +152,153 @@ int load_text_data_line(char *buffer, struct cpuidle_datas *datas, char *format, return get_wakeup_irq(datas, buffer); } + +/** + * init_cpu_idle_state - Init CPU's idle state according to first cpu_idle log. + * For a specific cpu_idle event, its state is '-1' then that means from the + * beginning the CPU is stayed on idle state; Otherwise means the CPU is active. + * So initilize per-CPU idle flag to get more accurate time. + * + * @datas: structure for P-state and C-state's statistics + * @f: the file handle of the idlestat trace file + */ +int init_cpu_idle_state(struct cpuidle_datas *datas, FILE *f) +{ + char buffer[BUFSIZE]; + int state, cpu; + double time; + struct cpufreq_pstates *ps; + + unsigned long *cpu_start_idle; + int *cpu_start_freq; + double cpu_start_time; + + int ret; + + ret = fseek(f, 0, SEEK_SET); + if (ret < 0) { + fprintf(stderr, "failed to set the start file position\n"); + return ret; + } + + cpu_start_freq = malloc(sizeof(int) * datas->nrcpus); + if (!cpu_start_freq) { + fprintf(stderr, "failed to alloc for start frequency states\n"); + return -1; + } + + for (cpu = 0; cpu < datas->nrcpus; cpu++) + cpu_start_freq[cpu] = 0xdeadbeef; + + /* + * Find the start time stamp and the CPU's frequency at beginning; + * So we can use these info to add dummy info. + */ + while (fgets(buffer, BUFSIZE, f)) { + + if (strstr(buffer, "cpu_frequency")) { + if (sscanf(buffer, TRACE_FORMAT, &time, &state, &cpu) + != 3) { + fprintf(stderr, "warning: Unrecognized cpuidle " + "record. The result of analysis might " + "be wrong.\n"); + return -1; + } + } else + continue; + + if (cpu_start_freq[cpu] != 0xdeadbeef) + continue; + + if (cpu == 0) + cpu_start_time = time; + + cpu_start_freq[cpu] = state; + + break; + } + + /* After traverse file, reset offset */ + ret = fseek(f, 0, SEEK_SET); + if (ret < 0) { + fprintf(stderr, "failed to set the start file position\n"); + return ret; + } + + /* + * Find the CPU's idle state at beginning + */ + cpu_start_idle = malloc(sizeof(long) * datas->nrcpus); + if (!cpu_start_idle) { + fprintf(stderr, "failed to alloc for start idle states\n"); + return -1; + } + + for (cpu = 0; cpu < datas->nrcpus; cpu++) + cpu_start_idle[cpu] = 0xdeadbeef; + + while (fgets(buffer, BUFSIZE, f)) { + + if (strstr(buffer, "cpu_idle")) { + if (sscanf(buffer, TRACE_FORMAT, &time, &state, &cpu) + != 3) { + fprintf(stderr, "warning: Unrecognized cpuidle " + "record. The result of analysis might " + "be wrong.\n"); + return -1; + } + } else + continue; + + /* CPU's state has been initialized, skip it */ + if (cpu_start_idle[cpu] != 0xdeadbeef) + continue; + + /* + * The CPU's first cpu_idle is '-1', means CPU is staying in + * idle state and exit from idle until first cpu_idle event. + * Otherwise, means the CPU is active at beginning. + */ + if (state == -1) + cpu_start_idle[cpu] = 0; + else + cpu_start_idle[cpu] = 4294967295; + } + + /* After traverse file, reset offset */ + ret = fseek(f, 0, SEEK_SET); + if (ret < 0) { + fprintf(stderr, "failed to set the start file position\n"); + return ret; + } + + /* Initialize every CPU's cstate and pstate */ + for (cpu = 0; cpu < datas->nrcpus; cpu++) { + + ps = &(datas->pstates[cpu]); + + if (cpu_start_idle[cpu] == 0) { + /* + * CPU is idle at beginning, init cstate; + * + * here don't know exact idle state, so just assume CPU + * is in idle state 0; but this will not impace too much + * for statistics, due usually idlestat will wakeup all + * CPUs at the beginning. + */ + ps->idle = 1; + store_data(cpu_start_time, 0, cpu, datas); + } else { + /* CPU is busy at beginning, init pstate */ + ps->idle = 0; + cpu_change_pstate(datas, cpu, cpu_start_freq[cpu], + cpu_start_time); + } + } + + return 0; +} + void load_text_data_lines(FILE *f, char *buffer, struct cpuidle_datas *datas) { double begin = 0, end = 0; @@ -159,6 +306,11 @@ void load_text_data_lines(FILE *f, char *buffer, struct cpuidle_datas *datas) setup_topo_states(datas); + if (init_cpu_idle_state(datas, f) < 0) { + fprintf(stderr, "failed to initlized cpu states\n"); + exit(-1); + } + do { if (load_text_data_line(buffer, datas, TRACE_FORMAT, &begin, &end, &start) != -1) { -- 1.9.1

10 years, 4 months

by Zhifei Yang

subscribe IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.

10 years, 4 months

[PATCH] sched/tune: Fix building when CGROUPS not enable

by Jon Medhurst (Tixy)

If we enable CONFIG_SCHED_TUNE without CONFIG_CGROUPS we get the following errors: kernel/sched/fair.c: In function 'energy_diff_evaluate': kernel/sched/fair.c:4795:2: error: implicit declaration of function 'schedtune_normalize_energy' [-Werror=implicit-function-declaration] nrg_delta = schedtune_normalize_energy(eenv->nrg.diff); ^ kernel/sched/fair.c:4798:2: error: implicit declaration of function 'schedtune_accept_deltas' [-Werror=implicit-function-declaration] eenv->payoff = schedtune_accept_deltas( ^ Fix this by making sure the dummy version of these functions are defined if the real ones aren't. Signed-off-by: Jon Medhurst <tixy(a)linaro.org> --- This is another build fix for the 3.18 backport of EAS [1] but I'm not sure if the missing functions are actually meant to do something in the case when we have SCHED_TUNE without CGROUPS? [1] http://git.linaro.org/arm/eas/kernel.git/shortlog/refs/heads/linux-3.18-eas… kernel/sched/tune.h | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/kernel/sched/tune.h b/kernel/sched/tune.h index da1f7b2..3410a1d 100644 --- a/kernel/sched/tune.h +++ b/kernel/sched/tune.h @@ -1,6 +1,3 @@ - -#ifdef CONFIG_SCHED_TUNE - #ifdef CONFIG_CGROUP_SCHEDTUNE int schedtune_cpu_boost(int cpu); @@ -13,14 +10,7 @@ int schedtune_normalize_energy(int energy); int schedtune_accept_deltas(int nrg_delta, int cap_delta, struct task_struct *task); -#else /* CONFIG_CGROUP_SCHEDTUNE */ - -#define schedtune_enqueue_task(task, cpu) do { } while (0) -#define schedtune_dequeue_task(task, cpu) do { } while (0) - -#endif /* CONFIG_CGROUP_SCHEDTUNE */ - -#else /* CONFIG_SCHED_TUNE */ +#else #define schedtune_enqueue_task(task, cpu) do { } while (0) #define schedtune_dequeue_task(task, cpu) do { } while (0) @@ -28,4 +18,4 @@ int schedtune_accept_deltas(int nrg_delta, int cap_delta, #define schedtune_normalize_energy(energy) energy #define schedtune_accept_deltas(nrg_delta, cap_delta, task) nrg_delta -#endif /* CONFIG_SCHED_TUNE */ +#endif -- 2.1.4

10 years, 4 months

DEV, We could not deliver your parcel, #0000147338

by FedEx 2Day A.M.

Dear Dev, This is to confirm that one or more of your parcels has been shipped. You can review complete details of your order in the find attached. Regards, Francis Alexander, FedEx Station Agent.

10 years, 4 months

DEV, Problem with parcel shipping, ID:00536973

by FedEx International Ground

Dear Dev, We could not deliver your item. Shipment Label is attached to email. Sincerely, Jason Fischer, FedEx Operation Manager.

10 years, 4 months

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