diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 43 | ||||
| -rw-r--r-- | arch/i386/kernel/smpboot.c | 12 | ||||
| -rw-r--r-- | arch/ia64/kernel/setup.c | 6 | ||||
| -rw-r--r-- | arch/mips/kernel/smp.c | 11 | ||||
| -rw-r--r-- | arch/sparc/kernel/smp.c | 10 | ||||
| -rw-r--r-- | arch/sparc64/kernel/smp.c | 27 | ||||
| -rw-r--r-- | include/linux/sched.h | 6 | ||||
| -rw-r--r-- | kernel/sched.c | 481 |
8 files changed, 0 insertions, 596 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index af50f9b..4d880b3 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1014,49 +1014,6 @@ and is between 256 and 4096 characters. It is defined in the file mga= [HW,DRM] - migration_cost= - [KNL,SMP] debug: override scheduler migration costs - Format: <level-1-usecs>,<level-2-usecs>,... - This debugging option can be used to override the - default scheduler migration cost matrix. The numbers - are indexed by 'CPU domain distance'. - E.g. migration_cost=1000,2000,3000 on an SMT NUMA - box will set up an intra-core migration cost of - 1 msec, an inter-core migration cost of 2 msecs, - and an inter-node migration cost of 3 msecs. - - WARNING: using the wrong values here can break - scheduler performance, so it's only for scheduler - development purposes, not production environments. - - migration_debug= - [KNL,SMP] migration cost auto-detect verbosity - Format=<0|1|2> - If a system's migration matrix reported at bootup - seems erroneous then this option can be used to - increase verbosity of the detection process. - We default to 0 (no extra messages), 1 will print - some more information, and 2 will be really - verbose (probably only useful if you also have a - serial console attached to the system). - - migration_factor= - [KNL,SMP] multiply/divide migration costs by a factor - Format=<percent> - This debug option can be used to proportionally - increase or decrease the auto-detected migration - costs for all entries of the migration matrix. - E.g. migration_factor=150 will increase migration - costs by 50%. (and thus the scheduler will be less - eager migrating cache-hot tasks) - migration_factor=80 will decrease migration costs - by 20%. (thus the scheduler will be more eager to - migrate tasks) - - WARNING: using the wrong values here can break - scheduler performance, so it's only for scheduler - development purposes, not production environments. - mousedev.tap_time= [MOUSE] Maximum time between finger touching and leaving touchpad surface for touch to be considered diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c index 88baed1..0b29545 100644 --- a/arch/i386/kernel/smpboot.c +++ b/arch/i386/kernel/smpboot.c @@ -941,17 +941,6 @@ exit: } #endif -static void smp_tune_scheduling(void) -{ - if (cpu_khz) { - /* cache size in kB */ - long cachesize = boot_cpu_data.x86_cache_size; - - if (cachesize > 0) - max_cache_size = cachesize * 1024; - } -} - /* * Cycle through the processors sending APIC IPIs to boot each. */ @@ -980,7 +969,6 @@ static void __init smp_boot_cpus(unsigned int max_cpus) x86_cpu_to_apicid[0] = boot_cpu_physical_apicid; current_thread_info()->cpu = 0; - smp_tune_scheduling(); set_cpu_sibling_map(0); diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c index eaa6a24..188fb73 100644 --- a/arch/ia64/kernel/setup.c +++ b/arch/ia64/kernel/setup.c @@ -805,7 +805,6 @@ static void __cpuinit get_max_cacheline_size (void) { unsigned long line_size, max = 1; - unsigned int cache_size = 0; u64 l, levels, unique_caches; pal_cache_config_info_t cci; s64 status; @@ -835,8 +834,6 @@ get_max_cacheline_size (void) line_size = 1 << cci.pcci_line_size; if (line_size > max) max = line_size; - if (cache_size < cci.pcci_cache_size) - cache_size = cci.pcci_cache_size; if (!cci.pcci_unified) { status = ia64_pal_cache_config_info(l, /* cache_type (instruction)= */ 1, @@ -853,9 +850,6 @@ get_max_cacheline_size (void) ia64_i_cache_stride_shift = cci.pcci_stride; } out: -#ifdef CONFIG_SMP - max_cache_size = max(max_cache_size, cache_size); -#endif if (max > ia64_max_cacheline_size) ia64_max_cacheline_size = max; } diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c index 67edfa7..a1b017f 100644 --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -51,16 +51,6 @@ int __cpu_logical_map[NR_CPUS]; /* Map logical to physical */ EXPORT_SYMBOL(phys_cpu_present_map); EXPORT_SYMBOL(cpu_online_map); -/* This happens early in bootup, can't really do it better */ -static void smp_tune_scheduling (void) -{ - struct cache_desc *cd = ¤t_cpu_data.scache; - unsigned long cachesize = cd->linesz * cd->sets * cd->ways; - - if (cachesize > max_cache_size) - max_cache_size = cachesize; -} - extern void __init calibrate_delay(void); extern ATTRIB_NORET void cpu_idle(void); @@ -228,7 +218,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) { init_new_context(current, &init_mm); current_thread_info()->cpu = 0; - smp_tune_scheduling(); plat_prepare_cpus(max_cpus); #ifndef CONFIG_HOTPLUG_CPU cpu_present_map = cpu_possible_map; diff --git a/arch/sparc/kernel/smp.c b/arch/sparc/kernel/smp.c index 4d9ad590..4fea3ac 100644 --- a/arch/sparc/kernel/smp.c +++ b/arch/sparc/kernel/smp.c @@ -68,16 +68,6 @@ void __cpuinit smp_store_cpu_info(int id) cpu_data(id).prom_node = cpu_node; cpu_data(id).mid = cpu_get_hwmid(cpu_node); - /* this is required to tune the scheduler correctly */ - /* is it possible to have CPUs with different cache sizes? */ - if (id == boot_cpu_id) { - int cache_line,cache_nlines; - cache_line = 0x20; - cache_line = prom_getintdefault(cpu_node, "ecache-line-size", cache_line); - cache_nlines = 0x8000; - cache_nlines = prom_getintdefault(cpu_node, "ecache-nlines", cache_nlines); - max_cache_size = cache_line * cache_nlines; - } if (cpu_data(id).mid < 0) panic("No MID found for CPU%d at node 0x%08d", id, cpu_node); } diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c index 4dcd7d0..40e40f9 100644 --- a/arch/sparc64/kernel/smp.c +++ b/arch/sparc64/kernel/smp.c @@ -1163,32 +1163,6 @@ int setup_profiling_timer(unsigned int multiplier) return -EINVAL; } -static void __init smp_tune_scheduling(void) -{ - unsigned int smallest = ~0U; - int i; - - for (i = 0; i < NR_CPUS; i++) { - unsigned int val = cpu_data(i).ecache_size; - - if (val && val < smallest) - smallest = val; - } - - /* Any value less than 256K is nonsense. */ - if (smallest < (256U * 1024U)) - smallest = 256 * 1024; - - max_cache_size = smallest; - - if (smallest < 1U * 1024U * 1024U) - printk(KERN_INFO "Using max_cache_size of %uKB\n", - smallest / 1024U); - else - printk(KERN_INFO "Using max_cache_size of %uMB\n", - smallest / 1024U / 1024U); -} - /* Constrain the number of cpus to max_cpus. */ void __init smp_prepare_cpus(unsigned int max_cpus) { @@ -1206,7 +1180,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) } cpu_data(boot_cpu_id).udelay_val = loops_per_jiffy; - smp_tune_scheduling(); } void __devinit smp_prepare_boot_cpu(void) diff --git a/include/linux/sched.h b/include/linux/sched.h index 7e74262..8764cda 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -754,12 +754,6 @@ struct sched_domain { extern int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2); -/* - * Maximum cache size the migration-costs auto-tuning code will - * search from: - */ -extern unsigned int max_cache_size; - #endif /* CONFIG_SMP */ diff --git a/kernel/sched.c b/kernel/sched.c index ac054d9..46b23f0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5797,483 +5797,6 @@ init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, #define SD_NODES_PER_DOMAIN 16 -/* - * Self-tuning task migration cost measurement between source and target CPUs. - * - * This is done by measuring the cost of manipulating buffers of varying - * sizes. For a given buffer-size here are the steps that are taken: - * - * 1) the source CPU reads+dirties a shared buffer - * 2) the target CPU reads+dirties the same shared buffer - * - * We measure how long they take, in the following 4 scenarios: - * - * - source: CPU1, target: CPU2 | cost1 - * - source: CPU2, target: CPU1 | cost2 - * - source: CPU1, target: CPU1 | cost3 - * - source: CPU2, target: CPU2 | cost4 - * - * We then calculate the cost3+cost4-cost1-cost2 difference - this is - * the cost of migration. - * - * We then start off from a small buffer-size and iterate up to larger - * buffer sizes, in 5% steps - measuring each buffer-size separately, and - * doing a maximum search for the cost. (The maximum cost for a migration - * normally occurs when the working set size is around the effective cache - * size.) - */ -#define SEARCH_SCOPE 2 -#define MIN_CACHE_SIZE (64*1024U) -#define DEFAULT_CACHE_SIZE (5*1024*1024U) -#define ITERATIONS 1 -#define SIZE_THRESH 130 -#define COST_THRESH 130 - -/* - * The migration cost is a function of 'domain distance'. Domain - * distance is the number of steps a CPU has to iterate down its - * domain tree to share a domain with the other CPU. The farther - * two CPUs are from each other, the larger the distance gets. - * - * Note that we use the distance only to cache measurement results, - * the distance value is not used numerically otherwise. When two - * CPUs have the same distance it is assumed that the migration - * cost is the same. (this is a simplification but quite practical) - */ -#define MAX_DOMAIN_DISTANCE 32 - -static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] = - { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = -/* - * Architectures may override the migration cost and thus avoid - * boot-time calibration. Unit is nanoseconds. Mostly useful for - * virtualized hardware: - */ -#ifdef CONFIG_DEFAULT_MIGRATION_COST - CONFIG_DEFAULT_MIGRATION_COST -#else - -1LL -#endif -}; - -/* - * Allow override of migration cost - in units of microseconds. - * E.g. migration_cost=1000,2000,3000 will set up a level-1 cost - * of 1 msec, level-2 cost of 2 msecs and level3 cost of 3 msecs: - */ -static int __init migration_cost_setup(char *str) -{ - int ints[MAX_DOMAIN_DISTANCE+1], i; - - str = get_options(str, ARRAY_SIZE(ints), ints); - - printk("#ints: %d\n", ints[0]); - for (i = 1; i <= ints[0]; i++) { - migration_cost[i-1] = (unsigned long long)ints[i]*1000; - printk("migration_cost[%d]: %Ld\n", i-1, migration_cost[i-1]); - } - return 1; -} - -__setup ("migration_cost=", migration_cost_setup); - -/* - * Global multiplier (divisor) for migration-cutoff values, - * in percentiles. E.g. use a value of 150 to get 1.5 times - * longer cache-hot cutoff times. - * - * (We scale it from 100 to 128 to long long handling easier.) - */ - -#define MIGRATION_FACTOR_SCALE 128 - -static unsigned int migration_factor = MIGRATION_FACTOR_SCALE; - -static int __init setup_migration_factor(char *str) -{ - get_option(&str, &migration_factor); - migration_factor = migration_factor * MIGRATION_FACTOR_SCALE / 100; - return 1; -} - -__setup("migration_factor=", setup_migration_factor); - -/* - * Estimated distance of two CPUs, measured via the number of domains - * we have to pass for the two CPUs to be in the same span: - */ -static unsigned long domain_distance(int cpu1, int cpu2) -{ - unsigned long distance = 0; - struct sched_domain *sd; - - for_each_domain(cpu1, sd) { - WARN_ON(!cpu_isset(cpu1, sd->span)); - if (cpu_isset(cpu2, sd->span)) - return distance; - distance++; - } - if (distance >= MAX_DOMAIN_DISTANCE) { - WARN_ON(1); - distance = MAX_DOMAIN_DISTANCE-1; - } - - return distance; -} - -static unsigned int migration_debug; - -static int __init setup_migration_debug(char *str) -{ - get_option(&str, &migration_debug); - return 1; -} - -__setup("migration_debug=", setup_migration_debug); - -/* - * Maximum cache-size that the scheduler should try to measure. - * Architectures with larger caches should tune this up during - * bootup. Gets used in the domain-setup code (i.e. during SMP - * bootup). - */ -unsigned int max_cache_size; - -static int __init setup_max_cache_size(char *str) -{ - get_option(&str, &max_cache_size); - return 1; -} - -__setup("max_cache_size=", setup_max_cache_size); - -/* - * Dirty a big buffer in a hard-to-predict (for the L2 cache) way. This - * is the operation that is timed, so we try to generate unpredictable - * cachemisses that still end up filling the L2 cache: - */ -static void touch_cache(void *__cache, unsigned long __size) -{ - unsigned long size = __size / sizeof(long); - unsigned long chunk1 = size / 3; - unsigned long chunk2 = 2 * size / 3; - unsigned long *cache = __cache; - int i; - - for (i = 0; i < size/6; i += 8) { - switch (i % 6) { - case 0: cache[i]++; - case 1: cache[size-1-i]++; - case 2: cache[chunk1-i]++; - case 3: cache[chunk1+i]++; - case 4: cache[chunk2-i]++; - case 5: cache[chunk2+i]++; - } - } -} - -/* - * Measure the cache-cost of one task migration. Returns in units of nsec. - */ -static unsigned long long -measure_one(void *cache, unsigned long size, int source, int target) -{ - cpumask_t mask, saved_mask; - unsigned long long t0, t1, t2, t3, cost; - - saved_mask = current->cpus_allowed; - - /* - * Flush source caches to RAM and invalidate them: - */ - sched_cacheflush(); - - /* - * Migrate to the source CPU: - */ - mask = cpumask_of_cpu(source); - set_cpus_allowed(current, mask); - WARN_ON(smp_processor_id() != source); - - /* - * Dirty the working set: - */ - t0 = sched_clock(); - touch_cache(cache, size); - t1 = sched_clock(); - - /* - * Migrate to the target CPU, dirty the L2 cache and access - * the shared buffer. (which represents the working set - * of a migrated task.) - */ - mask = cpumask_of_cpu(target); - set_cpus_allowed(current, mask); - WARN_ON(smp_processor_id() != target); - - t2 = sched_clock(); - touch_cache(cache, size); - t3 = sched_clock(); - - cost = t1-t0 + t3-t2; - - if (migration_debug >= 2) - printk("[%d->%d]: %8Ld %8Ld %8Ld => %10Ld.\n", - source, target, t1-t0, t1-t0, t3-t2, cost); - /* - * Flush target caches to RAM and invalidate them: - */ - sched_cacheflush(); - - set_cpus_allowed(current, saved_mask); - - return cost; -} - -/* - * Measure a series of task migrations and return the average - * result. Since this code runs early during bootup the system - * is 'undisturbed' and the average latency makes sense. - * - * The algorithm in essence auto-detects the relevant cache-size, - * so it will properly detect different cachesizes for different - * cache-hierarchies, depending on how the CPUs are connected. - * - * Architectures can prime the upper limit of the search range via - * max_cache_size, otherwise the search range defaults to 20MB...64K. - */ -static unsigned long long -measure_cost(int cpu1, int cpu2, void *cache, unsigned int size) -{ - unsigned long long cost1, cost2; - int i; - - /* - * Measure the migration cost of 'size' bytes, over an - * average of 10 runs: - * - * (We perturb the cache size by a small (0..4k) - * value to compensate size/alignment related artifacts. - * We also subtract the cost of the operation done on - * the same CPU.) - */ - cost1 = 0; - - /* - * dry run, to make sure we start off cache-cold on cpu1, - * and to get any vmalloc pagefaults in advance: - */ - measure_one(cache, size, cpu1, cpu2); - for (i = 0; i < ITERATIONS; i++) - cost1 += measure_one(cache, size - i * 1024, cpu1, cpu2); - - measure_one(cache, size, cpu2, cpu1); - for (i = 0; i < ITERATIONS; i++) - cost1 += measure_one(cache, size - i * 1024, cpu2, cpu1); - - /* - * (We measure the non-migrating [cached] cost on both - * cpu1 and cpu2, to handle CPUs with different speeds) - */ - cost2 = 0; - - measure_one(cache, size, cpu1, cpu1); - for (i = 0; i < ITERATIONS; i++) - cost2 += measure_one(cache, size - i * 1024, cpu1, cpu1); - - measure_one(cache, size, cpu2, cpu2); - for (i = 0; i < ITERATIONS; i++) - cost2 += measure_one(cache, size - i * 1024, cpu2, cpu2); - - /* - * Get the per-iteration migration cost: - */ - do_div(cost1, 2 * ITERATIONS); - do_div(cost2, 2 * ITERATIONS); - - return cost1 - cost2; -} - -static unsigned long long measure_migration_cost(int cpu1, int cpu2) -{ - unsigned long long max_cost = 0, fluct = 0, avg_fluct = 0; - unsigned int max_size, size, size_found = 0; - long long cost = 0, prev_cost; - void *cache; - - /* - * Search from max_cache_size*5 down to 64K - the real relevant - * cachesize has to lie somewhere inbetween. - */ - if (max_cache_size) { - max_size = max(max_cache_size * SEARCH_SCOPE, MIN_CACHE_SIZE); - size = max(max_cache_size / SEARCH_SCOPE, MIN_CACHE_SIZE); - } else { - /* - * Since we have no estimation about the relevant - * search range - */ - max_size = DEFAULT_CACHE_SIZE * SEARCH_SCOPE; - size = MIN_CACHE_SIZE; - } - - if (!cpu_online(cpu1) || !cpu_online(cpu2)) { - printk("cpu %d and %d not both online!\n", cpu1, cpu2); - return 0; - } - - /* - * Allocate the working set: - */ - cache = vmalloc(max_size); - if (!cache) { - printk("could not vmalloc %d bytes for cache!\n", 2 * max_size); - return 1000000; /* return 1 msec on very small boxen */ - } - - while (size <= max_size) { - prev_cost = cost; - cost = measure_cost(cpu1, cpu2, cache, size); - - /* - * Update the max: - */ - if (cost > 0) { - if (max_cost < cost) { - max_cost = cost; - size_found = size; - } - } - /* - * Calculate average fluctuation, we use this to prevent - * noise from triggering an early break out of the loop: - */ - fluct = abs(cost - prev_cost); - avg_fluct = (avg_fluct + fluct)/2; - - if (migration_debug) - printk("-> [%d][%d][%7d] %3ld.%ld [%3ld.%ld] (%ld): " - "(%8Ld %8Ld)\n", - cpu1, cpu2, size, - (long)cost / 1000000, - ((long)cost / 100000) % 10, - (long)max_cost / 1000000, - ((long)max_cost / 100000) % 10, - domain_distance(cpu1, cpu2), - cost, avg_fluct); - - /* - * If we iterated at least 20% past the previous maximum, - * and the cost has dropped by more than 20% already, - * (taking fluctuations into account) then we assume to - * have found the maximum and break out of the loop early: - */ - if (size_found && (size*100 > size_found*SIZE_THRESH)) - if (cost+avg_fluct <= 0 || - max_cost*100 > (cost+avg_fluct)*COST_THRESH) { - - if (migration_debug) - printk("-> found max.\n"); - break; - } - /* - * Increase the cachesize in 10% steps: - */ - size = size * 10 / 9; - } - - if (migration_debug) - printk("[%d][%d] working set size found: %d, cost: %Ld\n", - cpu1, cpu2, size_found, max_cost); - - vfree(cache); - - /* - * A task is considered 'cache cold' if at least 2 times - * the worst-case cost of migration has passed. - * - * (this limit is only listened to if the load-balancing - * situation is 'nice' - if there is a large imbalance we - * ignore it for the sake of CPU utilization and - * processing fairness.) - */ - return 2 * max_cost * migration_factor / MIGRATION_FACTOR_SCALE; -} - -static void calibrate_migration_costs(const cpumask_t *cpu_map) -{ - int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = raw_smp_processor_id(); - unsigned long j0, j1, distance, max_distance = 0; - struct sched_domain *sd; - - j0 = jiffies; - - /* - * First pass - calculate the cacheflush times: - */ - for_each_cpu_mask(cpu1, *cpu_map) { - for_each_cpu_mask(cpu2, *cpu_map) { - if (cpu1 == cpu2) - continue; - distance = domain_distance(cpu1, cpu2); - max_distance = max(max_distance, distance); - /* - * No result cached yet? - */ - if (migration_cost[distance] == -1LL) - migration_cost[distance] = - measure_migration_cost(cpu1, cpu2); - } - } - /* - * Second pass - update the sched domain hierarchy with - * the new cache-hot-time estimations: - */ - for_each_cpu_mask(cpu, *cpu_map) { - distance = 0; - for_each_domain(cpu, sd) { - sd->cache_hot_time = migration_cost[distance]; - distance++; - } - } - /* - * Print the matrix: - */ - if (migration_debug) - printk("migration: max_cache_size: %d, cpu: %d MHz:\n", - max_cache_size, -#ifdef CONFIG_X86 - cpu_khz/1000 -#else - -1 -#endif - ); - if (system_state == SYSTEM_BOOTING && num_online_cpus() > 1) { - printk("migration_cost="); - for (distance = 0; distance <= max_distance; distance++) { - if (distance) - printk(","); - printk("%ld", (long)migration_cost[distance] / 1000); - } - printk("\n"); - } - j1 = jiffies; - if (migration_debug) - printk("migration: %ld seconds\n", (j1-j0) / HZ); - - /* - * Move back to the original CPU. NUMA-Q gets confused - * if we migrate to another quad during bootup. - */ - if (raw_smp_processor_id() != orig_cpu) { - cpumask_t mask = cpumask_of_cpu(orig_cpu), - saved_mask = current->cpus_allowed; - - set_cpus_allowed(current, mask); - set_cpus_allowed(current, saved_mask); - } -} - #ifdef CONFIG_NUMA /** @@ -6803,10 +6326,6 @@ static int build_sched_domains(const cpumask_t *cpu_map) #endif cpu_attach_domain(sd, i); } - /* - * Tune cache-hot values: - */ - calibrate_migration_costs(cpu_map); return 0; |
