From 5022b8ac608f8b80b042a8041fe2738c4b9ea8cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 25 Jun 2020 17:05:58 -0700 Subject: scftorture: Implement weighted primitive selection This commit uses the scftorture.weight* kernel parameters to randomly chooses between smp_call_function_single(), smp_call_function_many(), and smp_call_function(). For each variant, it also randomly chooses whether to invoke it synchronously (wait=1) or asynchronously (wait=0). The percentage weighting for each option are dumped to the console log (search for "scf_sel_dump"). This accumulates statistics, which a later commit will dump out at the end of the run. Signed-off-by: Paul E. McKenney --- kernel/scftorture.c | 182 ++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 155 insertions(+), 27 deletions(-) (limited to 'kernel/scftorture.c') diff --git a/kernel/scftorture.c b/kernel/scftorture.c index 44f1e49ba6e9..5f1984522ae4 100644 --- a/kernel/scftorture.c +++ b/kernel/scftorture.c @@ -64,8 +64,8 @@ torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU torture_param(int, verbose, 0, "Enable verbose debugging printk()s"); torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations."); torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations."); -torture_param(int, weight_mult, -1, "Testing weight for multi-CPU no-wait operations."); -torture_param(int, weight_mult_wait, -1, "Testing weight for multi-CPU operations."); +torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations."); +torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations."); torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations."); torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations."); @@ -83,9 +83,11 @@ struct scf_statistics { struct task_struct *task; int cpu; long long n_single; + long long n_single_ofl; long long n_single_wait; - long long n_multi; - long long n_multi_wait; + long long n_single_wait_ofl; + long long n_many; + long long n_many_wait; long long n_all; long long n_all_wait; }; @@ -94,6 +96,27 @@ static struct scf_statistics *scf_stats_p; static struct task_struct *scf_torture_stats_task; static DEFINE_PER_CPU(long long, scf_invoked_count); +// Data for random primitive selection +#define SCF_PRIM_SINGLE 0 +#define SCF_PRIM_MANY 1 +#define SCF_PRIM_ALL 2 +#define SCF_NPRIMS (2 * 3) // Need wait and no-wait versions of each. + +static char *scf_prim_name[] = { + "smp_call_function_single", + "smp_call_function_many", + "smp_call_function", +}; + +struct scf_selector { + unsigned long scfs_weight; + int scfs_prim; + bool scfs_wait; +}; +static struct scf_selector scf_sel_array[SCF_NPRIMS]; +static int scf_sel_array_len; +static unsigned long scf_sel_totweight; + // Use to wait for all threads to start. static atomic_t n_started; static atomic_t n_errs; @@ -131,6 +154,57 @@ scf_torture_stats(void *arg) return 0; } +// Add a primitive to the scf_sel_array[]. +static void scf_sel_add(unsigned long weight, int prim, bool wait) +{ + struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len]; + + // If no weight, if array would overflow, if computing three-place + // percentages would overflow, or if the scf_prim_name[] array would + // overflow, don't bother. In the last three two cases, complain. + if (!weight || + WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) || + WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) || + WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name))) + return; + scf_sel_totweight += weight; + scfsp->scfs_weight = scf_sel_totweight; + scfsp->scfs_prim = prim; + scfsp->scfs_wait = wait; + scf_sel_array_len++; +} + +// Dump out weighting percentages for scf_prim_name[] array. +static void scf_sel_dump(void) +{ + int i; + unsigned long oldw = 0; + struct scf_selector *scfsp; + unsigned long w; + + for (i = 0; i < scf_sel_array_len; i++) { + scfsp = &scf_sel_array[i]; + w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight; + pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000, + scf_prim_name[scfsp->scfs_prim], + scfsp->scfs_wait ? "wait" : "nowait"); + oldw = scfsp->scfs_weight; + } +} + +// Randomly pick a primitive and wait/nowait, based on weightings. +static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp) +{ + int i; + unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1); + + for (i = 0; i < scf_sel_array_len; i++) + if (scf_sel_array[i].scfs_weight >= w) + return &scf_sel_array[i]; + WARN_ON_ONCE(1); + return &scf_sel_array[0]; +} + // Update statistics and occasionally burn up mass quantities of CPU time, // if told to do so via scftorture.longwait. Otherwise, occasionally burn // a little bit. @@ -162,15 +236,55 @@ static void scf_handler(void *unused) } } +// As above, but check for correct CPU. +static void scf_handler_1(void *me) +{ + if (WARN_ON_ONCE(smp_processor_id() != (uintptr_t)me)) + atomic_inc(&n_errs); + scf_handler(NULL); +} + // Randomly do an smp_call_function*() invocation. -static void scftorture_invoke_one(struct scf_statistics *scfp,struct torture_random_state *trsp) +static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp) { + uintptr_t cpu; + int ret; + struct scf_selector *scfsp = scf_sel_rand(trsp); + if (use_cpus_read_lock) cpus_read_lock(); else preempt_disable(); - scfp->n_all++; - smp_call_function(scf_handler, NULL, 0); + switch (scfsp->scfs_prim) { + case SCF_PRIM_SINGLE: + cpu = torture_random(trsp) % nr_cpu_ids; + if (scfsp->scfs_wait) + scfp->n_single_wait++; + else + scfp->n_single++; + ret = smp_call_function_single(cpu, scf_handler_1, (void *)cpu, scfsp->scfs_wait); + if (ret) { + if (scfsp->scfs_wait) + scfp->n_single_wait_ofl++; + else + scfp->n_single_ofl++; + } + break; + case SCF_PRIM_MANY: + if (scfsp->scfs_wait) + scfp->n_many_wait++; + else + scfp->n_many++; + smp_call_function_many(cpu_online_mask, scf_handler, NULL, scfsp->scfs_wait); + break; + case SCF_PRIM_ALL: + if (scfsp->scfs_wait) + scfp->n_all_wait++; + else + scfp->n_all++; + smp_call_function(scf_handler, NULL, scfsp->scfs_wait); + break; + } if (use_cpus_read_lock) cpus_read_unlock(); else @@ -222,8 +336,8 @@ static void scftorture_print_module_parms(const char *tag) { pr_alert(SCFTORT_FLAG - "--- %s: verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter_cpus=%d use_cpus_read_lock=%d, weight_single=%d, weight_single_wait=%d, weight_mult=%d, weight_mult_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag, - verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter_cpus, use_cpus_read_lock, weight_single, weight_single_wait, weight_mult, weight_mult_wait, weight_all, weight_all_wait); + "--- %s: verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter_cpus=%d use_cpus_read_lock=%d, weight_single=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag, + verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter_cpus, use_cpus_read_lock, weight_single, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait); } static void scf_cleanup_handler(void *unused) @@ -264,6 +378,12 @@ static int __init scf_torture_init(void) { long i; int firsterr = 0; + unsigned long weight_single1 = weight_single; + unsigned long weight_single_wait1 = weight_single_wait; + unsigned long weight_many1 = weight_many; + unsigned long weight_many_wait1 = weight_many_wait; + unsigned long weight_all1 = weight_all; + unsigned long weight_all_wait1 = weight_all_wait; if (!torture_init_begin(SCFTORT_STRING, verbose)) return -EBUSY; @@ -271,34 +391,42 @@ static int __init scf_torture_init(void) scftorture_print_module_parms("Start of test"); if (weight_single == -1 && weight_single_wait == -1 && - weight_mult == -1 && weight_mult_wait == -1 && + weight_many == -1 && weight_many_wait == -1 && weight_all == -1 && weight_all_wait == -1) { - weight_single = 1; - weight_single_wait = 1; - weight_mult = 1; - weight_mult_wait = 1; - weight_all = 1; - weight_all_wait = 1; + weight_single1 = 2 * nr_cpu_ids; + weight_single_wait1 = 2 * nr_cpu_ids; + weight_many1 = 2; + weight_many_wait1 = 2; + weight_all1 = 1; + weight_all_wait1 = 1; } else { if (weight_single == -1) - weight_single = 0; + weight_single1 = 0; if (weight_single_wait == -1) - weight_single_wait = 0; - if (weight_mult == -1) - weight_mult = 0; - if (weight_mult_wait == -1) - weight_mult_wait = 0; + weight_single_wait1 = 0; + if (weight_many == -1) + weight_many1 = 0; + if (weight_many_wait == -1) + weight_many_wait1 = 0; if (weight_all == -1) - weight_all = 0; + weight_all1 = 0; if (weight_all_wait == -1) - weight_all_wait = 0; + weight_all_wait1 = 0; } - if (weight_single == 0 && weight_single_wait == 0 && - weight_mult == 0 && weight_mult_wait == 0 && - weight_all == 0 && weight_all_wait == 0) { + if (weight_single1 == 0 && weight_single_wait1 == 0 && + weight_many1 == 0 && weight_many_wait1 == 0 && + weight_all1 == 0 && weight_all_wait1 == 0) { + VERBOSE_SCFTORTOUT_ERRSTRING("all zero weights makes no sense"); firsterr = -EINVAL; goto unwind; } + scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false); + scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true); + scf_sel_add(weight_many1, SCF_PRIM_MANY, false); + scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true); + scf_sel_add(weight_all1, SCF_PRIM_ALL, false); + scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true); + scf_sel_dump(); if (onoff_interval > 0) { firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL); -- cgit