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Commit 5022b8ac authored by Paul E. McKenney's avatar Paul E. McKenney
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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: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 80c9476e
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Showing with 155 additions and 27 deletions
kernel/scftorture.c
View file @ 5022b8ac
......@@ -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);
......
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