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refperf: Convert nreaders to a module parameter

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This commit converts nreaders to a module parameter, with the default
of -1 specifying the old behavior of using 75% of the readers.

Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2020-05-25 15:48:38 -07:00
parent 83b88c86da
commit 8fc28783a0
1 changed files with 11 additions and 5 deletions
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16
kernel/rcu/refperf.c
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@ -62,6 +62,12 @@ torture_param(int, holdoff, IS_BUILTIN(CONFIG_RCU_REF_PERF_TEST) ? 10 : 0,
"Holdoff time before test start (s)");
// Number of loops per experiment, all readers execute operations concurrently.
torture_param(long, loops, 10000000, "Number of loops per experiment.");
// Number of readers, with -1 defaulting to about 75% of the CPUs.
torture_param(int, nreaders, -1, "Number of readers, -1 for 75% of CPUs.");
// Number of runs.
torture_param(int, nruns, 30, "Number of experiments to run.");
// Reader delay in nanoseconds, 0 for no delay.
torture_param(int, readdelay, 0, "Read-side delay in nanoseconds.");
#ifdef MODULE
# define REFPERF_SHUTDOWN 0
@ -93,7 +99,6 @@ static wait_queue_head_t main_wq;
static int shutdown_start;
static struct reader_task *reader_tasks;
static int nreaders;
// Number of readers that are part of the current experiment.
static atomic_t nreaders_exp;
@ -411,8 +416,8 @@ static void
ref_perf_print_module_parms(struct ref_perf_ops *cur_ops, const char *tag)
{
pr_alert("%s" PERF_FLAG
"--- %s: verbose=%d shutdown=%d holdoff=%d loops=%ld\n", perf_type, tag,
verbose, shutdown, holdoff, loops);
"--- %s: verbose=%d shutdown=%d holdoff=%d loops=%ld nreaders=%d\n", perf_type, tag,
verbose, shutdown, holdoff, loops, nreaders);
}
static void
@ -501,8 +506,9 @@ ref_perf_init(void)
schedule_timeout_uninterruptible(1);
}
// Reader tasks (~75% of online CPUs).
nreaders = (num_online_cpus() >> 1) + (num_online_cpus() >> 2);
// Reader tasks (default to ~75% of online CPUs).
if (nreaders < 0)
nreaders = (num_online_cpus() >> 1) + (num_online_cpus() >> 2);
reader_tasks = kcalloc(nreaders, sizeof(reader_tasks[0]),
GFP_KERNEL);
if (!reader_tasks) {