From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 08/30] refperf: Convert nreaders to a module parameter
Date: Mon, 22 Jun 2020 17:29:51 -0700 [thread overview]
Message-ID: <20200623003013.26252-8-paulmck@kernel.org> (raw)
In-Reply-To: <20200623002941.GA26089@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
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>
---
kernel/rcu/refperf.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/kernel/rcu/refperf.c b/kernel/rcu/refperf.c
index e991d48..020e55a 100644
--- a/kernel/rcu/refperf.c
+++ b/kernel/rcu/refperf.c
@@ -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) {
--
2.9.5
next prev parent reply other threads:[~2020-06-23 0:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 0:29 [PATCH tip/core/rcu 0/30] Add read-side scalability tests for v5.9 Paul E. McKenney
2020-06-23 0:29 ` [PATCH tip/core/rcu 01/30] rcuperf: Remove useless while loops around wait_event paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 02/30] refperf: Add a test to measure performance of read-side synchronization paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 03/30] rcuperf: Add comments explaining the high reader overhead paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 04/30] torture: Add refperf to the rcutorture scripting paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 05/30] refperf: Add holdoff parameter to allow CPUs to come online paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 06/30] refperf: Hoist function-pointer calls out of the loop paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 07/30] refperf: Allow decimal nanoseconds paulmck
2020-06-23 0:29 ` paulmck [this message]
2020-06-23 0:29 ` [PATCH tip/core/rcu 09/30] refperf: Provide module parameter to specify number of experiments paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 10/30] refperf: Dynamically allocate experiment-summary output buffer paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 11/30] refperf: Dynamically allocate thread-summary " paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 12/30] refperf: Make functions static paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 13/30] refperf: Tune reader measurement interval paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 14/30] refperf: Convert reader_task structure's "start" field to int paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 15/30] refperf: More closely synchronize reader start times paulmck
2020-06-23 0:29 ` [PATCH tip/core/rcu 16/30] refperf: Add warmup and cooldown processing phases paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 17/30] refperf: Label experiment-number column "Runs" paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 18/30] refperf: Output per-experiment data points paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 19/30] refperf: Simplify initialization-time wakeup protocol paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 20/30] refperf: Add read-side delay module parameter paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 21/30] refperf: Adjust refperf.loop default value paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 22/30] doc: Document rcuperf's module parameters paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 23/30] refperf: Work around 64-bit division paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 24/30] refperf: Change readdelay module parameter to nanoseconds paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 25/30] refperf: Add test for RCU Tasks Trace readers paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 26/30] refperf: Add test for RCU Tasks readers paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 27/30] rcu-tasks: Fix synchronize_rcu_tasks_trace() header comment paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 28/30] refperf: Rename RCU_REF_PERF_TEST to RCU_REF_SCALE_TEST paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 29/30] refperf: Rename refperf.c to refscale.c and change internal names paulmck
2020-06-23 0:30 ` [PATCH tip/core/rcu 30/30] refscale: Change --torture type from refperf to refscale paulmck
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