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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 15/18] rcuperf: Measure memory footprint during kfree_rcu() test
Date: Fri, 14 Feb 2020 16:41:22 -0800
Message-ID: <20200215004125.16953-9-paulmck@kernel.org> (raw)
In-Reply-To: <20200215003634.GA16227@paulmck-ThinkPad-P72>

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

During changes to kfree_rcu() code, we often check the amount of free
memory.  As an alternative to checking this manually, this commit adds a
measurement in the test itself.  It measures four times during the test
for available memory, digitally filters these measurements to produce a
running average with a weight of 0.5, and compares this digitally filtered
value with the amount of available memory at the beginning of the test.

Something like the following is printed at the end of the run:

Total time taken by all kfree'ers: 6369738407 ns, loops: 10000, batches: 764, memory footprint: 216MB

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/rcuperf.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/rcuperf.c b/kernel/rcu/rcuperf.c
index da94b89..a4a8d09 100644
--- a/kernel/rcu/rcuperf.c
+++ b/kernel/rcu/rcuperf.c
@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/err.h>
@@ -611,6 +612,7 @@ kfree_perf_thread(void *arg)
 	long me = (long)arg;
 	struct kfree_obj *alloc_ptr;
 	u64 start_time, end_time;
+	long long mem_begin, mem_during = 0;
 
 	VERBOSE_PERFOUT_STRING("kfree_perf_thread task started");
 	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
@@ -626,6 +628,12 @@ kfree_perf_thread(void *arg)
 	}
 
 	do {
+		if (!mem_during) {
+			mem_during = mem_begin = si_mem_available();
+		} else if (loop % (kfree_loops / 4) == 0) {
+			mem_during = (mem_during + si_mem_available()) / 2;
+		}
+
 		for (i = 0; i < kfree_alloc_num; i++) {
 			alloc_ptr = kmalloc(sizeof(struct kfree_obj), GFP_KERNEL);
 			if (!alloc_ptr)
@@ -645,9 +653,11 @@ kfree_perf_thread(void *arg)
 		else
 			b_rcu_gp_test_finished = cur_ops->get_gp_seq();
 
-		pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld\n",
+		pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n",
 		       (unsigned long long)(end_time - start_time), kfree_loops,
-		       rcuperf_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started));
+		       rcuperf_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started),
+		       (mem_begin - mem_during) >> (20 - PAGE_SHIFT));
+
 		if (shutdown) {
 			smp_mb(); /* Assign before wake. */
 			wake_up(&shutdown_wq);
-- 
2.9.5


  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-15  0:36 [PATCH tip/core/rcu 0/18] Torture-test updates for v5.7 Paul E. McKenney
2020-02-15  0:36 ` [PATCH tip/core/rcu 01/18] rcutorture: Suppress forward-progress complaints during early boot paulmck
2020-02-15  0:36 ` [PATCH tip/core/rcu 02/18] torture: Make results-directory date format completion-friendly paulmck
2020-02-15  0:36 ` [PATCH tip/core/rcu 03/18] rcutorture: Refrain from callback flooding during boot paulmck
2020-02-15  0:36 ` [PATCH tip/core/rcu 04/18] torture: Forgive -EBUSY from boottime CPU-hotplug operations paulmck
2020-02-15  0:36 ` [PATCH tip/core/rcu 05/18] rcutorture: Allow boottime stall warnings to be suppressed paulmck
2020-02-15  0:36 ` [PATCH tip/core/rcu 06/18] rcutorture: Suppress boottime bad-sequence warnings paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 07/18] torture: Allow disabling of boottime CPU-hotplug torture operations paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 08/18] rcutorture: Add 100-CPU configuration paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 09/18] rcutorture: Summarize summary of build and run results paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 10/18] rcutorture: Make kvm-find-errors.sh abort on bad directory paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 11/18] rcutorture: Fix rcu_torture_one_read()/rcu_torture_writer() data race paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 12/18] rcutorture: Fix stray access to rcu_fwd_cb_nodelay paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 13/18] rcutorture: Add READ_ONCE() to rcu_torture_count and rcu_torture_batch paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 14/18] rcutorture: Annotation lockless accesses to rcu_torture_current paulmck
2020-02-15  0:41 ` paulmck [this message]
2020-02-15  0:41 ` [PATCH tip/core/rcu 16/18] rcutorture: Make rcu_torture_barrier_cbs() post from corresponding CPU paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 17/18] rcutorture: Manually clean up after rcu_barrier() failure paulmck
2020-02-15  0:41 ` [PATCH tip/core/rcu 18/18] rcutorture: Set KCSAN Kconfig options to detect more data races paulmck

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