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X-Received-From: 2a00:1450:400c:c09::241 Subject: [Qemu-devel] [PULL 22/69] rcutorture: remove synchronize_rcu from readers X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZohoMail: RDKM_2 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This gives much worse numbers for readers, especially if synchronize_rcu is made more expensive as is the case with --enable-membarrier. Before: $ tests/rcutorture 10 stress 10 n_reads: 98304 n_updates: 529 n_mberror: 0 rcu_stress_count: 98302 2 0 0 0 0 0 0 0 0 0 After: $ tests/rcutorture 10 stress 10 n_reads: 165158482 n_updates: 429 n_mberror: 0 rcu_stress_count: 165154364 4118 0 0 0 0 0 0 0 0 0 Signed-off-by: Paolo Bonzini --- tests/rcutorture.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/tests/rcutorture.c b/tests/rcutorture.c index 4002ecf123..49311c82ea 100644 --- a/tests/rcutorture.c +++ b/tests/rcutorture.c @@ -238,7 +238,6 @@ long long rcu_stress_count[RCU_STRESS_PIPE_LEN + 1]; static void *rcu_read_stress_test(void *arg) { int i; - int itercnt =3D 0; struct rcu_stress *p; int pc; long long n_reads_local =3D 0; @@ -269,9 +268,6 @@ static void *rcu_read_stress_test(void *arg) } rcu_stress_local[pc]++; n_reads_local++; - if ((++itercnt % 0x1000) =3D=3D 0) { - synchronize_rcu(); - } } qemu_mutex_lock(&counts_mutex); n_reads +=3D n_reads_local; --=20 2.14.3