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* [PATCH] rt-tests: cyclictest: try not to share the same cpu with main thread
@ 2020-06-20  1:48 Yunfeng Ye
  2020-07-01 16:24 ` John Kacur
  0 siblings, 1 reply; 3+ messages in thread
From: Yunfeng Ye @ 2020-06-20  1:48 UTC (permalink / raw)
  To: williams, jkacur; +Cc: linux-rt-users, Shiyuan Hu, Hewenliang

The main thread will interfere with the test thread and try not to share
the same CPU with the main thread when the number of thread is less than
max_cpus.

Signed-off-by: yeyunfeng <yeyunfeng@huawei.com>
---
 src/cyclictest/cyclictest.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 989113fb3483..b3d72caa10ce 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -1080,7 +1080,8 @@ static int cpu_for_thread_sp(int thread_num, int max_cpus)
 		fatal("No allowable cpus to run on\n");
 	}

-	m = thread_num % num_cpus;
+	/* just don't try to share the same cpu with main thread */
+	m = (thread_num + 1) % num_cpus;

 	/* there are num_cpus bits set, we want position of m'th one */
 	for (i = 0, cpu = 0; i < max_cpus; i++) {
-- 
1.8.3.1


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2020-06-20  1:48 [PATCH] rt-tests: cyclictest: try not to share the same cpu with main thread Yunfeng Ye
2020-07-01 16:24 ` John Kacur
2020-07-02  1:45   ` Yunfeng Ye

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