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From: Richard Palethorpe <rpalethorpe@suse.com>
To: ltp@lists.linux.it
Subject: [LTP] [PATCH v4 7/7] fzsync: Check processor affinity
Date: Tue, 13 Apr 2021 08:07:53 +0100	[thread overview]
Message-ID: <20210413070753.1691-8-rpalethorpe@suse.com> (raw)
In-Reply-To: <20210413070753.1691-1-rpalethorpe@suse.com>

It is useful for testing Fuzzy Sync itself to set the CPU affinity to
a single core. The current processes affinity does not effect
tst_ncpus(), but we can get the affinity separately.

Note that checking this still does not guarantee we will use yield
when restricted to only one core. We would have to periodically probe
which CPUs threads are running on until we detect more than one CPU.

Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
Acked-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Li Wang <liwang@redhat.com>
---
 include/tst_fuzzy_sync.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/tst_fuzzy_sync.h b/include/tst_fuzzy_sync.h
index 36a604e13..8f97bb8f6 100644
--- a/include/tst_fuzzy_sync.h
+++ b/include/tst_fuzzy_sync.h
@@ -61,7 +61,6 @@
 
 #include <math.h>
 #include <pthread.h>
-#include <sched.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <sys/time.h>
@@ -218,7 +217,9 @@ static void tst_fzsync_pair_init(struct tst_fzsync_pair *pair)
 	CHK(max_dev_ratio, 0, 1, 0.1);
 	CHK(exec_time_p, 0, 1, 0.5);
 	CHK(exec_loops, 20, INT_MAX, 3000000);
-	CHK(yield_in_wait, 0, 1, (tst_ncpus() <= 1));
+
+	if (tst_ncpus_available() <= 1)
+		pair->yield_in_wait = 1;
 }
 #undef CHK
 
-- 
2.30.2


      parent reply	other threads:[~2021-04-13  7:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-13  7:07 [LTP] [PATCH v4 0/7] Fuzzy Sync single core support and tests Richard Palethorpe
2021-04-13  7:07 ` [LTP] [PATCH v4 1/7] fzsync: Add self tests Richard Palethorpe
2021-04-13  8:34   ` Cyril Hrubis
2021-04-13  7:07 ` [LTP] [PATCH v4 2/7] fzsync: Reset delay bias Richard Palethorpe
2021-04-13  7:07 ` [LTP] [PATCH v4 3/7] fzsync: Correctly print positive lower delay range bound Richard Palethorpe
2021-04-13  7:07 ` [LTP] [PATCH v4 4/7] fzsync: Add sched_yield for single core machine Richard Palethorpe
2021-04-13  7:07 ` [LTP] [PATCH v4 5/7] fzsync: Move yield check out of loop and add yield to delay Richard Palethorpe
2021-04-13  7:07 ` [LTP] [PATCH v4 6/7] API: Add tst_ncpus_available Richard Palethorpe
2021-04-13  7:07 ` Richard Palethorpe [this message]

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