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From: Alexander A Sverdlin <alexander.sverdlin@nokia.com>
To: Paul Burton <paul.burton@imgtec.com>, linux-mips@vger.kernel.org
Cc: Alexander Sverdlin <alexander.sverdlin@nokia.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 3/6] MIPS: Octeon: qspinlock: Flush write buffer
Date: Wed, 27 Jan 2021 21:36:24 +0100	[thread overview]
Message-ID: <20210127203627.47510-4-alexander.sverdlin@nokia.com> (raw)
In-Reply-To: <20210127203627.47510-1-alexander.sverdlin@nokia.com>

From: Alexander Sverdlin <alexander.sverdlin@nokia.com>

Flushing the write buffer brings aroung 10% performace on the tight
uncontended spinlock loops on Octeon. Refer to commit 500c2e1fdbcc
("MIPS: Optimize spinlocks.").

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
---
 arch/mips/include/asm/spinlock.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/mips/include/asm/spinlock.h b/arch/mips/include/asm/spinlock.h
index 8a88eb2..0a707f3 100644
--- a/arch/mips/include/asm/spinlock.h
+++ b/arch/mips/include/asm/spinlock.h
@@ -24,6 +24,9 @@ static inline void queued_spin_unlock(struct qspinlock *lock)
 	/* This could be optimised with ARCH_HAS_MMIOWB */
 	mmiowb();
 	smp_store_release(&lock->locked, 0);
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+	nudge_writes();
+#endif
 }
 
 #include <asm/qspinlock.h>
-- 
2.10.2


  parent reply	other threads:[~2021-01-27 20:37 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-27 20:36 [PATCH 0/6] MIPS: qspinlock: Try to reduce reduce the spinlock regression Alexander A Sverdlin
2021-01-27 20:36 ` [PATCH 1/6] MIPS: Octeon: Implement __smp_store_release() Alexander A Sverdlin
2021-01-27 22:32   ` Peter Zijlstra
2021-01-28  7:27     ` Alexander Sverdlin
2021-01-28 11:33       ` Peter Zijlstra
2021-01-28 11:52         ` Alexander Sverdlin
2021-01-28 14:57           ` Peter Zijlstra
2021-01-28 15:15             ` Peter Zijlstra
2021-01-28 12:09         ` Alexander Sverdlin
2021-01-28 15:04           ` Peter Zijlstra
2021-01-27 20:36 ` [PATCH 2/6] MIPS: Implement atomic_cmpxchg_relaxed() Alexander A Sverdlin
2021-01-27 20:36 ` Alexander A Sverdlin [this message]
2021-01-27 22:34   ` [PATCH 3/6] MIPS: Octeon: qspinlock: Flush write buffer Peter Zijlstra
2021-01-28  7:29     ` Alexander Sverdlin
2021-01-28 11:35       ` Peter Zijlstra
2021-01-28 12:13         ` Alexander Sverdlin
2021-01-28 15:26           ` Peter Zijlstra
2021-01-27 20:36 ` [PATCH 4/6] MIPS: Octeon: qspinlock: Exclude mmiowb() Alexander A Sverdlin
2021-01-27 22:35   ` Peter Zijlstra
2021-01-27 20:36 ` [PATCH 5/6] MIPS: Provide {atomic_}xchg_relaxed() Alexander A Sverdlin
2021-01-27 20:36 ` [PATCH 6/6] MIPS: cmpxchg: Use cmpxchg_local() for {cmp_}xchg_small() Alexander A Sverdlin
2021-01-27 22:37   ` Peter Zijlstra

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