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From: Sergey Matyukevich <geomatsi@gmail.com>
To: linux-snps-arc@lists.infradead.org
Cc: Vineet Gupta <vgupta@kernel.org>,
	Vladimir Isaev <isaev@synopsys.com>,
	Sergey Matyukevich <geomatsi@gmail.com>,
	Sergey Matyukevich <sergey.matyukevich@synopsys.com>
Subject: [RFC PATCH 05/13] ARCv2: memset: don't prefetch for len == 0 which happens a lot
Date: Tue, 22 Feb 2022 17:14:58 +0300	[thread overview]
Message-ID: <20220222141506.4003433-6-geomatsi@gmail.com> (raw)
In-Reply-To: <20220222141506.4003433-1-geomatsi@gmail.com>

From: Vineet Gupta <vgupta@kernel.org>

This avoids potential "bleeding" when size == 0 as cache line
would be dirtied (and possibly fetched from other cores) and
due to the same reasons more optimal too.

Signed-off-by: Vineet Gupta <vgupta@kernel.org>
---
 arch/arc/lib/memset-archs.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arc/lib/memset-archs.S b/arch/arc/lib/memset-archs.S
index d2e09fece5bc..d0a5cec4cdca 100644
--- a/arch/arc/lib/memset-archs.S
+++ b/arch/arc/lib/memset-archs.S
@@ -36,12 +36,13 @@
 #endif
 
 ENTRY_CFI(memset)
-	PREFETCHW_INSTR	r0, 0	; Prefetch the first write location
 	mov.f	0, r2
 ;;; if size is zero
 	jz.d	[blink]
 	mov	r3, r0		; don't clobber ret val
 
+	PREFETCHW_INSTR	r0, 0	; Prefetch the first write location
+
 ;;; if length < 8
 	brls.d.nt	r2, 8, .Lsmallchunk
 	mov.f	lp_count,r2
-- 
2.25.1


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  parent reply	other threads:[~2022-02-22 14:15 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-22 14:14 [RFC PATCH 00/13] ARC: handle the lack of ZOL support Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 01/13] ARC: uaccess: elide unaligned handling if hardware supports Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 02/13] ARC: Kconfig: introduce option to disable ZOL Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 03/13] ARC: uaccess: drop CC_OPTIMIZE_FOR_SIZE Sergey Matyukevich
2022-02-22 14:14 ` [RFC PATCH 04/13] ARC: uaccess: elide ZOL, use double load/stores Sergey Matyukevich
2022-02-22 14:14 ` Sergey Matyukevich [this message]
2022-02-22 14:14 ` [RFC PATCH 06/13] ARCv2: memset: elide unaligned handling if hardware supports Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 07/13] ARCv2: memset: rewrite using double load/stores Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 08/13] ARC: string: use generic C code if no ZOL support Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 09/13] ARC: delay: elide ZOL Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 10/13] ARC: checksum: " Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 11/13] ARC: head: " Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 12/13] ARC: build: inhibit ZOL generation by compiler Sergey Matyukevich
2022-02-22 14:15 ` [RFC PATCH 13/13] ARC: pt_regs: handle the case when ZOL is not supported Sergey Matyukevich
2022-02-28  2:09 ` [RFC PATCH 00/13] ARC: handle the lack of ZOL support Vineet Gupta
2022-03-03 19:22   ` Sergey Matyukevich
2022-03-23 10:09   ` [RFC PATCH 00/13] ARC: handle the lack of ZOL supporty Sergey Matyukevich

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