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* [PATCH] arm64: optimize memcpy_{from,to}io() and memset_io()
@ 2014-07-30  6:28 Joonwoo Park
  2014-08-01  6:30 ` Joonwoo Park
  0 siblings, 1 reply; 12+ messages in thread
From: Joonwoo Park @ 2014-07-30  6:28 UTC (permalink / raw)
  To: linux-arm-kernel

Optimize memcpy_{from,to}io() and memset_io() by transferring in 64 bit
as much as possible with minimized barrier usage.  This simplest optimization
brings faster throughput compare to current byte-by-byte read and write with
barrier in the loop.  Code's skeleton is taken from the powerpc.

Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
Acked-by: Trilok Soni <tsoni@codeaurora.org>
---
 arch/arm64/kernel/io.c | 72 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 62 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/io.c b/arch/arm64/kernel/io.c
index 7d37ead..c0e3ab1 100644
--- a/arch/arm64/kernel/io.c
+++ b/arch/arm64/kernel/io.c
@@ -20,18 +20,34 @@
 #include <linux/types.h>
 #include <linux/io.h>
 
+#define IO_CHECK_ALIGN(v, a) ((((unsigned long)(v)) & ((a) - 1)) == 0)
+
 /*
  * Copy data from IO memory space to "real" memory space.
  */
 void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
 {
-	unsigned char *t = to;
-	while (count) {
+	while (count && (!IO_CHECK_ALIGN(from, 8) || !IO_CHECK_ALIGN(to, 8))) {
+		*(u8 *)to = readb_relaxed(from);
+		from++;
+		to++;
 		count--;
-		*t = readb(from);
-		t++;
+	}
+
+	while (count >= 8) {
+		*(u64 *)to = readq_relaxed(from);
+		from += 8;
+		to += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		*(u8 *)to = readb_relaxed(from);
 		from++;
+		to++;
+		count--;
 	}
+	__iormb();
 }
 EXPORT_SYMBOL(__memcpy_fromio);
 
@@ -40,12 +56,28 @@ EXPORT_SYMBOL(__memcpy_fromio);
  */
 void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
 {
-	const unsigned char *f = from;
+	void *p = (void __force *)from;
+
+	__iowmb();
+	while (count && (!IO_CHECK_ALIGN(p, 8) || !IO_CHECK_ALIGN(from, 8))) {
+		writeb_relaxed(*(volatile u8 *)from, p);
+		from++;
+		p++;
+		count--;
+	}
+
+	while (count >= 8) {
+		writeq_relaxed(*(volatile u64 *)from, p);
+		from += 8;
+		p += 8;
+		count -= 8;
+	}
+
 	while (count) {
+		writeb_relaxed(*(volatile u8 *)from, p);
+		from++;
+		p++;
 		count--;
-		writeb(*f, to);
-		f++;
-		to++;
 	}
 }
 EXPORT_SYMBOL(__memcpy_toio);
@@ -55,10 +87,30 @@ EXPORT_SYMBOL(__memcpy_toio);
  */
 void __memset_io(volatile void __iomem *dst, int c, size_t count)
 {
+	void *p = (void __force *)dst;
+	u64 qc = c;
+
+	qc |= qc << 8;
+	qc |= qc << 16;
+	qc |= qc << 32;
+
+	__iowmb();
+	while (count && !IO_CHECK_ALIGN(p, 8)) {
+		writeb_relaxed(c, p);
+		p++;
+		count--;
+	}
+
+	while (count >= 8) {
+		writeq_relaxed(c, p);
+		p += 8;
+		count -= 8;
+	}
+
 	while (count) {
+		writeb_relaxed(c, p);
+		p++;
 		count--;
-		writeb(c, dst);
-		dst++;
 	}
 }
 EXPORT_SYMBOL(__memset_io);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH] arm64: optimize memcpy_{from,to}io() and memset_io()
@ 2014-10-21  0:59 Joonwoo Park
  0 siblings, 0 replies; 12+ messages in thread
From: Joonwoo Park @ 2014-10-21  0:59 UTC (permalink / raw)
  To: linux-arm-kernel

Optimize memcpy_{from,to}io() and memset_io() by transferring in 64 bit
as much as possible with minimized barrier usage.  This simplest
optimization brings faster throughput compare to current byte-by-byte read
and write with barrier in the loop.  Code's skeleton is taken from the
powerpc.

Link: http://lkml.kernel.org/p/20141020133304.GH23751 at e104818-lin.cambridge.arm.com
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Trilok Soni <tsoni@codeaurora.org>
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
---
 arch/arm64/kernel/io.c | 66 ++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 56 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kernel/io.c b/arch/arm64/kernel/io.c
index 7d37ead..354be2a 100644
--- a/arch/arm64/kernel/io.c
+++ b/arch/arm64/kernel/io.c
@@ -25,12 +25,26 @@
  */
 void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
 {
-	unsigned char *t = to;
-	while (count) {
+	while (count && (!IS_ALIGNED((unsigned long)from, 8) ||
+			 !IS_ALIGNED((unsigned long)to, 8))) {
+		*(u8 *)to = __raw_readb(from);
+		from++;
+		to++;
 		count--;
-		*t = readb(from);
-		t++;
+	}
+
+	while (count >= 8) {
+		*(u64 *)to = __raw_readq(from);
+		from += 8;
+		to += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		*(u8 *)to = __raw_readb(from);
 		from++;
+		to++;
+		count--;
 	}
 }
 EXPORT_SYMBOL(__memcpy_fromio);
@@ -40,12 +54,26 @@ EXPORT_SYMBOL(__memcpy_fromio);
  */
 void __memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
 {
-	const unsigned char *f = from;
-	while (count) {
+	while (count && (!IS_ALIGNED((unsigned long)to, 8) ||
+			 !IS_ALIGNED((unsigned long)from, 8))) {
+		__raw_writeb(*(volatile u8 *)from, to);
+		from++;
+		to++;
 		count--;
-		writeb(*f, to);
-		f++;
+	}
+
+	while (count >= 8) {
+		__raw_writeq(*(volatile u64 *)from, to);
+		from += 8;
+		to += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		__raw_writeb(*(volatile u8 *)from, to);
+		from++;
 		to++;
+		count--;
 	}
 }
 EXPORT_SYMBOL(__memcpy_toio);
@@ -55,10 +83,28 @@ EXPORT_SYMBOL(__memcpy_toio);
  */
 void __memset_io(volatile void __iomem *dst, int c, size_t count)
 {
-	while (count) {
+	u64 qc = (u8)c;
+
+	qc |= qc << 8;
+	qc |= qc << 16;
+	qc |= qc << 32;
+
+	while (count && !IS_ALIGNED((unsigned long)dst, 8)) {
+		__raw_writeb(c, dst);
+		dst++;
 		count--;
-		writeb(c, dst);
+	}
+
+	while (count >= 8) {
+		__raw_writeq(qc, dst);
+		dst += 8;
+		count -= 8;
+	}
+
+	while (count) {
+		__raw_writeb(c, dst);
 		dst++;
+		count--;
 	}
 }
 EXPORT_SYMBOL(__memset_io);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

^ permalink raw reply related	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2014-10-21  0:59 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-07-30  6:28 [PATCH] arm64: optimize memcpy_{from,to}io() and memset_io() Joonwoo Park
2014-08-01  6:30 ` Joonwoo Park
2014-08-01  8:32   ` Will Deacon
2014-08-02  1:38     ` Joonwoo Park
2014-08-04  9:57       ` Will Deacon
2014-10-03 16:31   ` Catalin Marinas
2014-10-09  2:39     ` Joonwoo Park
2014-10-09 10:16       ` Catalin Marinas
2014-10-14  4:04         ` Joonwoo Park
2014-10-14  4:12           ` Joonwoo Park
2014-10-20 13:33             ` Catalin Marinas
  -- strict thread matches above, loose matches on Subject: below --
2014-10-21  0:59 Joonwoo Park

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