[dpdk-dev] [PATCH v2 1/2] eal: introduce rte_prefetch_non_temporal

[Jerin Jacob]

non-temporal/transient/stream version of rte_prefetch0()

The non-temporal prefetch is intended as a prefetch hint that processor
will use the prefetched data only once or short period,
unlike the rte_prefetch0() function which imply that
prefetched data to use repeatedly.

Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
Acked-by: Jan Viktorin <viktorin at rehivetech.com>
---
 lib/librte_eal/common/include/arch/arm/rte_prefetch_32.h |  6 ++++++
 lib/librte_eal/common/include/arch/arm/rte_prefetch_64.h |  5 +++++
 lib/librte_eal/common/include/arch/ppc_64/rte_prefetch.h |  6 ++++++
 lib/librte_eal/common/include/arch/tile/rte_prefetch.h   |  6 ++++++
 lib/librte_eal/common/include/arch/x86/rte_prefetch.h    |  5 +++++
 lib/librte_eal/common/include/generic/rte_prefetch.h     | 12 ++++++++++++
 6 files changed, 40 insertions(+)

diff --git a/lib/librte_eal/common/include/arch/arm/rte_prefetch_32.h b/lib/librte_eal/common/include/arch/arm/rte_prefetch_32.h
index b716384..5aeed22 100644
--- a/lib/librte_eal/common/include/arch/arm/rte_prefetch_32.h
+++ b/lib/librte_eal/common/include/arch/arm/rte_prefetch_32.h
@@ -54,6 +54,12 @@ static inline void rte_prefetch2(const volatile void *p)
 	asm volatile ("pld [%0]" : : "r" (p));
 }
 
+static inline void rte_prefetch_non_temporal(const volatile void *p)
+{
+	/* non-temporal version not available, fallback to rte_prefetch0 */
+	rte_prefetch0(p);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/common/include/arch/arm/rte_prefetch_64.h b/lib/librte_eal/common/include/arch/arm/rte_prefetch_64.h
index f9cc62e..3ed46a4 100644
--- a/lib/librte_eal/common/include/arch/arm/rte_prefetch_64.h
+++ b/lib/librte_eal/common/include/arch/arm/rte_prefetch_64.h
@@ -54,6 +54,11 @@ static inline void rte_prefetch2(const volatile void *p)
 	asm volatile ("PRFM PLDL3KEEP, [%0]" : : "r" (p));
 }
 
+static inline void rte_prefetch_non_temporal(const volatile void *p)
+{
+	asm volatile ("PRFM PLDL1STRM, [%0]" : : "r" (p));
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/common/include/arch/ppc_64/rte_prefetch.h b/lib/librte_eal/common/include/arch/ppc_64/rte_prefetch.h
index fea3be1..bcc7185 100644
--- a/lib/librte_eal/common/include/arch/ppc_64/rte_prefetch.h
+++ b/lib/librte_eal/common/include/arch/ppc_64/rte_prefetch.h
@@ -54,6 +54,12 @@ static inline void rte_prefetch2(const volatile void *p)
 	asm volatile ("dcbt 0,%[p],1" : : [p] "r" (p));
 }
 
+static inline void rte_prefetch_non_temporal(const volatile void *p)
+{
+	/* non-temporal version not available, fallback to rte_prefetch0 */
+	rte_prefetch0(p);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/common/include/arch/tile/rte_prefetch.h b/lib/librte_eal/common/include/arch/tile/rte_prefetch.h
index c94075c..7a1bb93 100644
--- a/lib/librte_eal/common/include/arch/tile/rte_prefetch.h
+++ b/lib/librte_eal/common/include/arch/tile/rte_prefetch.h
@@ -54,6 +54,12 @@ static inline void rte_prefetch2(const volatile void *p)
 	__builtin_prefetch((const void *)(uintptr_t)p, 0, 1);
 }
 
+static inline void rte_prefetch_non_temporal(const volatile void *p)
+{
+	/* non-temporal version not available, fallback to rte_prefetch0 */
+	rte_prefetch0(p);
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/common/include/arch/x86/rte_prefetch.h b/lib/librte_eal/common/include/arch/x86/rte_prefetch.h
index 8e6e02c..5dac47e 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_prefetch.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_prefetch.h
@@ -55,6 +55,11 @@ static inline void rte_prefetch2(const volatile void *p)
 	asm volatile ("prefetcht2 %[p]" : : [p] "m" (*(const volatile char *)p));
 }
 
+static inline void rte_prefetch_non_temporal(const volatile void *p)
+{
+	asm volatile ("prefetchnta %[p]" : : [p] "m" (*(const volatile char *)p));
+}
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/common/include/generic/rte_prefetch.h b/lib/librte_eal/common/include/generic/rte_prefetch.h
index 725715f..07e409e 100644
--- a/lib/librte_eal/common/include/generic/rte_prefetch.h
+++ b/lib/librte_eal/common/include/generic/rte_prefetch.h
@@ -68,4 +68,16 @@ static inline void rte_prefetch1(const volatile void *p);
  */
 static inline void rte_prefetch2(const volatile void *p);
 
+/**
+ * Prefetch a cache line into all cache levels (non-temporal/transient version)
+ *
+ * The non-temporal prefetch is intended as a prefetch hint that processor will
+ * use the prefetched data only once or short period, unlike the
+ * rte_prefetch0() function which imply that prefetched data to use repeatedly.
+ *
+ * @param p
+ *   Address to prefetch
+ */
+static inline void rte_prefetch_non_temporal(const volatile void *p);
+
 #endif /* _RTE_PREFETCH_H_ */
-- 
2.1.0