Thread (1 message) 1 message, 1 author, 2015-03-18

Re: [PATCH 1/3 v3] librte_hash: Fix unsupported instruction `crc32' in i686 platform

From: Qiu, Michael <hidden>
Date: 2015-03-18 14:59:27

Hi, Yong

If the platform is i686, dpdk will use software crc function.

Thanks,
Michael

-----Original Message-----
From: Liu, Yong 
Sent: Wednesday, March 18, 2015 9:21 PM
To: Qiu, Michael; thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org; dev-VfR2kkLFssw@public.gmane.org
Cc: yerden.zhumabekov-8EHiFRVJVgQ@public.gmane.org
Subject: RE: [dpdk-dev] [PATCH 1/3 v3] librte_hash: Fix unsupported instruction `crc32' in i686 platform

Michael & Thomas,

Should we use software crc function replace of hardware crc function in 'crc32c_sse42_u64' when arch is i686?
Thus application still can use CRC32_SSE42_x64 algorithm for crc calculation when build with i686 configuration.
This may helpful for simplify application code.
quoted hunk
-----Original Message-----
From: dev [mailto:dev-bounces-VfR2kkLFssw@public.gmane.org] On Behalf Of Michael Qiu
Sent: Monday, March 09, 2015 1:58 PM
To: dev-VfR2kkLFssw@public.gmane.org
Cc: yerden.zhumabekov-8EHiFRVJVgQ@public.gmane.org
Subject: [dpdk-dev] [PATCH 1/3 v3] librte_hash: Fix unsupported 
instruction `crc32' in i686 platform

CC rte_hash.o
Error: unsupported instruction `crc32'

The root cause is that i686 platform does not support 'crc32q'
Need make it only available in x86_64 platform

Signed-off-by: Michael Qiu <redacted>
Acked-by: Yerden Zhumabekov <redacted>
---
v3 --> v2:
	Add sub function for #else which returns 0
v2 --> v1:
         Make crc32 instruction only works in X86 platform

 lib/librte_hash/rte_hash_crc.h | 46 
+++++++++++++++++++++++++++++++++----
-----
 1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/lib/librte_hash/rte_hash_crc.h 
b/lib/librte_hash/rte_hash_crc.h index d28bb2a..f1dbded 100644
--- a/lib/librte_hash/rte_hash_crc.h
+++ b/lib/librte_hash/rte_hash_crc.h
@@ -47,6 +47,7 @@ extern "C" {
 #include <stdint.h>
 #include <rte_cpuflags.h>
 #include <rte_branch_prediction.h>
+#include <rte_common.h>

 /* Lookup tables for software implementation of CRC32C */  static 
const uint32_t crc32c_tables[8][256] = {{ @@ -364,6 +365,7 @@ 
crc32c_2words(uint64_t data, uint32_t init_val)
 	return crc;
 }

+#if defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_64)
 static inline uint32_t
 crc32c_sse42_u32(uint32_t data, uint32_t init_val)  { @@ -375,16 
+377,6 @@ crc32c_sse42_u32(uint32_t data, uint32_t init_val)  }

 static inline uint32_t
-crc32c_sse42_u64(uint64_t data, uint64_t init_val) -{
-	__asm__ volatile(
-			"crc32q %[data], %[init_val];"
-			: [init_val] "+r" (init_val)
-			: [data] "rm" (data));
-	return init_val;
-}
-
-static inline uint32_t
 crc32c_sse42_u64_mimic(uint64_t data, uint64_t init_val)  {
 	union {
@@ -397,6 +389,40 @@ crc32c_sse42_u64_mimic(uint64_t data, uint64_t
init_val)
 	init_val = crc32c_sse42_u32(d.u32[1], init_val);
 	return init_val;
 }
+#else
+static inline uint32_t
+crc32c_sse42_u32(__rte_unused uint32_t data,
+		 __rte_unused uint32_t init_val)
+{
+	return 0;
+}
+
+static inline uint32_t
+crc32c_sse42_u64_mimic(__rte_unused uint32_t data,
+		       __rte_unused uint32_t init_val) {
+	return 0;
+}
+#endif
+
+#ifdef RTE_ARCH_X86_64
+static inline uint32_t
+crc32c_sse42_u64(uint64_t data, uint64_t init_val) {
+	__asm__ volatile(
+			"crc32q %[data], %[init_val];"
+			: [init_val] "+r" (init_val)
+			: [data] "rm" (data));
+	return init_val;
+}
+#else
+static inline uint32_t
+crc32c_sse42_u64(__rte_unused uint64_t data,
+		 __rte_unused uint64_t init_val)
+{

	return crc32c_2words(data, init_val);

+	return 0;
+}
+#endif

 #define CRC32_SW            (1U << 0)
 #define CRC32_SSE42         (1U << 1)
--
1.9.3
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