Implementation of vdev_raidz generate and reconstruct routines

- specialized gen/rec routines for all RAIDZ levels,
- new scalar raidz implementation (unrolled),
- two x86_64 SIMD implementations (SSE_4.1 and AVX2 instructions sets),
- fastest routines selected on module load (benchmark).

New zfs module parameters:
- zfs_raidz_math_impl (int): selects a new implementation to use:
    "-1" - the fastest (DEFAULT),
     "0" - new scalar routines,
     "1" - new SSE routines,
     "2" - new AVX2 routines.

- zfs_raidz_new_math (uint): enables or disables new implementations:
    "1" - use new raidz implementation (DEFAULT),
    "0" - use old raidz implementation.

vdev_raidz_math: fix AVX2 code compilation against kernels older and newer than ~3.16
kernel comp: fix CPU feature check for new kernels
vdev_raidz_math_scalar: fix function prototype inconsistencies

cmd/zdb/zdb.c

@@ -3612,6 +3612,9 @@ find_zpool(char **target, nvlist_t **configp, int dirc, char **dirv)
 	return (name);
 }
 
+/* init raidz math */
+extern void raidz_math_bench(void);
+
 int
 main(int argc, char **argv)
 {
@@ -3635,6 +3638,8 @@ main(int argc, char **argv)
 	(void) setrlimit(RLIMIT_NOFILE, &rl);
 	(void) enable_extended_FILE_stdio(-1, -1);
 
+	raidz_math_bench();
+
 	dprintf_setup(&argc, argv);
 
 	/*

cmd/ztest/ztest.c

@@ -6355,6 +6355,9 @@ ztest_run_init(void)
 	}
 }
 
+/* init raidz math */
+extern void raidz_math_bench(void);
+
 int
 main(int argc, char **argv)
 {
@@ -6374,6 +6377,8 @@ main(int argc, char **argv)
 	char *fd_data_str = getenv("ZTEST_FD_DATA");
 	struct sigaction action;
 
+	raidz_math_bench();
+
 	(void) setvbuf(stdout, NULL, _IOLBF, 0);
 
 	dprintf_setup(&argc, argv);

lib/libzpool/Makefile.am

@@ -90,6 +90,8 @@ KERNEL_C = \
 	vdev_missing.c \
 	vdev_queue.c \
 	vdev_raidz.c \
+	vdev_raidz_math.c \
+	vdev_raidz_math_scalar.c \
 	vdev_root.c \
 	zap.c \
 	zap_leaf.c \

module/zfs/Makefile.in

@@ -69,6 +69,8 @@ $(MODULE)-objs += vdev_mirror.o
 $(MODULE)-objs += vdev_missing.o
 $(MODULE)-objs += vdev_queue.o
 $(MODULE)-objs += vdev_raidz.o
+$(MODULE)-objs += vdev_raidz_math.o
+$(MODULE)-objs += vdev_raidz_math_scalar.o
 $(MODULE)-objs += vdev_root.o
 $(MODULE)-objs += zap.o
 $(MODULE)-objs += zap_leaf.o
@@ -107,3 +109,6 @@ $(MODULE)-objs += zrlock.o
 $(MODULE)-objs += zvol.o
 $(MODULE)-objs += dsl_destroy.o
 $(MODULE)-objs += dsl_userhold.o
+
+$(MODULE)-$(CONFIG_X86) += vdev_raidz_math_sse.o
+$(MODULE)-$(CONFIG_X86) += vdev_raidz_math_avx2.o

module/zfs/vdev_raidz.c

@@ -22,6 +22,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (C) 2016 Gvozden Nešković. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -32,6 +33,8 @@
 #include <sys/fs/zfs.h>
 #include <sys/fm/fs/zfs.h>
 
+#include "vdev_raidz.h"
+
 /*
  * Virtual device vector for RAID-Z.
  *
@@ -99,33 +102,6 @@
  * or in concert to recover missing data columns.
  */
 
-typedef struct raidz_col {
-	uint64_t rc_devidx;		/* child device index for I/O */
-	uint64_t rc_offset;		/* device offset */
-	uint64_t rc_size;		/* I/O size */
-	void *rc_data;			/* I/O data */
-	void *rc_gdata;			/* used to store the "good" version */
-	int rc_error;			/* I/O error for this device */
-	uint8_t rc_tried;		/* Did we attempt this I/O column? */
-	uint8_t rc_skipped;		/* Did we skip this I/O column? */
-} raidz_col_t;
-
-typedef struct raidz_map {
-	uint64_t rm_cols;		/* Regular column count */
-	uint64_t rm_scols;		/* Count including skipped columns */
-	uint64_t rm_bigcols;		/* Number of oversized columns */
-	uint64_t rm_asize;		/* Actual total I/O size */
-	uint64_t rm_missingdata;	/* Count of missing data devices */
-	uint64_t rm_missingparity;	/* Count of missing parity devices */
-	uint64_t rm_firstdatacol;	/* First data column/parity count */
-	uint64_t rm_nskip;		/* Skipped sectors for padding */
-	uint64_t rm_skipstart;		/* Column index of padding start */
-	void *rm_datacopy;		/* rm_asize-buffer of copied data */
-	uintptr_t rm_reports;		/* # of referencing checksum reports */
-	uint8_t	rm_freed;		/* map no longer has referencing ZIO */
-	uint8_t	rm_ecksuminjected;	/* checksum error was injected */
-	raidz_col_t rm_col[1];		/* Flexible array of I/O columns */
-} raidz_map_t;
 
 #define	VDEV_RAIDZ_P		0
 #define	VDEV_RAIDZ_Q		1
@@ -159,97 +135,14 @@ typedef struct raidz_map {
  */
 int vdev_raidz_default_to_general;
 
-/* Powers of 2 in the Galois field defined above. */
-static const uint8_t vdev_raidz_pow2[256] = {
-	0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80,
-	0x1d, 0x3a, 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26,
-	0x4c, 0x98, 0x2d, 0x5a, 0xb4, 0x75, 0xea, 0xc9,
-	0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30, 0x60, 0xc0,
-	0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35,
-	0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23,
-	0x46, 0x8c, 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0,
-	0x5d, 0xba, 0x69, 0xd2, 0xb9, 0x6f, 0xde, 0xa1,
-	0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f, 0x5e, 0xbc,
-	0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0,
-	0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f,
-	0xfe, 0xe1, 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2,
-	0xd9, 0xaf, 0x43, 0x86, 0x11, 0x22, 0x44, 0x88,
-	0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd, 0x67, 0xce,
-	0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93,
-	0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc,
-	0x85, 0x17, 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9,
-	0x4f, 0x9e, 0x21, 0x42, 0x84, 0x15, 0x2a, 0x54,
-	0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4, 0x55, 0xaa,
-	0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73,
-	0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e,
-	0xfc, 0xe5, 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff,
-	0xe3, 0xdb, 0xab, 0x4b, 0x96, 0x31, 0x62, 0xc4,
-	0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57, 0xae, 0x41,
-	0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e,
-	0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6,
-	0x51, 0xa2, 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef,
-	0xc3, 0x9b, 0x2b, 0x56, 0xac, 0x45, 0x8a, 0x09,
-	0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a, 0xf4, 0xf5,
-	0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16,
-	0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83,
-	0x1b, 0x36, 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x01
-};
-/* Logs of 2 in the Galois field defined above. */
-static const uint8_t vdev_raidz_log2[256] = {
-	0x00, 0x00, 0x01, 0x19, 0x02, 0x32, 0x1a, 0xc6,
-	0x03, 0xdf, 0x33, 0xee, 0x1b, 0x68, 0xc7, 0x4b,
-	0x04, 0x64, 0xe0, 0x0e, 0x34, 0x8d, 0xef, 0x81,
-	0x1c, 0xc1, 0x69, 0xf8, 0xc8, 0x08, 0x4c, 0x71,
-	0x05, 0x8a, 0x65, 0x2f, 0xe1, 0x24, 0x0f, 0x21,
-	0x35, 0x93, 0x8e, 0xda, 0xf0, 0x12, 0x82, 0x45,
-	0x1d, 0xb5, 0xc2, 0x7d, 0x6a, 0x27, 0xf9, 0xb9,
-	0xc9, 0x9a, 0x09, 0x78, 0x4d, 0xe4, 0x72, 0xa6,
-	0x06, 0xbf, 0x8b, 0x62, 0x66, 0xdd, 0x30, 0xfd,
-	0xe2, 0x98, 0x25, 0xb3, 0x10, 0x91, 0x22, 0x88,
-	0x36, 0xd0, 0x94, 0xce, 0x8f, 0x96, 0xdb, 0xbd,
-	0xf1, 0xd2, 0x13, 0x5c, 0x83, 0x38, 0x46, 0x40,
-	0x1e, 0x42, 0xb6, 0xa3, 0xc3, 0x48, 0x7e, 0x6e,
-	0x6b, 0x3a, 0x28, 0x54, 0xfa, 0x85, 0xba, 0x3d,
-	0xca, 0x5e, 0x9b, 0x9f, 0x0a, 0x15, 0x79, 0x2b,
-	0x4e, 0xd4, 0xe5, 0xac, 0x73, 0xf3, 0xa7, 0x57,
-	0x07, 0x70, 0xc0, 0xf7, 0x8c, 0x80, 0x63, 0x0d,
-	0x67, 0x4a, 0xde, 0xed, 0x31, 0xc5, 0xfe, 0x18,
-	0xe3, 0xa5, 0x99, 0x77, 0x26, 0xb8, 0xb4, 0x7c,
-	0x11, 0x44, 0x92, 0xd9, 0x23, 0x20, 0x89, 0x2e,
-	0x37, 0x3f, 0xd1, 0x5b, 0x95, 0xbc, 0xcf, 0xcd,
-	0x90, 0x87, 0x97, 0xb2, 0xdc, 0xfc, 0xbe, 0x61,
-	0xf2, 0x56, 0xd3, 0xab, 0x14, 0x2a, 0x5d, 0x9e,
-	0x84, 0x3c, 0x39, 0x53, 0x47, 0x6d, 0x41, 0xa2,
-	0x1f, 0x2d, 0x43, 0xd8, 0xb7, 0x7b, 0xa4, 0x76,
-	0xc4, 0x17, 0x49, 0xec, 0x7f, 0x0c, 0x6f, 0xf6,
-	0x6c, 0xa1, 0x3b, 0x52, 0x29, 0x9d, 0x55, 0xaa,
-	0xfb, 0x60, 0x86, 0xb1, 0xbb, 0xcc, 0x3e, 0x5a,
-	0xcb, 0x59, 0x5f, 0xb0, 0x9c, 0xa9, 0xa0, 0x51,
-	0x0b, 0xf5, 0x16, 0xeb, 0x7a, 0x75, 0x2c, 0xd7,
-	0x4f, 0xae, 0xd5, 0xe9, 0xe6, 0xe7, 0xad, 0xe8,
-	0x74, 0xd6, 0xf4, 0xea, 0xa8, 0x50, 0x58, 0xaf,
-};
-
-static void vdev_raidz_generate_parity(raidz_map_t *rm);
-
 /*
- * Multiply a given number by 2 raised to the given power.
+ * Select a new raidz implementation by default.
  */
-static uint8_t
-vdev_raidz_exp2(uint_t a, int exp)
-{
-	if (a == 0)
-		return (0);
+unsigned long zfs_raidz_new_math = 1;
 
-	ASSERT(exp >= 0);
-	ASSERT(vdev_raidz_log2[a] > 0 || a == 1);
 
-	exp += vdev_raidz_log2[a];
-	if (exp > 255)
-		exp -= 255;
+static void vdev_raidz_generate_parity(raidz_map_t *rm);
 
-	return (vdev_raidz_pow2[exp]);
-}
 
 static void
 vdev_raidz_map_free(raidz_map_t *rm)
@@ -272,6 +165,9 @@ vdev_raidz_map_free(raidz_map_t *rm)
 	if (rm->rm_datacopy != NULL)
 		zio_buf_free(rm->rm_datacopy, size);
 
+	/* Free the raidz math plan */
+	raidz_math_plan_free(rm->rm_mathplan);
+
 	kmem_free(rm, offsetof(raidz_map_t, rm_col[rm->rm_scols]));
 }
 
@@ -579,6 +475,10 @@ vdev_raidz_map_alloc(zio_t *zio, uint64_t unit_shift, uint64_t dcols,
 
 	zio->io_vsd = rm;
 	zio->io_vsd_ops = &vdev_raidz_vsd_ops;
+
+	/* Math plan */
+	rm->rm_mathplan = raidz_math_plan_alloc(rm);
+
 	return (rm);
 }
 
@@ -729,6 +629,11 @@ vdev_raidz_generate_parity_pqr(raidz_map_t *rm)
 static void
 vdev_raidz_generate_parity(raidz_map_t *rm)
 {
+	if(zfs_raidz_new_math != 0) {
+		raidz_math_generate(rm->rm_mathplan);
+		return;
+	}
+
 	switch (rm->rm_firstdatacol) {
 	case 1:
 		vdev_raidz_generate_parity_p(rm);
@@ -1435,6 +1340,14 @@ vdev_raidz_reconstruct(raidz_map_t *rm, int *t, int nt)
 
 	dt = &tgts[nbadparity];
 
+	/*
+	 * Reconstruct using the new math implementation.
+	 */
+	if(zfs_raidz_new_math != 0) {
+		return (raidz_math_reconstruct(rm->rm_mathplan,
+			parity_valid, dt, nbaddata));
+	}
+
 	/*
 	 * See if we can use any of our optimized reconstruction routines.
 	 */
@@ -2220,3 +2133,8 @@ vdev_ops_t vdev_raidz_ops = {
 	VDEV_TYPE_RAIDZ,	/* name of this vdev type */
 	B_FALSE			/* not a leaf vdev */
 };
+
+#if defined(_KERNEL) && defined(HAVE_SPL)
+module_param(zfs_raidz_new_math, ulong, 0644);
+MODULE_PARM_DESC(zfs_raidz_new_math, "Select raidz implementation: old(0), new(!=0)");
+#endif