SIMD implementation of vdev_raidz generate and reconstruct routines

This is a new implementation of RAIDZ1/2/3 routines using x86_64
scalar, SSE, and AVX2 instruction sets. Included are 3 parity
generation routines (P, PQ, and PQR) and 7 reconstruction routines,
for all RAIDZ level. On module load, a quick benchmark of supported
routines will select the fastest for each operation and they will
be used at runtime. Original implementation is still present and
can be selected via module parameter.

Patch contains:
- specialized gen/rec routines for all RAIDZ levels,
- new scalar raidz implementation (unrolled),
- two x86_64 SIMD implementations (SSE and AVX2 instructions sets),
- fastest routines selected on module load (benchmark).
- cmd/raidz_test - verify and benchmark all implementations
- added raidz_test to the ZFS Test Suite

New zfs module parameters:
- zfs_vdev_raidz_impl (str): selects the implementation to use. On
  module load, the parameter will only accept first 3 options, and
  the other implementations can be set once module is finished
  loading. Possible values for this option are:
    "fastest" - use the fastest math available
    "original" - use the original raidz code
    "scalar" - new scalar impl
    "sse" - new SSE impl if available
    "avx2" - new AVX2 impl if available

See contents of `/sys/module/zfs/parameters/zfs_vdev_raidz_impl` to
get the list of supported values. If an implementation is not supported
on the system, it will not be shown. Currently selected option is
enclosed in `[]`.

Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#4328

cmd/Makefile.am

@@ -1,3 +1,3 @@
 SUBDIRS  = zfs zpool zdb zhack zinject zstreamdump ztest zpios
 SUBDIRS += mount_zfs fsck_zfs zvol_id vdev_id arcstat dbufstat zed
-SUBDIRS += arc_summary
+SUBDIRS += arc_summary raidz_test

cmd/raidz_test/.gitignore

@@ -0,0 +1 @@
+/raidz_test

cmd/raidz_test/Makefile.am

@@ -0,0 +1,21 @@
+include $(top_srcdir)/config/Rules.am
+
+AM_CFLAGS += $(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+AM_CPPFLAGS += -DDEBUG
+
+DEFAULT_INCLUDES += \
+	-I$(top_srcdir)/include \
+	-I$(top_srcdir)/lib/libspl/include
+
+bin_PROGRAMS = raidz_test
+
+raidz_test_SOURCES = \
+	raidz_test.h \
+	raidz_test.c \
+	raidz_bench.c
+
+raidz_test_LDADD = \
+	$(top_builddir)/lib/libuutil/libuutil.la \
+	$(top_builddir)/lib/libzpool/libzpool.la
+
+raidz_test_LDADD += -lm -ldl

cmd/raidz_test/raidz_bench.c

@@ -0,0 +1,241 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (C) 2016 Gvozden Nešković. All rights reserved.
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <sys/zio.h>
+#include <sys/vdev_raidz.h>
+#include <sys/vdev_raidz_impl.h>
+#include <stdio.h>
+
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include "raidz_test.h"
+
+#define	GEN_BENCH_MEMORY	(((uint64_t)1ULL)<<32)
+#define	REC_BENCH_MEMORY	(((uint64_t)1ULL)<<29)
+#define	BENCH_ASHIFT		12
+#define	MIN_CS_SHIFT		BENCH_ASHIFT
+#define	MAX_CS_SHIFT		SPA_MAXBLOCKSHIFT
+
+
+static zio_t zio_bench;
+static raidz_map_t *rm_bench;
+static size_t max_data_size = SPA_MAXBLOCKSIZE;
+
+static void
+bench_init_raidz_map(void)
+{
+	zio_bench.io_offset = 0;
+	zio_bench.io_size = max_data_size;
+
+	/*
+	 * To permit larger column sizes these have to be done
+	 * allocated using aligned alloc instead of zio_data_buf_alloc
+	 */
+	zio_bench.io_data = raidz_alloc(max_data_size);
+
+	init_zio_data(&zio_bench);
+}
+
+static void
+bench_fini_raidz_maps(void)
+{
+	/* tear down golden zio */
+	raidz_free(zio_bench.io_data, max_data_size);
+	bzero(&zio_bench, sizeof (zio_t));
+}
+
+static double
+get_time_diff(struct rusage *start, struct rusage *stop)
+{
+	return (((double)stop->ru_utime.tv_sec * (double)MICROSEC +
+		(double)stop->ru_utime.tv_usec) -
+		((double)start->ru_utime.tv_sec * (double)MICROSEC +
+		(double)start->ru_utime.tv_usec)) / (double)MICROSEC;
+}
+
+static inline void
+run_gen_bench_impl(const char *impl)
+{
+	int fn, ncols;
+	uint64_t ds, iter_cnt, iter, disksize;
+	struct rusage start, stop;
+	double elapsed, d_bw;
+
+	/* Benchmark generate functions */
+	for (fn = 0; fn < RAIDZ_GEN_NUM; fn++) {
+
+		for (ds = MIN_CS_SHIFT; ds <= MAX_CS_SHIFT; ds++) {
+
+			/* create suitable raidz_map */
+			ncols = rto_opts.rto_dcols + fn + 1;
+			zio_bench.io_size = 1ULL << ds;
+			rm_bench = vdev_raidz_map_alloc(&zio_bench,
+			    BENCH_ASHIFT, ncols, fn+1);
+
+			/* estimate iteration count */
+			iter_cnt = GEN_BENCH_MEMORY;
+			iter_cnt /= zio_bench.io_size;
+
+			getrusage(RUSAGE_THREAD, &start);
+			for (iter = 0; iter < iter_cnt; iter++)
+				vdev_raidz_generate_parity(rm_bench);
+			getrusage(RUSAGE_THREAD, &stop);
+
+			elapsed = get_time_diff(&start, &stop);
+			disksize = (1ULL << ds) / rto_opts.rto_dcols;
+			d_bw = (double)iter_cnt * (double)disksize;
+			d_bw /= (1024.0 * 1024.0 * elapsed);
+
+			LOG(D_ALL, "%10s, %8s, %zu, %10llu, %lf, %lf, %u\n",
+			    impl,
+			    raidz_gen_name[fn],
+			    rto_opts.rto_dcols,
+			    (1ULL<<ds),
+			    d_bw,
+			    d_bw * (double)(ncols),
+			    (unsigned) iter_cnt);
+
+			vdev_raidz_map_free(rm_bench);
+		}
+	}
+}
+
+void
+run_gen_bench(void)
+{
+	char **impl_name;
+
+	LOG(D_INFO, DBLSEP "\nBenchmarking parity generation...\n\n");
+	LOG(D_ALL, "impl, math, dcols, iosize, disk_bw, total_bw, iter\n");
+
+	for (impl_name = (char **)raidz_impl_names; *impl_name != NULL;
+	    impl_name++) {
+
+		if (vdev_raidz_impl_set(*impl_name) != 0)
+			continue;
+
+		run_gen_bench_impl(*impl_name);
+	}
+}
+
+static void
+run_rec_bench_impl(const char *impl)
+{
+	struct rusage start, stop;
+	int fn, ncols, nbad;
+	uint64_t ds, iter_cnt, iter, disksize;
+	double elapsed, d_bw;
+	static const int tgt[7][3] = {
+		{1, 2, 3},	/* rec_p:   bad QR & D[0]	*/
+		{0, 2, 3},	/* rec_q:   bad PR & D[0]	*/
+		{0, 1, 3},	/* rec_r:   bad PQ & D[0]	*/
+		{2, 3, 4},	/* rec_pq:  bad R  & D[0][1]	*/
+		{1, 3, 4},	/* rec_pr:  bad Q  & D[0][1]	*/
+		{0, 3, 4},	/* rec_qr:  bad P  & D[0][1]	*/
+		{3, 4, 5}	/* rec_pqr: bad    & D[0][1][2] */
+	};
+
+	for (fn = 0; fn < RAIDZ_REC_NUM; fn++) {
+		for (ds = MIN_CS_SHIFT; ds <= MAX_CS_SHIFT; ds++) {
+
+			/* create suitable raidz_map */
+			ncols = rto_opts.rto_dcols + PARITY_PQR;
+			zio_bench.io_size = 1ULL << ds;
+
+			/*
+			 * raidz block is too short to test
+			 * the requested method
+			 */
+			if (zio_bench.io_size / rto_opts.rto_dcols <
+			    (1ULL << BENCH_ASHIFT))
+				continue;
+
+			rm_bench = vdev_raidz_map_alloc(&zio_bench,
+				BENCH_ASHIFT, ncols, PARITY_PQR);
+
+			/* estimate iteration count */
+			iter_cnt = (REC_BENCH_MEMORY);
+			iter_cnt /= zio_bench.io_size;
+
+			/* calculate how many bad columns there are */
+			nbad = MIN(3, raidz_ncols(rm_bench) -
+			    raidz_parity(rm_bench));
+
+			getrusage(RUSAGE_THREAD, &start);
+			for (iter = 0; iter < iter_cnt; iter++)
+				vdev_raidz_reconstruct(rm_bench, tgt[fn], nbad);
+			getrusage(RUSAGE_THREAD, &stop);
+
+			elapsed = get_time_diff(&start, &stop);
+			disksize = (1ULL << ds) / rto_opts.rto_dcols;
+			d_bw = (double)iter_cnt * (double)(disksize);
+			d_bw /= (1024.0 * 1024.0 * elapsed);
+
+			LOG(D_ALL, "%10s, %8s, %zu, %10llu, %lf, %lf, %u\n",
+			    impl,
+			    raidz_rec_name[fn],
+			    rto_opts.rto_dcols,
+			    (1ULL<<ds),
+			    d_bw,
+			    d_bw * (double)ncols,
+			    (unsigned) iter_cnt);
+
+			vdev_raidz_map_free(rm_bench);
+		}
+	}
+}
+
+void
+run_rec_bench(void)
+{
+	char **impl_name;
+
+	LOG(D_INFO, DBLSEP "\nBenchmarking data reconstruction...\n\n");
+	LOG(D_ALL, "impl, math, dcols, iosize, disk_bw, total_bw, iter\n");
+
+	for (impl_name = (char **)raidz_impl_names; *impl_name != NULL;
+	    impl_name++) {
+
+		if (vdev_raidz_impl_set(*impl_name) != 0)
+			continue;
+
+		run_rec_bench_impl(*impl_name);
+	}
+}
+
+void
+run_raidz_benchmark(void)
+{
+	bench_init_raidz_map();
+
+	run_gen_bench();
+	run_rec_bench();
+
+	bench_fini_raidz_maps();
+}