flashbench: implement write opcodes in vm

This makes it possible to use three kinds of
write operations, writing zero-, one- or
somwhat random contents. Many media have different
characteristics depending on the kind of content.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

2 files changed, 55 insertions, 16 deletions

diff --git a/dev.c b/dev.c
index 6bd209d..c5c4088 100644
--- a/dev.c
+++ b/dev.c
@@ -19,6 +19,8 @@
 
 #include "dev.h"
 
+#define MAX_BUFSIZE (64 * 1024 * 1024)
+
 static inline long long time_to_ns(struct timespec *ts)
 {
 	return ts->tv_sec * 1000 * 1000 * 1000 + ts->tv_nsec;
@@ -33,46 +35,49 @@ static long long get_ns(void)
 
 long long time_read(struct device *dev, off_t pos, size_t size)
 {
-	static char readbuf[64 * 1024 * 1024] __attribute__((aligned(4096)));
 	long long now = get_ns();
 	ssize_t ret;
 
-	if (size > sizeof(readbuf))
+	if (size > MAX_BUFSIZE)
 		return -ENOMEM;
 
 	do {
-		ret = pread(dev->fd, readbuf, size, pos % dev->size);
+		ret = pread(dev->fd, dev->readbuf, size, pos % dev->size);
 		if (ret > 0) {
 			size -= ret;
 			pos += ret;
 		}
 	} while (ret > 0 || errno == -EAGAIN);
 
-	if (ret)
-		return -errno;
+	if (ret) {
+		fprintf(stderr, "fd %d buf %p size %ld pos %ld\n", dev->fd, dev->readbuf, size, pos % dev->size);
+		perror("time_read");
+		return 0;
+	}
 
 	return get_ns() - now;
 }
 
 long long time_write(struct device *dev, off_t pos, size_t size, enum writebuf which)
 {
-	static char writebuf[64 * 1024 * 1024] __attribute__((aligned(4096)));
 	long long now = get_ns();
 	ssize_t ret;
 
-	if (size > sizeof(writebuf))
+	if (size > MAX_BUFSIZE)
 		return -ENOMEM;
 
 	do {
-		ret = pwrite(dev->fd, writebuf, size, pos % dev->size);
+		ret = pwrite(dev->fd, dev->writebuf[which], size, pos % dev->size);
 		if (ret > 0) {
 			size -= ret;
 			pos += ret;
 		}
 	} while (ret > 0 || errno == -EAGAIN);
 
-	if (ret)
-		return -errno;
+	if (ret) {
+		perror("time_write");
+		return 0;
+	}
 
 	return get_ns() - now;
 }
@@ -91,6 +96,7 @@ static void set_rtprio(void)
 
 int setup_dev(struct device *dev, const char *filename)
 {
+	int i, err;
 	set_rtprio();
 
 	dev->fd = open(filename, O_RDWR | O_DIRECT | O_SYNC | O_NOATIME);
@@ -105,8 +111,19 @@ int setup_dev(struct device *dev, const char *filename)
 		return -errno;
 	}
 
-	return 0;
-}
-
+	err = posix_memalign(&dev->readbuf,		4096, MAX_BUFSIZE);
+	if (err) return -err;
+	err = posix_memalign(&dev->writebuf[WBUF_ZERO], 4096, MAX_BUFSIZE);
+	if (err) return -err;
+	err = posix_memalign(&dev->writebuf[WBUF_ONE],  4096, MAX_BUFSIZE);
+	if (err) return -err;
+	err = posix_memalign(&dev->writebuf[WBUF_RAND], 4096, MAX_BUFSIZE);
+	if (err) return -err;
 
+	memset(dev->writebuf[WBUF_ZERO], 0, MAX_BUFSIZE);
+	memset(dev->writebuf[WBUF_ONE], 0xff, MAX_BUFSIZE);
+	for (i = 0; i < MAX_BUFSIZE; i+=256)
+		memset(dev->writebuf[WBUF_RAND] + i, (i & 0xff), 256);
 
+	return 0;
+}
diff --git a/vm.c b/vm.c
index 36fb042..2bcf34c 100644
--- a/vm.c
+++ b/vm.c
@@ -168,6 +168,28 @@ static struct operation *do_read(struct operation *op, struct device *dev,
 	return op+1;
 }
 
+static struct operation *do_write(struct operation *op, struct device *dev,
+		 off_t off, off_t max, size_t len)
+{
+	enum writebuf writebuf;
+	switch (op->code) {
+	case O_WRITE_ZERO:
+		writebuf = WBUF_ZERO;
+		break;
+	case O_WRITE_ONE:
+		writebuf = WBUF_ONE;
+		break;
+	case O_WRITE_RAND:
+		writebuf = WBUF_RAND;
+		break;
+	default:
+		return NULL;
+	}
+	op->result.l = time_write(dev, off, len, writebuf);
+	op->r_type = R_NS;
+	return op+1;
+}
+
 static struct operation *length_or_offs(struct operation *op, struct device *dev,
 		 off_t off, off_t max, size_t len)
 {
@@ -482,9 +504,9 @@ static struct operation *drop(struct operation *op, struct device *dev,
 static struct syntax syntax[] = {
 	{ O_END,	"END",		nop,		},
 	{ O_READ,	"READ",		do_read,	},
-	{ O_WRITE_ZERO,	"WRITE_ZERO",	nop,		},
-	{ O_WRITE_ONE,	"WRITE_ONE",	nop,		},
-	{ O_WRITE_RAND,	"WRITE_RAND",	nop,		},
+	{ O_WRITE_ZERO,	"WRITE_ZERO",	do_write,	},
+	{ O_WRITE_ONE,	"WRITE_ONE",	do_write,	},
+	{ O_WRITE_RAND,	"WRITE_RAND",	do_write,	},
 	{ O_ERASE,	"ERASE",	nop,		},
 	{ O_LENGTH,	"LENGTH",	length_or_offs	},
 	{ O_OFFSET,	"OFFSET",	length_or_offs,	},