This adds a fragread command in f2fs_io, which is able to measure the
read performance on fragmented data buffer.
Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
tools/f2fs_io/f2fs_io.c | 114 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)
diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
index 44d389dbd771..57a931d5769c 100644
--- a/tools/f2fs_io/f2fs_io.c
+++ b/tools/f2fs_io/f2fs_io.c
@@ -1005,6 +1005,119 @@ static void do_read(int argc, char **argv, const struct
cmd_desc *cmd)
exit(0);
}
+#define fragread_desc "read data with a fragmented buffer from file"
+#define fragread_help \
+"f2fs_io fragread [chunk_size in 4kb] [offset in chunk_size] [count] [advice]
[file_path]\n\n" \
+"Read data in file_path and print nbytes\n" \
+"advice can be\n" \
+" 1 : set sequential|willneed\n" \
+" 0 : none\n" \
+
+#ifndef PAGE_SIZE
+#define PAGE_SIZE sysconf(_SC_PAGESIZE)
+#endif
+#define ALLOC_SIZE (2 * 1024 * 1024 - 4 * 1024) // 2MB - 4KB
+
+static void do_fragread(int argc, char **argv, const struct cmd_desc *cmd)
+{
+ u64 buf_size = 0, ret = 0, read_cnt = 0;
+ u64 offset;
+ char *buf = NULL;
+ uintptr_t idx, ptr;
+ unsigned bs, count, i;
+ u64 total_time = 0;
+ int flags = 0, alloc_count = 0;
+ void *mem_hole, **mem_holes;
+ int fd, advice;
+
+ if (argc != 6) {
+ fputs("Excess arguments\n\n", stderr);
+ fputs(cmd->cmd_help, stderr);
+ exit(1);
+ }
+
+ bs = atoi(argv[1]);
+ if (bs > 256 * 1024)
+ die("Too big chunk size - limit: 1GB");
+ buf_size = bs * F2FS_DEFAULT_BLKSIZE;
+
+ offset = atoi(argv[2]) * buf_size;
+ count = atoi(argv[3]);
+ advice = atoi(argv[4]);
+ mem_holes = xmalloc(sizeof(void *) * (buf_size / PAGE_SIZE));
+
+ /* 1. Allocate the buffer using mmap. */
+ buf = mmap(NULL, buf_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+ /* 2. Loop and touch each page. */
+ for (idx = (uintptr_t)buf; idx < (uintptr_t)buf + buf_size;
+ idx += PAGE_SIZE)
+ {
+ /* Touch the current page. */
+ volatile char *page = (volatile char *)idx;
+ *page;
+
+ /* 3. Allocate (2M - 4K) memory using mmap and touch all of it.
*/
+ mem_hole = mmap(NULL, ALLOC_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (mem_hole == MAP_FAILED)
+ die_errno("map failed");
+
+ /* Store the allocated memory pointer. */
+ mem_holes[alloc_count++] = mem_hole;
+
+ /* Touch all allocated memory. */
+ for (ptr = (uintptr_t)mem_hole;
+ ptr < (uintptr_t)mem_hole + ALLOC_SIZE;
+ ptr += PAGE_SIZE) {
+ volatile char *alloc_page = (volatile char *)ptr;
+ *alloc_page;
+ }
+ }
+ printf("Touched allocated memory: count = %u\n", alloc_count);
+ printf(" - allocated memory: = ");
+ for (idx = 0; idx < 5; idx++)
+ printf(" %p", mem_holes[idx]);
+ printf("\n");
+
+ /* Pin the pages. */
+ if (mlock(buf, buf_size))
+ die_errno("mlock failed");
+
+ fd = xopen(argv[5], O_RDONLY | flags, 0);
+
+ if (advice) {
+ if (posix_fadvise(fd, 0, F2FS_DEFAULT_BLKSIZE,
+ POSIX_FADV_SEQUENTIAL) != 0)
+ die_errno("fadvise failed");
+ if (posix_fadvise(fd, 0, F2FS_DEFAULT_BLKSIZE,
+ POSIX_FADV_WILLNEED) != 0)
+ die_errno("fadvise failed");
+ printf("fadvise SEQUENTIAL|WILLNEED to a file: %s\n", argv[5]);
+ }
+
+ total_time = get_current_us();
+
+ for (i = 0; i < count; i++) {
+ ret = pread(fd, buf, buf_size, offset + buf_size * i);
+ if (ret != buf_size) {
+ printf("pread expected: %"PRIu64", readed: %"PRIu64"\n",
+ buf_size, ret);
+ if (ret > 0)
+ read_cnt += ret;
+ break;
+ }
+
+ read_cnt += ret;
+ }
+ printf("Fragmented_Read %"PRIu64" bytes total_time = %"PRIu64" us, BW =
%.Lf MB/s\n",
+ read_cnt, get_current_us() - total_time,
+ ((long double)read_cnt / (get_current_us() - total_time)));
+ printf("\n");
+ exit(0);
+}
+
#define randread_desc "random read data from file"
#define randread_help \
"f2fs_io randread [chunk_size in 4kb] [count] [IO] [advise] [file_path]\n\n"
\
@@ -1989,6 +2102,7 @@ const struct cmd_desc cmd_list[] = {
CMD(write_advice),
CMD(read),
CMD(randread),
+ CMD(fragread),
CMD(fiemap),
CMD(gc_urgent),
CMD(defrag_file),
--
2.49.0.rc1.451.g8f38331e32-goog
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