Fix end-of-job slowdown for random IO with a random map

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/arch/arch-x86_64.h b/arch/arch-x86_64.h
index 6dbeee06a6ed2999de25909287b6431828b30107..f2dcf497f63ec89ca88c8c3817de407c7a1d80c9 100644 (file)
--- a/arch/arch-x86_64.h
+++ b/arch/arch-x86_64.h
@@ -33,9 +33,9 @@
 #define read_barrier() __asm__ __volatile__("lfence":::"memory")
 #define write_barrier()        __asm__ __volatile__("sfence":::"memory")
 
-static inline unsigned int arch_ffz(unsigned int bitmask)
+static inline unsigned long arch_ffz(unsigned long bitmask)
 {
-       __asm__("bsfl %1,%0" :"=r" (bitmask) :"r" (~bitmask));
+       __asm__("bsf %1,%0" :"=r" (bitmask) :"r" (~bitmask));
        return bitmask;
 }
 

diff --git a/file.h b/file.h
index 7948a4124caddca07d9ddc88b7166193b6546bce..04c0d4536b4f16aa91ca58609de80c1f973228c7 100644 (file)
--- a/file.h
+++ b/file.h
@@ -96,9 +96,10 @@ struct fio_file {
        /*
         * block map for random io
         */
-       unsigned int *file_map;
+       unsigned long *file_map;
        unsigned int num_maps;
        unsigned int last_free_lookup;
+       unsigned int failed_rands;
 
        int references;
        enum fio_file_flags flags;
@@ -158,11 +159,12 @@ extern void free_release_files(struct thread_data *);
 static inline void fio_file_reset(struct fio_file *f)
 {
        f->last_free_lookup = 0;
+       f->failed_rands = 0;
        f->last_pos = f->file_offset;
        f->last_start = -1ULL;
        f->file_pos = -1ULL;
        if (f->file_map)
-               memset(f->file_map, 0, f->num_maps * sizeof(int));
+               memset(f->file_map, 0, f->num_maps * sizeof(unsigned long));
 }
 
 #endif

diff --git a/filesetup.c b/filesetup.c
index d05050647ddbbcc78b1b22d59c91e8f7444d7b43..0454cc4007936611ac53bad147b7f06b2afd2faa 100644 (file)
--- a/filesetup.c
+++ b/filesetup.c
@@ -812,7 +812,7 @@ int init_random_map(struct thread_data *td)
                                (unsigned long long) td->o.rw_min_bs;
                num_maps = (blocks + BLOCKS_PER_MAP - 1) /
                                (unsigned long long) BLOCKS_PER_MAP;
-               f->file_map = smalloc(num_maps * sizeof(int));
+               f->file_map = smalloc(num_maps * sizeof(unsigned long));
                if (f->file_map) {
                        f->num_maps = num_maps;
                        continue;

diff --git a/fio.h b/fio.h
index d2cca1182b2b40d271caa2f88a766836448be138..08f17331d081ef6e086c34f9615fb6d3dfe8d225 100644 (file)
--- a/fio.h
+++ b/fio.h
@@ -531,7 +531,7 @@ static inline void fio_ro_check(struct thread_data *td, struct io_u *io_u)
        assert(!(io_u->ddir == DDIR_WRITE && !td_write(td)));
 }
 
-#define BLOCKS_PER_MAP         (8 * sizeof(int))
+#define BLOCKS_PER_MAP         (8 * sizeof(unsigned long))
 #define TO_MAP_BLOCK(f, b)     (b)
 #define RAND_MAP_IDX(f, b)     (TO_MAP_BLOCK(f, b) / BLOCKS_PER_MAP)
 #define RAND_MAP_BIT(f, b)     (TO_MAP_BLOCK(f, b) & (BLOCKS_PER_MAP - 1))

diff --git a/io_u.c b/io_u.c
index 1a45706f160556f2c153bf82505370b484d7055e..5a3ca7444946751f4e208a32affdad5fb98051b9 100644 (file)
--- a/io_u.c
+++ b/io_u.c
@@ -30,7 +30,7 @@ static int random_map_free(struct fio_file *f, const unsigned long long block)
 
        dprint(FD_RANDOM, "free: b=%llu, idx=%u, bit=%u\n", block, idx, bit);
 
-       return (f->file_map[idx] & (1 << bit)) == 0;
+       return (f->file_map[idx] & (1UL << bit)) == 0;
 }
 
 /*
@@ -50,8 +50,8 @@ static void mark_random_map(struct thread_data *td, struct io_u *io_u)
        busy_check = !(io_u->flags & IO_U_F_BUSY_OK);
 
        while (nr_blocks) {
-               unsigned int this_blocks, mask;
                unsigned int idx, bit;
+               unsigned long mask, this_blocks;
 
                /*
                 * If we have a mixed random workload, we may
@@ -75,9 +75,9 @@ static void mark_random_map(struct thread_data *td, struct io_u *io_u)
 
                do {
                        if (this_blocks == BLOCKS_PER_MAP)
-                               mask = -1U;
+                               mask = -1UL;
                        else
-                               mask = ((1U << this_blocks) - 1) << bit;
+                               mask = ((1UL << this_blocks) - 1) << bit;
        
                        if (!(f->file_map[idx] & mask))
                                break;
@@ -126,7 +126,7 @@ static unsigned long long last_block(struct thread_data *td, struct fio_file *f,
 static int get_next_free_block(struct thread_data *td, struct fio_file *f,
                               enum fio_ddir ddir, unsigned long long *b)
 {
-       unsigned long long min_bs = td->o.rw_min_bs, lastb;
+       unsigned long long block, min_bs = td->o.rw_min_bs, lastb;
        int i;
 
        lastb = last_block(td, f, ddir);
@@ -134,18 +134,19 @@ static int get_next_free_block(struct thread_data *td, struct fio_file *f,
                return 1;
 
        i = f->last_free_lookup;
-       *b = (i * BLOCKS_PER_MAP);
-       while ((*b) * min_bs < f->real_file_size &&
-               (*b) * min_bs < f->io_size) {
-               if (f->file_map[i] != (unsigned int) -1) {
-                       *b += ffz(f->file_map[i]);
-                       if (*b > lastb)
+       block = i * BLOCKS_PER_MAP;
+       while (block * min_bs < f->real_file_size &&
+               block * min_bs < f->io_size) {
+               if (f->file_map[i] != -1UL) {
+                       block += ffz(f->file_map[i]);
+                       if (block > lastb)
                                break;
                        f->last_free_lookup = i;
+                       *b = block;
                        return 0;
                }
 
-               *b += BLOCKS_PER_MAP;
+               block += BLOCKS_PER_MAP;
                i++;
        }
 
@@ -163,6 +164,9 @@ static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
        if (!lastb)
                return 1;
 
+       if (f->failed_rands >= 200)
+               goto ffz;
+
        do {
                r = os_random_long(&td->random_state);
                dprint(FD_RANDOM, "off rand %llu\n", r);
@@ -172,18 +176,21 @@ static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
                 * if we are not maintaining a random map, we are done.
                 */
                if (!file_randommap(td, f))
-                       return 0;
+                       goto ret_good;
 
                /*
                 * calculate map offset and check if it's free
                 */
                if (random_map_free(f, *b))
-                       return 0;
+                       goto ret_good;
 
                dprint(FD_RANDOM, "get_next_rand_offset: offset %llu busy\n",
                                                                        *b);
        } while (--loops);
 
+       if (!f->failed_rands++)
+               f->last_free_lookup = 0;
+
        /*
         * we get here, if we didn't suceed in looking up a block. generate
         * a random start offset into the filemap, and find the first free
@@ -194,7 +201,7 @@ static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
                f->last_free_lookup = (f->num_maps - 1) *
                                        (r / (OS_RAND_MAX + 1.0));
                if (!get_next_free_block(td, f, ddir, b))
-                       return 0;
+                       goto ret;
 
                r = os_random_long(&td->random_state);
        } while (--loops);
@@ -203,7 +210,15 @@ static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
         * that didn't work either, try exhaustive search from the start
         */
        f->last_free_lookup = 0;
+ffz:
+       if (!get_next_free_block(td, f, ddir, b))
+               return 0;
+       f->last_free_lookup = 0;
        return get_next_free_block(td, f, ddir, b);
+ret_good:
+       f->failed_rands = 0;
+ret:
+       return 0;
 }
 
 static int get_next_rand_block(struct thread_data *td, struct fio_file *f,

diff --git a/lib/ffz.h b/lib/ffz.h
index e17a2e9c0a1e7cd60f3e99b8989ecc61bebed806..eef612d1a136106feacc4d65939da21f3fcefa26 100644 (file)
--- a/lib/ffz.h
+++ b/lib/ffz.h
@@ -1,10 +1,16 @@
 #ifndef FIO_FFZ_H
 #define FIO_FFZ_H
 
-static inline int __ffs(int word)
+static inline int __ffs(unsigned long word)
 {
        int r = 0;
 
+#if BITS_PER_LONG == 64
+       if ((word & 0xffffffff) == 0) {
+               r += 32;
+               word >>= 32;
+       }
+#endif
        if (!(word & 0xffff)) {
                word >>= 16;
                r += 16;
@@ -29,7 +35,7 @@ static inline int __ffs(int word)
        return r;
 }
 
-static inline int ffz(unsigned int bitmask)
+static inline int ffz(unsigned long bitmask)
 {
        return __ffs(~bitmask);
 }