Fix read/write mix and different levels of randomness
Stephen reports:
When using fio configuration below:
[global]
ioengine=libaio
direct=1
runtime=600
bs=32k
iodepth=8
rw=randrw
rwmixread=80
percentage_random=100,0
[drive1]
filename=/dev/sda
I am expecting to see 80% reads, 20% writes where all reads are random
and all writes are sequential. I captured a bus trace of traffic to the
disk and the bus trace reflected as much with one issue. The write
commands are essentially random. Each write begins at a new random LBA.
If 2 or more writes occur in a row, the LBA's are sequential based on
the block size BUT I feel the heart of this feature would be to emulate
a large file write during random access. With that in mind would it be
possible for sequential reads or writes within mixed sequential/random
workload to remember the last LBA accessed? In this scenario the writes
would still only take up 20% of the workload but when a write did occur
it should be the next sequential step from the last write.
-----
This is due to the fact that fio tracks last start/end on a unified
basis, not per read/write/trim direction. Fix that.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/io_u.c b/io_u.c
index f135908..efbcea9 100644
--- a/io_u.c
+++ b/io_u.c
@@ -249,7 +249,7 @@
}
dprint(FD_IO, "%s: rand offset failed, last=%llu, size=%llu\n",
- f->file_name, (unsigned long long) f->last_pos,
+ f->file_name, (unsigned long long) f->last_pos[ddir],
(unsigned long long) f->real_file_size);
return 1;
}
@@ -261,17 +261,17 @@
assert(ddir_rw(ddir));
- if (f->last_pos >= f->io_size + get_start_offset(td, f) &&
+ if (f->last_pos[ddir] >= f->io_size + get_start_offset(td, f) &&
o->time_based)
- f->last_pos = f->last_pos - f->io_size;
+ f->last_pos[ddir] = f->last_pos[ddir] - f->io_size;
- if (f->last_pos < f->real_file_size) {
+ if (f->last_pos[ddir] < f->real_file_size) {
uint64_t pos;
- if (f->last_pos == f->file_offset && o->ddir_seq_add < 0)
- f->last_pos = f->real_file_size;
+ if (f->last_pos[ddir] == f->file_offset && o->ddir_seq_add < 0)
+ f->last_pos[ddir] = f->real_file_size;
- pos = f->last_pos - f->file_offset;
+ pos = f->last_pos[ddir] - f->file_offset;
if (pos && o->ddir_seq_add) {
pos += o->ddir_seq_add;
@@ -330,8 +330,8 @@
*is_random = 0;
}
} else if (td->o.rw_seq == RW_SEQ_IDENT) {
- if (f->last_start != -1ULL)
- offset = f->last_start - f->file_offset;
+ if (f->last_start[ddir] != -1ULL)
+ offset = f->last_start[ddir] - f->file_offset;
else
offset = 0;
ret = 0;
@@ -743,7 +743,7 @@
*/
if (f->file_offset >= f->real_file_size)
f->file_offset = f->real_file_size - f->file_offset;
- f->last_pos = f->file_offset;
+ f->last_pos[io_u->ddir] = f->file_offset;
td->io_skip_bytes += td->o.zone_skip;
}
@@ -1471,8 +1471,8 @@
goto err_put;
}
- f->last_start = io_u->offset;
- f->last_pos = io_u->offset + io_u->buflen;
+ f->last_start[io_u->ddir] = io_u->offset;
+ f->last_pos[io_u->ddir] = io_u->offset + io_u->buflen;
if (io_u->ddir == DDIR_WRITE) {
if (td->flags & TD_F_REFILL_BUFFERS) {