ioengines: don't record issue_time if ioengines already do it

io_uring, io_uring_cmd, and libaio record issue_time inside the ioengine
code when their commit functions are called. So we don't need to record
issue_time again for these ioengines in td_io_queue.

If we do fill issue_time twice, then mean(slat) + mean(clat) !=
mean(lat):

user@ubuntu:~/fio-dev$ fio-canonical/fio --name=test --ioengine=io_uring --number_ios=1 --rw=randread --size=1M
test: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=1
fio-3.30-48-g26fa
Starting 1 process

test: (groupid=0, jobs=1): err= 0: pid=172145: Mon Jun  6 16:12:42 2022
  read: IOPS=1000, BW=4000KiB/s (4096kB/s)(4096B/1msec)
    slat (nsec): min=61424, max=61424, avg=61424.00, stdev= 0.00
    clat (nsec): min=242709, max=242709, avg=242709.00, stdev= 0.00
     lat (nsec): min=308346, max=308346, avg=308346.00, stdev= 0.00

61424 + 242709 = 304133 != 308346

If we fill issue_time only once, then the equality will hold (as it
should):

user@ubuntu:~/fio-dev$ fio-latency/fio --name=test --ioengine=io_uring --number_ios=1 --rw=randread --size=1M
test: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=1
fio-3.30-48-g26fa-dirty
Starting 1 process

test: (groupid=0, jobs=1): err= 0: pid=172220: Mon Jun  6 16:12:47 2022
  read: IOPS=1000, BW=4000KiB/s (4096kB/s)(4096B/1msec)
    slat (nsec): min=53701, max=53701, avg=53701.00, stdev= 0.00
    clat (nsec): min=259566, max=259566, avg=259566.00, stdev= 0.00
     lat (nsec): min=313267, max=313267, avg=313267.00, stdev= 0.00

53701 + 259566 = 313267

Signed-off-by: Vincent Fu <vincent.fu@samsung.com>
Link: https://lore.kernel.org/r/20220614155822.307771-3-vincent.fu@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/engines/io_uring.c b/engines/io_uring.c
index cceafe6924a8b69d85075c7ec2fa473874ecb93c..474d215c277313ee9e94902a79e5dc613507113d 100644 (file)
--- a/engines/io_uring.c
+++ b/engines/io_uring.c
@@ -1191,7 +1191,8 @@ static int fio_ioring_cmd_get_max_open_zones(struct thread_data *td,
 static struct ioengine_ops ioengine_uring = {
        .name                   = "io_uring",
        .version                = FIO_IOOPS_VERSION,
-       .flags                  = FIO_ASYNCIO_SYNC_TRIM | FIO_NO_OFFLOAD,
+       .flags                  = FIO_ASYNCIO_SYNC_TRIM | FIO_NO_OFFLOAD |
+                                       FIO_ASYNCIO_SETS_ISSUE_TIME,
        .init                   = fio_ioring_init,
        .post_init              = fio_ioring_post_init,
        .io_u_init              = fio_ioring_io_u_init,
@@ -1211,7 +1212,9 @@ static struct ioengine_ops ioengine_uring = {
 static struct ioengine_ops ioengine_uring_cmd = {
        .name                   = "io_uring_cmd",
        .version                = FIO_IOOPS_VERSION,
-       .flags                  = FIO_ASYNCIO_SYNC_TRIM | FIO_NO_OFFLOAD | FIO_MEMALIGN | FIO_RAWIO,
+       .flags                  = FIO_ASYNCIO_SYNC_TRIM | FIO_NO_OFFLOAD |
+                                       FIO_MEMALIGN | FIO_RAWIO |
+                                       FIO_ASYNCIO_SETS_ISSUE_TIME,
        .init                   = fio_ioring_init,
        .post_init              = fio_ioring_cmd_post_init,
        .io_u_init              = fio_ioring_io_u_init,

diff --git a/engines/libaio.c b/engines/libaio.c
index 9c278d060b218617d0ab89aa5285a1e010507661..da5279f48501919f6b8d0a72054255f2e10a2a2f 100644 (file)
--- a/engines/libaio.c
+++ b/engines/libaio.c
@@ -511,7 +511,8 @@ static int fio_libaio_init(struct thread_data *td)
 FIO_STATIC struct ioengine_ops ioengine = {
        .name                   = "libaio",
        .version                = FIO_IOOPS_VERSION,
-       .flags                  = FIO_ASYNCIO_SYNC_TRIM,
+       .flags                  = FIO_ASYNCIO_SYNC_TRIM |
+                                       FIO_ASYNCIO_SETS_ISSUE_TIME,
        .init                   = fio_libaio_init,
        .post_init              = fio_libaio_post_init,
        .prep                   = fio_libaio_prep,

diff --git a/ioengines.c b/ioengines.c
index 280da3c8262457451d776b67ac34093ed2c3c24b..e4ad698c6775d0c57b4689f99825da396338ec1d 100644 (file)
--- a/ioengines.c
+++ b/ioengines.c
@@ -442,7 +442,8 @@ enum fio_q_status td_io_queue(struct thread_data *td, struct io_u *io_u)
 
        if (!td_ioengine_flagged(td, FIO_SYNCIO) &&
                !async_ioengine_sync_trim(td, io_u)) {
-               if (fio_fill_issue_time(td))
+               if (fio_fill_issue_time(td) &&
+                       !td_ioengine_flagged(td, FIO_ASYNCIO_SETS_ISSUE_TIME))
                        fio_gettime(&io_u->issue_time, NULL);
 
                /*

diff --git a/ioengines.h b/ioengines.h
index acdb0071f52de85e67d462b1e2fb4773e54970fb..fafa1e48186c15f2010f68310122127616651aad 100644 (file)
--- a/ioengines.h
+++ b/ioengines.h
@@ -83,6 +83,8 @@ enum fio_ioengine_flags {
        FIO_ASYNCIO_SYNC_TRIM
                        = 1 << 14,      /* io engine has async ->queue except for trim */
        FIO_NO_OFFLOAD  = 1 << 15,      /* no async offload */
+       FIO_ASYNCIO_SETS_ISSUE_TIME
+                       = 1 << 16,      /* async ioengine with commit function that sets issue_time */
 };
 
 /*