From e1bcd541f63f9029f6c50116831303ad06292edc Mon Sep 17 00:00:00 2001
From: Song Liu <songliubraving@fb.com>
Date: Sun, 17 May 2020 22:39:49 -0700
Subject: [PATCH] Add option latency_run to continue enable latency_target
Currently, latency_target run will exist once fio find the highest queue
depth that meets latency_target. Add option latency_run. If set, fio will
continue running and try to meet latency_target by adusting queue depth.
Signed-off-by: Song Liu <songliubraving@fb.com>
---
HOWTO | 7 +++++++
cconv.c | 2 ++
fio.1 | 5 +++++
fio.h | 1 +
io_u.c | 18 +++++++++++++++++-
options.c | 10 ++++++++++
server.h | 2 +-
thread_options.h | 2 ++
8 files changed, 45 insertions(+), 2 deletions(-)
diff --git a/HOWTO b/HOWTO
index 430c7b62..f0b4ffe4 100644
--- a/HOWTO
+++ b/HOWTO
@@ -2551,6 +2551,13 @@ I/O latency
defaults to 100.0, meaning that all I/Os must be equal or below to the value
set by :option:`latency_target`.
+.. option:: latency_run=bool
+
+ Used with :option:`latency_target`. If false (default), fio will find
+ the highest queue depth that meets :option:`latency_target` and exit. If
+ true, fio will continue running and try to meet :option:`latency_target`
+ by adjusting queue depth.
+
.. option:: max_latency=time
If set, fio will exit the job with an ETIMEDOUT error if it exceeds this
diff --git a/cconv.c b/cconv.c
index 48218dc4..449bcf7b 100644
--- a/cconv.c
+++ b/cconv.c
@@ -288,6 +288,7 @@ void convert_thread_options_to_cpu(struct thread_options *o,
o->latency_window = le64_to_cpu(top->latency_window);
o->max_latency = le64_to_cpu(top->max_latency);
o->latency_percentile.u.f = fio_uint64_to_double(le64_to_cpu(top->latency_percentile.u.i));
+ o->latency_run = le32_to_cpu(top->latency_run);
o->compress_percentage = le32_to_cpu(top->compress_percentage);
o->compress_chunk = le32_to_cpu(top->compress_chunk);
o->dedupe_percentage = le32_to_cpu(top->dedupe_percentage);
@@ -487,6 +488,7 @@ void convert_thread_options_to_net(struct thread_options_pack *top,
top->latency_window = __cpu_to_le64(o->latency_window);
top->max_latency = __cpu_to_le64(o->max_latency);
top->latency_percentile.u.i = __cpu_to_le64(fio_double_to_uint64(o->latency_percentile.u.f));
+ top->latency_run = __cpu_to_le32(o->latency_run);
top->compress_percentage = cpu_to_le32(o->compress_percentage);
top->compress_chunk = cpu_to_le32(o->compress_chunk);
top->dedupe_percentage = cpu_to_le32(o->dedupe_percentage);
diff --git a/fio.1 b/fio.1
index a2379f98..3a7a359b 100644
--- a/fio.1
+++ b/fio.1
@@ -2275,6 +2275,11 @@ The percentage of I/Os that must fall within the criteria specified by
defaults to 100.0, meaning that all I/Os must be equal or below to the value
set by \fBlatency_target\fR.
.TP
+.BI latency_run \fR=\fPbool
+Used with \fBlatency_target\fR. If false (default), fio will find the highest
+queue depth that meets \fBlatency_target\fR and exit. If true, fio will continue
+running and try to meet \fBlatency_target\fR by adjusting queue depth.
+.TP
.BI max_latency \fR=\fPtime
If set, fio will exit the job with an ETIMEDOUT error if it exceeds this
maximum latency. When the unit is omitted, the value is interpreted in
diff --git a/fio.h b/fio.h
index bbf057c1..7610026d 100644
--- a/fio.h
+++ b/fio.h
@@ -377,6 +377,7 @@ struct thread_data {
unsigned int latency_qd_high;
unsigned int latency_qd_low;
unsigned int latency_failed;
+ unsigned int latency_stable_count;
uint64_t latency_ios;
int latency_end_run;
diff --git a/io_u.c b/io_u.c
index aa8808b8..ae1438fd 100644
--- a/io_u.c
+++ b/io_u.c
@@ -1391,6 +1391,7 @@ static bool __lat_target_failed(struct thread_data *td)
td->latency_qd_low--;
td->latency_qd = (td->latency_qd + td->latency_qd_low) / 2;
+ td->latency_stable_count = 0;
dprint(FD_RATE, "Ramped down: %d %d %d\n", td->latency_qd_low, td->latency_qd, td->latency_qd_high);
@@ -1440,6 +1441,21 @@ static void lat_target_success(struct thread_data *td)
td->latency_qd_low = td->latency_qd;
+ if (td->latency_qd + 1 == td->latency_qd_high) {
+ /*
+ * latency_qd will not incease on lat_target_success(), so
+ * called stable. If we stick with this queue depth, the
+ * final latency is likely lower than latency_target. Fix
+ * this by increasing latency_qd_high slowly. Use a naive
+ * heuristic here. If we get lat_target_success() 3 times
+ * in a row, increase latency_qd_high by 1.
+ */
+ if (++td->latency_stable_count >= 3) {
+ td->latency_qd_high++;
+ td->latency_stable_count = 0;
+ }
+ }
+
/*
* If we haven't failed yet, we double up to a failing value instead
* of bisecting from highest possible queue depth. If we have set
@@ -1459,7 +1475,7 @@ static void lat_target_success(struct thread_data *td)
* Same as last one, we are done. Let it run a latency cycle, so
* we get only the results from the targeted depth.
*/
- if (td->latency_qd == qd) {
+ if (!o->latency_run && td->latency_qd == qd) {
if (td->latency_end_run) {
dprint(FD_RATE, "We are done\n");
td->done = 1;
diff --git a/options.c b/options.c
index b18cea33..da401aed 100644
--- a/options.c
+++ b/options.c
@@ -3672,6 +3672,16 @@ struct fio_option fio_options[FIO_MAX_OPTS] = {
.category = FIO_OPT_C_IO,
.group = FIO_OPT_G_LATPROF,
},
+ {
+ .name = "latency_run",
+ .lname = "Latency Run",
+ .type = FIO_OPT_BOOL,
+ .off1 = offsetof(struct thread_options, latency_run),
+ .help = "Keep adjusting queue depth to match latency_target",
+ .def = "0",
+ .category = FIO_OPT_C_IO,
+ .group = FIO_OPT_G_LATPROF,
+ },
{
.name = "invalidate",
.lname = "Cache invalidate",
diff --git a/server.h b/server.h
index 279b6917..de01a5c8 100644
--- a/server.h
+++ b/server.h
@@ -48,7 +48,7 @@ struct fio_net_cmd_reply {
};
enum {
- FIO_SERVER_VER = 82,
+ FIO_SERVER_VER = 83,
FIO_SERVER_MAX_FRAGMENT_PDU = 1024,
FIO_SERVER_MAX_CMD_MB = 2048,
diff --git a/thread_options.h b/thread_options.h
index c78ed43d..09ccd5b2 100644
--- a/thread_options.h
+++ b/thread_options.h
@@ -324,6 +324,7 @@ struct thread_options {
unsigned long long latency_target;
unsigned long long latency_window;
fio_fp64_t latency_percentile;
+ uint32_t latency_run;
unsigned int sig_figs;
@@ -612,6 +613,7 @@ struct thread_options_pack {
uint64_t latency_window;
uint64_t max_latency;
fio_fp64_t latency_percentile;
+ uint32_t latency_run;
uint32_t sig_figs;
--
2.17.0