>From 1ee08ca5ed9d3c852c9b536dae719b4a49e7524e Mon Sep 17 00:00:00 2001
From: friendy-su <friendy.su@xxxxxxxx>
Date: Mon, 2 Dec 2019 18:25:05 +0800
Subject: [PATCH] engines: add engine for file stat
This engine is to measure performance of accessing file's meta data.
This is for the actual access pattern which does not do real IO, but
just look up the file and get file's attribute.
Signed-off-by: friendy-su <friendy.su@xxxxxxxx>
---
Makefile | 2 +-
engines/filestat.c | 109 +++++++++++++++++++++++++++++++++
examples/filestat-ioengine.fio | 20 ++++++
3 files changed, 130 insertions(+), 1 deletion(-)
create mode 100644 engines/filestat.c
create mode 100644 examples/filestat-ioengine.fio
diff --git a/Makefile b/Makefile
index 7aab6abd..ab85ceac 100644
--- a/Makefile
+++ b/Makefile
@@ -45,7 +45,7 @@ SOURCE := $(sort $(patsubst $(SRCDIR)/%,%,$(wildcard $(SRCDIR)/crc/*.c)) \
pshared.c options.c \
smalloc.c filehash.c profile.c debug.c engines/cpu.c \
engines/mmap.c engines/sync.c engines/null.c engines/net.c \
- engines/ftruncate.c engines/filecreate.c \
+ engines/ftruncate.c engines/filecreate.c engines/filestat.c \
server.c client.c iolog.c backend.c libfio.c flow.c cconv.c \
gettime-thread.c helpers.c json.c idletime.c td_error.c \
profiles/tiobench.c profiles/act.c io_u_queue.c filelock.c \
diff --git a/engines/filestat.c b/engines/filestat.c
new file mode 100644
index 00000000..9c6636a8
--- /dev/null
+++ b/engines/filestat.c
@@ -0,0 +1,109 @@
+/*
+ * filestat engine
+ *
+ * IO engine that doesn't do any IO, just stat files and tracks the latency
+ * of the file stat.
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include "../fio.h"
+
+struct fc_data {
+ enum fio_ddir stat_ddir;
+};
+
+static int stat_file(struct thread_data *td, struct fio_file *f)
+{
+ struct timespec start;
+ int do_lat = !td->o.disable_lat;
+ struct stat statbuf;
+ int ret;
+
+ dprint(FD_FILE, "fd stat %s\n", f->file_name);
+
+ if (f->filetype != FIO_TYPE_FILE) {
+ log_err("fio: only files are supported fallocate \n");
+ return 1;
+ }
+ if (!strcmp(f->file_name, "-")) {
+ log_err("fio: can't read/write to stdin/out\n");
+ return 1;
+ }
+
+ if (do_lat)
+ fio_gettime(&start, NULL);
+
+ ret = stat(f->file_name, &statbuf);
+
+ if (ret == -1) {
+ char buf[FIO_VERROR_SIZE];
+ int e = errno;
+
+ snprintf(buf, sizeof(buf), "stat(%s)", f->file_name);
+ td_verror(td, e, buf);
+ return 1;
+ }
+
+ if (do_lat) {
+ struct fc_data *data = td->io_ops_data;
+ uint64_t nsec;
+
+ nsec = ntime_since_now(&start);
+ add_clat_sample(td, data->stat_ddir, nsec, 0, 0);
+ }
+
+ return 0;
+}
+
+static enum fio_q_status queue_io(struct thread_data *td, struct io_u fio_unused *io_u)
+{
+ return FIO_Q_COMPLETED;
+}
+
+static int init(struct thread_data *td)
+{
+ struct fc_data *data;
+
+ data = calloc(1, sizeof(*data));
+
+ if (td_read(td))
+ data->stat_ddir = DDIR_READ;
+ else if (td_write(td))
+ data->stat_ddir = DDIR_WRITE;
+
+ td->io_ops_data = data;
+ return 0;
+}
+
+static void cleanup(struct thread_data *td)
+{
+ struct fc_data *data = td->io_ops_data;
+
+ free(data);
+}
+
+static struct ioengine_ops ioengine = {
+ .name = "filestat",
+ .version = FIO_IOOPS_VERSION,
+ .init = init,
+ .cleanup = cleanup,
+ .queue = queue_io,
+ .get_file_size = generic_get_file_size,
+ .open_file = stat_file,
+ .flags = FIO_SYNCIO | FIO_FAKEIO |
+ FIO_NOSTATS | FIO_NOFILEHASH,
+};
+
+static void fio_init fio_filecreate_register(void)
+{
+ register_ioengine(&ioengine);
+}
+
+static void fio_exit fio_filecreate_unregister(void)
+{
+ unregister_ioengine(&ioengine);
+}
diff --git a/examples/filestat-ioengine.fio b/examples/filestat-ioengine.fio
new file mode 100644
index 00000000..9a771160
--- /dev/null
+++ b/examples/filestat-ioengine.fio
@@ -0,0 +1,20 @@
+# Example filestat job
+
+# 'filestat' engine only do 'stat(filename)', file will not be open().
+# 'invalidate' should be set to 0 since file will not be open(), posix_fadvise(fd,....) will fail.
+# 'filesize' must be set, then files will be created at setup stage.
+
+[global]
+ioengine=filestat
+numjobs=1
+filesize=4k
+invalidate=0
+nrfiles=200
+
+[t0]
+[t1]
+[t2]
+[t3]
+[t4]
+[t5]
+
--
2.17.1
