Sorry I missed this the first time round. Some comments below:
On Wed, 4 Dec 2019 at 10:09, <Friendy.Su@xxxxxxxx> wrote:
>
> 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);
Don't you always want this on?
> +
> + ret = stat(f->file_name, &statbuf);
Will this work on Windows too?
> +
> + 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.
Should your engine print a message about this on startup if it finds
that it's set?
> +# '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
>
Could you update the documentation (rst file HOWTO and man page fio.1)
with a description of how to use your ioengine?
--
Sitsofe | http://sucs.org/~sits/
