engines: add engine for file stat

[fio.git] / engines / filestat.c

diff --git a/engines/filestat.c b/engines/filestat.c
new file mode 100644 (file)
index 0000000..9a394fe
--- /dev/null
+++ b/engines/filestat.c
@@ -0,0 +1,116 @@
+/*
+ * 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\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 int stat_invalidate(struct thread_data *td, struct fio_file *f)
+{
+       /* do nothing because file not opened */
+       return 0;
+}
+
+static struct ioengine_ops ioengine = {
+       .name           = "filestat",
+       .version        = FIO_IOOPS_VERSION,
+       .init           = init,
+       .cleanup        = cleanup,
+       .queue          = queue_io,
+       .invalidate     = stat_invalidate,
+       .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_filestat_register(void)
+{
+       register_ioengine(&ioengine);
+}
+
+static void fio_exit fio_filestat_unregister(void)
+{
+       unregister_ioengine(&ioengine);
+}