Add vsync io engine

It uses readv/writev to transfer the data and coalesces adjacent
data into a single system call (emulating queueing).

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/HOWTO b/HOWTO
index a20f7141e63593dd8ed54b696ab80c92e28695a4..3d6b354b87b7df40f723c497ab82b1424cd287f6 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -344,6 +344,8 @@ ioengine=str        Defines how the job issues io to the file. The following
 
                        psync   Basic pread(2) or pwrite(2) io.
 
+                       vsync   Basic readv(2) or writev(3) IO.
+
                        libaio  Linux native asynchronous io.
 
                        posixaio glibc posix asynchronous io.

diff --git a/README b/README
index 4c58d376a5e7c8b6caa7a91a589f3d9b20bef5a3..940839c3892a354da5332b1234dca4d914e1b473 100644 (file)
--- a/README
+++ b/README
@@ -136,14 +136,16 @@ The job file parameters are:
        size=x          Set file size to x bytes (x string can include k/m/g)
        ioengine=x      'x' may be: aio/libaio/linuxaio for Linux aio,
                        posixaio for POSIX aio, sync for regular read/write io,
-                       psync for regular pread/pwrite io, mmap for mmap'ed io,
-                       syslet-rw for syslet driven read/write, splice for using
-                       splice/vmsplice, sgio for direct SG_IO io, net for
-                       network io, or cpuio for a cycler burner load. sgio only
-                       works on Linux on SCSI (or SCSI-like devices, such as
-                       usb-storage or sata/libata driven) devices. Fio also has
-                       a null io engine, which is mainly used for testing fio
-                       itself.
+                       psync for regular pread/pwrite io, vsync for regular
+                       readv/writev (with queuing emulation) mmap for mmap'ed
+                       io, syslet-rw for syslet driven read/write, splice for
+                       using splice/vmsplice, sgio for direct SG_IO io, net
+                       for network io, or cpuio for a cycler burner load. sgio
+                       only works on Linux on SCSI (or SCSI-like devices, such
+                       as usb-storage or sata/libata driven) devices. Fio also
+                       has a null io engine, which is mainly used for testing
+                       fio itself.
+
        iodepth=x       For async io, allow 'x' ios in flight
        overwrite=x     If 'x', layout a write file first.
        nrfiles=x       Spread io load over 'x' number of files per job,

diff --git a/engines/sync.c b/engines/sync.c
index 5e49429306e11c405f6285b95145fd03496ddbb2..505381d4ca942b932d7171393a2dc8f51c558726 100644 (file)
--- a/engines/sync.c
+++ b/engines/sync.c
@@ -13,6 +13,17 @@
 
 #include "../fio.h"
 
+struct syncio_data {
+       struct iovec *iovecs;
+       struct io_u **io_us;
+       unsigned int queued;
+       unsigned long queued_bytes;
+
+       unsigned long long last_offset;
+       struct fio_file *last_file;
+       enum fio_ddir last_ddir;
+};
+
 static int fio_syncio_prep(struct thread_data *td, struct io_u *io_u)
 {
        struct fio_file *f = io_u->file;
@@ -81,6 +92,183 @@ static int fio_syncio_queue(struct thread_data *td, struct io_u *io_u)
        return fio_io_end(td, io_u, ret);
 }
 
+static int fio_vsyncio_getevents(struct thread_data *td, unsigned int min,
+                                unsigned int max,
+                                struct timespec fio_unused *t)
+{
+       struct syncio_data *sd = td->io_ops->data;
+       int ret;
+
+       if (min) {
+               ret = sd->queued;
+               sd->queued = 0;
+       } else
+               ret = 0;
+
+       dprint(FD_IO, "vsyncio_getevents: min=%d,max=%d: %d\n", min, max, ret);
+       return ret;
+}
+
+static struct io_u *fio_vsyncio_event(struct thread_data *td, int event)
+{
+       struct syncio_data *sd = td->io_ops->data;
+
+       return sd->io_us[event];
+}
+
+static int fio_vsyncio_append(struct thread_data *td, struct io_u *io_u)
+{
+       struct syncio_data *sd = td->io_ops->data;
+
+       if (io_u->ddir == DDIR_SYNC)
+               return 0;
+
+       if (io_u->offset == sd->last_offset && io_u->file == sd->last_file &&
+           io_u->ddir == sd->last_ddir)
+               return 1;
+
+       return 0;
+}
+
+static void fio_vsyncio_set_iov(struct syncio_data *sd, struct io_u *io_u,
+                               int index)
+{
+       sd->io_us[index] = io_u;
+       sd->iovecs[index].iov_base = io_u->xfer_buf;
+       sd->iovecs[index].iov_len = io_u->xfer_buflen;
+       sd->last_offset = io_u->offset + io_u->xfer_buflen;
+       sd->last_file = io_u->file;
+       sd->last_ddir = io_u->ddir;
+       sd->queued_bytes += io_u->xfer_buflen;
+       sd->queued++;
+}
+
+static int fio_vsyncio_queue(struct thread_data *td, struct io_u *io_u)
+{
+       struct syncio_data *sd = td->io_ops->data;
+
+       fio_ro_check(td, io_u);
+
+       if (!fio_vsyncio_append(td, io_u)) {
+               dprint(FD_IO, "vsyncio_queue: no append (%d)\n", sd->queued);
+               /*
+                * If we can't append and have stuff queued, tell fio to
+                * commit those first and then retry this io
+                */
+               if (sd->queued)
+                       return FIO_Q_BUSY;
+
+               sd->queued = 0;
+               sd->queued_bytes = 0;
+               fio_vsyncio_set_iov(sd, io_u, 0);
+       } else {
+               if (sd->queued == td->o.iodepth) {
+                       dprint(FD_IO, "vsyncio_queue: max depth %d\n", sd->queued);
+                       return FIO_Q_BUSY;
+               }
+
+               dprint(FD_IO, "vsyncio_queue: append\n");
+               fio_vsyncio_set_iov(sd, io_u, sd->queued);
+       }
+
+       dprint(FD_IO, "vsyncio_queue: depth now %d\n", sd->queued);
+       return FIO_Q_QUEUED;
+}
+
+/*
+ * Check that we transferred all bytes, or saw an error, etc
+ */
+static int fio_vsyncio_end(struct thread_data *td, ssize_t bytes)
+{
+       struct syncio_data *sd = td->io_ops->data;
+       struct io_u *io_u;
+       unsigned int i;
+       int err;
+
+       /*
+        * transferred everything, perfect
+        */
+       if (bytes == sd->queued_bytes)
+               return 0;
+
+       err = errno;
+       for (i = 0; i < sd->queued; i++) {
+               io_u = sd->io_us[i];
+
+               if (bytes == -1) {
+                       io_u->error = err;
+               } else {
+                       unsigned int this_io;
+
+                       this_io = bytes;
+                       if (this_io > io_u->xfer_buflen)
+                               this_io = io_u->xfer_buflen;
+
+                       io_u->resid = io_u->xfer_buflen - this_io;
+                       io_u->error = 0;
+                       bytes -= this_io;
+               }
+       }
+
+       if (bytes == -1) {
+               td_verror(td, err, "xfer vsync");
+               return -err;
+       }
+
+       return 0;
+}
+
+static int fio_vsyncio_commit(struct thread_data *td)
+{
+       struct syncio_data *sd = td->io_ops->data;
+       struct fio_file *f;
+       ssize_t ret;
+
+       if (!sd->queued)
+               return 0;
+
+       f = sd->last_file;
+
+       if (lseek(f->fd, sd->io_us[0]->offset, SEEK_SET) == -1) {
+               int err = -errno;
+
+               td_verror(td, errno, "lseek");
+               return err;
+       }
+
+       if (sd->last_ddir == DDIR_READ)
+               ret = readv(f->fd, sd->iovecs, sd->queued);
+       else
+               ret = writev(f->fd, sd->iovecs, sd->queued);
+
+       dprint(FD_IO, "vsyncio_commit: %d\n", (int) ret);
+       return fio_vsyncio_end(td, ret);
+}
+
+static int fio_vsyncio_init(struct thread_data *td)
+{
+       struct syncio_data *sd;
+
+       sd = malloc(sizeof(*sd));
+       memset(sd, 0, sizeof(*sd));
+       sd->last_offset = -1ULL;
+       sd->iovecs = malloc(td->o.iodepth * sizeof(struct iovec));
+       sd->io_us = malloc(td->o.iodepth * sizeof(struct io_u *));
+
+       td->io_ops->data = sd;
+       return 0;
+}
+
+static void fio_vsyncio_cleanup(struct thread_data *td)
+{
+       struct syncio_data *sd = td->io_ops->data;
+
+       free(sd->iovecs);
+       free(sd->io_us);
+       free(sd);
+       td->io_ops->data = NULL;
+}
+
 static struct ioengine_ops ioengine_rw = {
        .name           = "sync",
        .version        = FIO_IOOPS_VERSION,
@@ -100,14 +288,30 @@ static struct ioengine_ops ioengine_prw = {
        .flags          = FIO_SYNCIO,
 };
 
+static struct ioengine_ops ioengine_vrw = {
+       .name           = "vsync",
+       .version        = FIO_IOOPS_VERSION,
+       .init           = fio_vsyncio_init,
+       .cleanup        = fio_vsyncio_cleanup,
+       .queue          = fio_vsyncio_queue,
+       .commit         = fio_vsyncio_commit,
+       .event          = fio_vsyncio_event,
+       .getevents      = fio_vsyncio_getevents,
+       .open_file      = generic_open_file,
+       .close_file     = generic_close_file,
+       .flags          = FIO_SYNCIO,
+};
+
 static void fio_init fio_syncio_register(void)
 {
        register_ioengine(&ioengine_rw);
        register_ioengine(&ioengine_prw);
+       register_ioengine(&ioengine_vrw);
 }
 
 static void fio_exit fio_syncio_unregister(void)
 {
        unregister_ioengine(&ioengine_rw);
        unregister_ioengine(&ioengine_prw);
+       unregister_ioengine(&ioengine_vrw);
 }

diff --git a/options.c b/options.c
index 3de2ae615fb3d1683625ce42f9b0ad9d7947eb13..1e99810e19e8de94fd51a8562842ae42aff4457e 100644 (file)
--- a/options.c
+++ b/options.c
@@ -440,6 +440,9 @@ static struct fio_option options[] = {
                          { .ival = "psync",
                            .help = "Use pread/pwrite",
                          },
+                         { .ival = "vsync",
+                            .help = "Use readv/writev",
+                         },
 #ifdef FIO_HAVE_LIBAIO
                          { .ival = "libaio",
                            .help = "Linux native asynchronous IO",