Add the file sharing bits
authorJens Axboe <jens.axboe@oracle.com>
Sat, 1 Mar 2008 18:25:20 +0000 (19:25 +0100)
committerJens Axboe <jens.axboe@oracle.com>
Sat, 1 Mar 2008 18:25:20 +0000 (19:25 +0100)
When you use the same filename for several jobs now, they will share
the same file structure. Enable locking through two new options:

- lockfile. If set, a semaphore is associated with the file and it is
  held from ->prep() to ->queue() has done its work.
- lockfile_batch. This controls how many IOs the job gets to do per
  semaphore acqusition.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
HOWTO
filesetup.c
fio.h
ioengines.c
options.c

diff --git a/HOWTO b/HOWTO
index d8c6b94..3e0a31b 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -219,6 +219,14 @@ filename=str       Fio normally makes up a filename based on the job name,
 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.
 
+lockfile=bool  If set, fio will lock a file internally before doing IO to it.
+               This makes it safe to share file descriptors across fio
+               jobs that run at the same time.
+
+lockfile_batch=int     Acquiring a semaphore can be quite expensive, so
+               allow a process to complete this number of IOs before releasing
+               the semaphore again. Defaults to 1.
+
 readwrite=str
 rw=str         Type of io pattern. Accepted values are:
 
index e2c71cd..4e2a36c 100644 (file)
@@ -228,8 +228,10 @@ int generic_close_file(struct thread_data fio_unused *td, struct fio_file *f)
 
 int generic_open_file(struct thread_data *td, struct fio_file *f)
 {
+       struct fio_file *__f;
        int is_std = 0;
        int flags = 0;
+       int from_hash = 0;
 
        dprint(FD_FILE, "fd open %s\n", f->file_name);
 
@@ -265,8 +267,16 @@ open_again:
 
                if (is_std)
                        f->fd = dup(STDOUT_FILENO);
-               else
-                       f->fd = open(f->file_name, flags, 0600);
+               else {
+                       __f = lookup_file_hash(f->file_name);
+                       if (__f) {
+                               f->sem = __f->sem;
+                               f->fd = dup(__f->fd);
+                               f->references++;
+                               from_hash = 1;
+                       } else
+                               f->fd = open(f->file_name, flags, 0600);
+               }
        } else {
                if (f->filetype == FIO_TYPE_CHAR && !read_only)
                        flags |= O_RDWR;
@@ -275,8 +285,16 @@ open_again:
 
                if (is_std)
                        f->fd = dup(STDIN_FILENO);
-               else
-                       f->fd = open(f->file_name, flags);
+               else {
+                       __f = lookup_file_hash(f->file_name);
+                       if (__f) {
+                               f->sem = __f->sem;
+                               f->fd = dup(__f->fd);
+                               f->references++;
+                               from_hash = 1;
+                       } else
+                               f->fd = open(f->file_name, flags);
+               }
        }
 
        if (f->fd == -1) {
@@ -296,7 +314,17 @@ open_again:
        if (get_file_size(td, f))
                goto err;
 
-       add_file_hash(f);
+       if (!from_hash && f->fd != -1) {
+               if (add_file_hash(f)) {
+                       int ret;
+
+                       /*
+                        * OK to ignore, we haven't done anything with it
+                        */
+                       ret = generic_close_file(td, f);
+                       goto open_again;
+               }
+       }
 
        return 0;
 err:
@@ -613,6 +641,9 @@ int add_file(struct thread_data *td, const char *fname)
 
        get_file_type(f);
 
+       if (td->o.lockfile)
+               f->sem = fio_sem_init(1);
+
        td->files_index++;
        if (f->filetype == FIO_TYPE_FILE)
                td->nr_normal_files++;
@@ -653,10 +684,29 @@ int put_file(struct thread_data *td, struct fio_file *f)
 
 void lock_file(struct thread_data *td, struct fio_file *f)
 {
+       if (f && f->sem) {
+               if (f->sem_owner == td && f->sem_batch--)
+                       return;
+
+               fio_sem_down(f->sem);
+               f->sem_owner = td;
+               f->sem_batch = td->o.lockfile_batch;
+       }
 }
 
 void unlock_file(struct fio_file *f)
 {
+       if (f && f->sem) {
+               int sem_val;
+
+               if (f->sem_batch)
+                       return;
+
+               sem_getvalue(&f->sem->sem, &sem_val);
+               if (!sem_val)
+                       f->sem_owner = NULL;
+               fio_sem_up(f->sem);
+       }
 }
 
 static int recurse_dir(struct thread_data *td, const char *dirname)
diff --git a/fio.h b/fio.h
index fe1a227..ffd3d7d 100644 (file)
--- a/fio.h
+++ b/fio.h
@@ -22,6 +22,7 @@
 #include "arch/arch.h"
 #include "os/os.h"
 #include "mutex.h"
+#include "sem.h"
 #include "log.h"
 #include "debug.h"
 
@@ -309,6 +310,13 @@ struct fio_file {
 
        unsigned long long last_pos;
 
+       /*
+        * if io is protected by a semaphore, this is set
+        */
+       struct fio_sem *sem;
+       void *sem_owner;
+       unsigned int sem_batch;
+
        /*
         * block map for random io
         */
@@ -407,6 +415,8 @@ struct thread_options {
 
        unsigned int nr_files;
        unsigned int open_files;
+       unsigned int lockfile;
+       unsigned int lockfile_batch;
 
        unsigned int odirect;
        unsigned int invalidate_cache;
index 5a2d6b9..bd2eb4a 100644 (file)
@@ -359,5 +359,10 @@ int td_io_close_file(struct thread_data *td, struct fio_file *f)
         */
        f->flags |= FIO_FILE_CLOSING;
 
+       if (f->sem_owner == td && f->sem_batch) {
+               f->sem_batch = 0;
+               unlock_file(f);
+       }
+
        return put_file(td, f);
 }
index 1119a98..27b4fb6 100644 (file)
--- a/options.c
+++ b/options.c
@@ -384,6 +384,22 @@ static struct fio_option options[] = {
                .cb     = str_filename_cb,
                .help   = "File(s) to use for the workload",
        },
+       {
+               .name   = "lockfile",
+               .type   = FIO_OPT_BOOL,
+               .off1   = td_var_offset(lockfile),
+               .help   = "Lock file when doing IO to it",
+               .parent = "filename",
+               .def    = "0",
+       },
+       {
+               .name   = "lockfile_batch",
+               .type   = FIO_OPT_INT,
+               .off1   = td_var_offset(lockfile_batch),
+               .help   = "Number of IOs to allow per file lock",
+               .parent = "lockfile",
+               .def    = "1",
+       },
        {
                .name   = "opendir",
                .type   = FIO_OPT_STR_STORE,