The following changes since commit 79baf7f48a6e680e1e746e150b60c165542fdf6c:
Fio 2.13 (2016-07-22 13:43:56 -0600)
are available in the git repository at:
git://git.kernel.dk/fio.git master
for you to fetch changes up to fa3cdbb7a46e42186e8fa62d33b82b92c7c0e310:
Add sample job file showing how to read backwards (2016-07-26 14:50:02 -0600)
----------------------------------------------------------------
Jens Axboe (2):
Revert "Revert "fio: Simplify forking of processes""
Add sample job file showing how to read backwards
backend.c | 46 +++++++--------------------------------------
examples/backwards-read.fio | 7 +++++++
2 files changed, 14 insertions(+), 39 deletions(-)
create mode 100644 examples/backwards-read.fio
---
Diff of recent changes:
diff --git a/backend.c b/backend.c
index 58c77cb..ad2d7da 100644
--- a/backend.c
+++ b/backend.c
@@ -1808,39 +1808,6 @@ err:
return (void *) (uintptr_t) td->error;
}
-
-/*
- * We cannot pass the td data into a forked process, so attach the td and
- * pass it to the thread worker.
- */
-static int fork_main(struct sk_out *sk_out, int shmid, int offset)
-{
- struct fork_data *fd;
- void *data, *ret;
-
-#if !defined(__hpux) && !defined(CONFIG_NO_SHM)
- data = shmat(shmid, NULL, 0);
- if (data == (void *) -1) {
- int __err = errno;
-
- perror("shmat");
- return __err;
- }
-#else
- /*
- * HP-UX inherits shm mappings?
- */
- data = threads;
-#endif
-
- fd = calloc(1, sizeof(*fd));
- fd->td = data + offset * sizeof(struct thread_data);
- fd->sk_out = sk_out;
- ret = thread_main(fd);
- shmdt(data);
- return (int) (uintptr_t) ret;
-}
-
static void dump_td_info(struct thread_data *td)
{
log_err("fio: job '%s' (state=%d) hasn't exited in %lu seconds, it "
@@ -2178,6 +2145,7 @@ reap:
struct thread_data *map[REAL_MAX_JOBS];
struct timeval this_start;
int this_jobs = 0, left;
+ struct fork_data *fd;
/*
* create threads (TD_NOT_CREATED -> TD_CREATED)
@@ -2227,14 +2195,13 @@ reap:
map[this_jobs++] = td;
nr_started++;
+ fd = calloc(1, sizeof(*fd));
+ fd->td = td;
+ fd->sk_out = sk_out;
+
if (td->o.use_thread) {
- struct fork_data *fd;
int ret;
- fd = calloc(1, sizeof(*fd));
- fd->td = td;
- fd->sk_out = sk_out;
-
dprint(FD_PROCESS, "will pthread_create\n");
ret = pthread_create(&td->thread, NULL,
thread_main, fd);
@@ -2254,8 +2221,9 @@ reap:
dprint(FD_PROCESS, "will fork\n");
pid = fork();
if (!pid) {
- int ret = fork_main(sk_out, shm_id, i);
+ int ret;
+ ret = (int)(uintptr_t)thread_main(fd);
_exit(ret);
} else if (i == fio_debug_jobno)
*fio_debug_jobp = pid;
diff --git a/examples/backwards-read.fio b/examples/backwards-read.fio
new file mode 100644
index 0000000..ddd47e4
--- /dev/null
+++ b/examples/backwards-read.fio
@@ -0,0 +1,7 @@
+# Demonstrates how to read backwards in a file.
+
+[backwards-read]
+bs=4k
+# seek -8k back for every IO
+rw=read:-8k
+filename=128m
--
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