On Fri, Sep 04 2009, Chris Worley wrote:
> Are there example uses, specifically for mixed read/write cases?
>
> I've found I can do sequential writes followed by sequential reads w/o
> issue, but have errors in other cases.
>
> Just some usage hints would be nice.
I think the major issue here is that fio can be used to verify a
previously written file, so it'll attach a verify handler to the IO
piece even for the reads in a mixed workload. Not sure how best to
handle that, the below patch will disable that 'feature' if we are doing
a mixed read/write workload. Which probably does make sense, since it's
fairly nonsensical to expect partial read verifies from a previous file
while overwriting other parts of it...
Does it work?
diff --git a/fio.c b/fio.c
index dfd15e0..3a9a3ba 100644
--- a/fio.c
+++ b/fio.c
@@ -606,7 +606,8 @@ static void do_io(struct thread_data *td)
* Add verification end_io handler, if asked to verify
* a previously written file.
*/
- if (td->o.verify != VERIFY_NONE && io_u->ddir == DDIR_READ) {
+ if (td->o.verify != VERIFY_NONE && io_u->ddir == DDIR_READ &&
+ !td_rw(td)) {
if (td->o.verify_async)
io_u->end_io = verify_io_u_async;
else
--
Jens Axboe
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