From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Sat, 15 Oct 2022 19:41:08 +0000 (+0300)
Subject: fio: warn about "ioengine=psync" and "iodepth >= 1"
X-Git-Tag: fio-3.33~16
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=349d5f6c30cc7be60da8878d0b0078697f356897;p=fio.git

fio: warn about "ioengine=psync" and "iodepth >= 1"

Some users are using both ioengine=psync and iodepth=2+
without blinking in front of the millions:

	https://youtu.be/coShLkCriXc?t=840
	https://youtu.be/coShLkCriXc?t=890

Help them with helpful message.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/Y0sM1PJKEzfv47ZB@localhost.localdomain
[axboe: style fixup]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/backend.c b/backend.c
index ec535bcc..d8f4f2a5 100644
--- a/backend.c
+++ b/backend.c
@@ -1791,6 +1791,11 @@ static void *thread_main(void *data)
 	if (td_io_init(td))
 		goto err;
 
+	if (td_ioengine_flagged(td, FIO_SYNCIO) && td->o.iodepth > 1) {
+		log_info("note: both iodepth >= 1 and synchronous I/O engine "
+			 "are selected, queue depth will be capped at 1\n");
+	}
+
 	if (init_io_u(td))
 		goto err;