diff mbox

[V9fs-developer,04/10] 9P/RDMA: increase P9_RDMA_MAXSIZE to 1MB

Message ID 1371821563-5784-5-git-send-email-simon.derr@bull.net (mailing list archive)
State New, archived
Headers show

Commit Message

Simon Derr June 21, 2013, 1:32 p.m. UTC
The current value is too low to get good performance.

Signed-off-by: Simon Derr <simon.derr@bull.net>
---
 net/9p/trans_rdma.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

Comments

Dominique Martinet July 3, 2013, 8:01 a.m. UTC | #1
Hi,

Simon Derr wrote on Fri, Jun 21, 2013 :
> -#define P9_RDMA_MAXSIZE		(4*4096)	/* Min SGE is 4, so we can
> -						 * safely advertise a maxsize
> -						 * of 64k */
> +#define P9_RDMA_MAXSIZE		(1024*1024)	/* 1MB */

May I push my luck and suggest we use 1024*1024 + 24?

The idea would be to be able to do read and write requests of exactly
1MB, which need the extra bit because write has a 23 bytes overhead
(read only has 11) - but it will also need the vfs calls to ask for the
exact size that will no longer be obvious from the msize
I guess that as long as we don't have this it would be negative to bring
this further up - comments welcome before I look into it.


That being said, we've been running many tests here with all these
patches for a while and there doesn't seem to be any problem.


Regards,
diff mbox

Patch

diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index b1dfdf2..b8b66d3 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -57,9 +57,7 @@ 
 #define P9_RDMA_IRD		0
 #define P9_RDMA_ORD		0
 #define P9_RDMA_TIMEOUT		30000		/* 30 seconds */
-#define P9_RDMA_MAXSIZE		(4*4096)	/* Min SGE is 4, so we can
-						 * safely advertise a maxsize
-						 * of 64k */
+#define P9_RDMA_MAXSIZE		(1024*1024)	/* 1MB */
 
 /**
  * struct p9_trans_rdma - RDMA transport instance