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From: Chuck Lever <chuck.lever@oracle.com>
To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org
Subject: [PATCH v1 18/18] xprtrdma: Optimize rpcrdma_post_recvs()
Date: Tue, 06 Aug 2019 11:55:22 -0400
Message-ID: <20190806155521.9529.80398.stgit@manet.1015granger.net> (raw)
In-Reply-To: <20190806155246.9529.14571.stgit@manet.1015granger.net>

Micro-optimization: In rpcrdma_post_recvs, since commit e340c2d6ef2a
("xprtrdma: Reduce the doorbell rate (Receive)"), the common case is
to return without doing anything. Found with perf.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/verbs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 4112b8a..36e840b 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1457,7 +1457,7 @@ static void rpcrdma_regbuf_free(struct rpcrdma_regbuf *rb)
 	count = 0;
 
 	needed = buf->rb_credits + (buf->rb_bc_srv_max_requests << 1);
-	if (ep->rep_receive_count > needed)
+	if (likely(ep->rep_receive_count > needed))
 		goto out;
 	needed -= ep->rep_receive_count;
 	if (!temp)


      parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-06 15:53 [PATCH v1 00/18] NFS/RDMA patches Chuck Lever
2019-08-06 15:53 ` [PATCH v1 01/18] xprtrdma: Refresh the documenting comment in frwr_ops.c Chuck Lever
2019-08-06 15:53 ` [PATCH v1 02/18] xprtrdma: Fix calculation of ri_max_segs again Chuck Lever
2019-08-06 15:54 ` [PATCH v1 03/18] xprtrdma: Boost maximum transport header size Chuck Lever
2019-08-06 15:54 ` [PATCH v1 04/18] xprtrdma: Boost client's max slot table size to match Linux server Chuck Lever
2019-08-06 15:54 ` [PATCH v1 05/18] xprtrdma: Rename CQE field in Receive trace points Chuck Lever
2019-08-06 15:54 ` [PATCH v1 06/18] xprtrdma: Rename rpcrdma_buffer::rb_all Chuck Lever
2019-08-06 15:54 ` [PATCH v1 07/18] xprtrdma: Toggle XPRT_CONGESTED in xprtrdma's slot methods Chuck Lever
2019-08-06 15:54 ` [PATCH v1 08/18] xprtrdma: Simplify rpcrdma_mr_pop Chuck Lever
2019-08-06 15:54 ` [PATCH v1 09/18] xprtrdma: Combine rpcrdma_mr_put and rpcrdma_mr_unmap_and_put Chuck Lever
2019-08-06 15:54 ` [PATCH v1 10/18] xprtrdma: Move rpcrdma_mr_get out of frwr_map Chuck Lever
2019-08-06 15:54 ` [PATCH v1 11/18] xprtrdma: Ensure creating an MR does not trigger FS writeback Chuck Lever
2019-08-06 15:54 ` [PATCH v1 12/18] xprtrdma: Cache free MRs in each rpcrdma_req Chuck Lever
2019-08-06 15:54 ` [PATCH v1 13/18] xprtrdma: Remove rpcrdma_buffer::rb_mrlock Chuck Lever
2019-08-06 15:55 ` [PATCH v1 14/18] xprtrdma: Use an llist to manage free rpcrdma_reps Chuck Lever
2019-08-06 15:55 ` [PATCH v1 15/18] xprtrdma: Clean up xprt_rdma_set_connect_timeout() Chuck Lever
2019-08-06 15:55 ` [PATCH v1 16/18] xprtdma: Fix bc_max_slots return value Chuck Lever
2019-08-06 15:55 ` [PATCH v1 17/18] xprtrdma: Inline XDR chunk encoder functions Chuck Lever
2019-08-06 15:55 ` Chuck Lever [this message]

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