Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:28364 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932500AbbGJOd0 convert rfc822-to-8bit (ORCPT ); Fri, 10 Jul 2015 10:33:26 -0400 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: [PATCH v1 03/12] xprtrdma: Increase default credit limit From: Chuck Lever In-Reply-To: Date: Fri, 10 Jul 2015 10:33:22 -0400 Cc: linux-rdma@vger.kernel.org, Linux NFS Mailing List Message-Id: References: <20150709203242.26247.4848.stgit@manet.1015granger.net> <20150709204208.26247.52073.stgit@manet.1015granger.net> To: Devesh Sharma Sender: linux-nfs-owner@vger.kernel.org List-ID: On Jul 10, 2015, at 6:45 AM, Devesh Sharma wrote: > Increasing the default slot table entries will increase the MR > requirements per mount. Yes, but: > Currently, with 32 as default Client ends up allocating 2178 frmrs > (ref: kernel 4.1-rc4) for a single mount. With 128 frmr requirement > for startup would be 8448. Commit 40c6ed0c8a7f ("xprtrdma: Reduce per-transport MR allocation?) is supposed to address this. This commit is in 4.1. The number of MRs per credit is now 256 divided by the HCA?s max_fast_reg_page_list_len. See frwr_op_open(). For mlx4 the number of MRs per credit is just 1, for example. > 8K+ MRs per mount just for start-up, I am a little doubtful about this > change. We can always release-note that "for better performance > increase the slot table entries by echo 128 > > /proc/sys/sunrpc/rdma_slot_table_entries" > > -Regards > Devesh > > On Fri, Jul 10, 2015 at 2:12 AM, Chuck Lever wrote: >> In preparation for similar increases on NFS/RDMA servers, bump the >> advertised credit limit for RPC/RDMA to 128. This allocates some >> extra resources, but the client will continue to allow only the >> number of RPCs in flight that the server requests via its advertised >> credit limit. >> >> Signed-off-by: Chuck Lever >> --- >> include/linux/sunrpc/xprtrdma.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/sunrpc/xprtrdma.h b/include/linux/sunrpc/xprtrdma.h >> index b176130..b7b279b 100644 >> --- a/include/linux/sunrpc/xprtrdma.h >> +++ b/include/linux/sunrpc/xprtrdma.h >> @@ -49,7 +49,7 @@ >> * a single chunk type per message is supported currently. >> */ >> #define RPCRDMA_MIN_SLOT_TABLE (2U) >> -#define RPCRDMA_DEF_SLOT_TABLE (32U) >> +#define RPCRDMA_DEF_SLOT_TABLE (128U) >> #define RPCRDMA_MAX_SLOT_TABLE (256U) >> >> #define RPCRDMA_DEF_INLINE (1024) /* default inline max */ >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever