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Wythe" , Dust Li , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Tony Lu , Wen Gu , netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, Halil Pasic Subject: Re: [PATCH net-next v3 1/2] net/smc: make wr buffer count configurable Message-ID: <20250925132540.74091295.pasic@linux.ibm.com> In-Reply-To: <7cc2df09-0230-40cb-ad4f-656b0d1d785b@redhat.com> References: <20250921214440.325325-1-pasic@linux.ibm.com> <20250921214440.325325-2-pasic@linux.ibm.com> <7cc2df09-0230-40cb-ad4f-656b0d1d785b@redhat.com> Organization: IBM X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=L50dQ/T8 c=1 sm=1 tr=0 ts=68d526bc cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=kj9zAlcOel0A:10 a=yJojWOMRYYMA:10 a=20KFwNOVAAAA:8 a=AX5NG-fjE0sAVBkmVVgA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTIwMDAxMCBTYWx0ZWRfXwmH4BqZNWINJ 66oCEAr2m76HVkEnVPnJWaz9VlMxVqrVN6G+tUv5A7M8MUI8Vcz0c9k+0paqLeNEWbrfp/fSh6Y Z0MpqPdwMQczFRUoIPUkhTyWShCYNZRfrcEN9b2X/Yv2gWb62huM0CWcUUYHJk11VQpE9XiYvnm KTxZjlNPGC59ImKnonHqDG8iIM7eZM+9zOULHBk/ONGJWTcUFNbbfvP/uZ4idX1s0r4tnOXFk1K tywD+q8ovOX3UWlWf+iFNpadckqlgce4qNvU7Q1+EF2Nv13db19uHc6WzrKMToaATaIXlbv4kHQ k6DMjmCV97voM8u+eUD5AfAm+LKHdZ5TNIaF8k9GN9qWBymQt8V63NTcbi95cAQZMKynjNWj+lq emP4airN X-Proofpoint-ORIG-GUID: HWXWXpRVgwWqwqZ-BPbuPsqi-76RIJrY X-Proofpoint-GUID: cS1p2UpoI1fDrNznIt1dB83-s_-ZOBWg X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-24_07,2025-09-24_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 adultscore=0 phishscore=0 impostorscore=0 spamscore=0 priorityscore=1501 suspectscore=0 clxscore=1015 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2509200010 On Thu, 25 Sep 2025 11:27:38 +0200 Paolo Abeni wrote: [..] > > +smcr_max_recv_wr - INTEGER > > + So called work request buffers are SMCR link (and RDMA queue pair) level > > + resources necessary for performing RDMA operations. Since up to 255 > > + connections can share a link group and thus also a link and the number > > + of the work request buffers is decided when the link is allocated, > > + depending on the workload it can a bottleneck in a sense that threads > > same here^^ Sorry about those! Will fix for v4. > > [...] > > @@ -683,6 +678,8 @@ int smc_ib_create_queue_pair(struct smc_link *lnk) > > }; > > int rc; > > > > + qp_attr.cap.max_send_wr = 3 * lnk->lgr->max_send_wr; > > + qp_attr.cap.max_recv_wr = lnk->lgr->max_recv_wr; > > Possibly: > > cap = max(3 * lnk->lgr->max_send_wr, lnk->lgr->max_recv_wr); > qp_attr.cap.max_send_wr = cap; > qp_attr.cap.max_recv_wr = cap > > to avoid assumption on `max_send_wr`, `max_recv_wr` relative values. Can you explain a little more. I'm happy to do the change, but I would prefer to understand why is keeping qp_attr.cap.max_send_wr == qp_attr.cap.max_recv_wr better? But if you tell: "Just trust me!" I will. [..] > > > > diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c > > index b04a21b8c511..f5b2772414fd 100644 > > --- a/net/smc/smc_wr.c > > +++ b/net/smc/smc_wr.c > > @@ -34,6 +34,7 @@ > > #define SMC_WR_MAX_POLL_CQE 10 /* max. # of compl. queue elements in 1 poll */ > > > > #define SMC_WR_RX_HASH_BITS 4 > > + > > Please avoid unrelated whitespace only changes. Will fix for v4. Really sorry! Regards, Halil