Re: [PATCH net-next v3 1/2] net/smc: make wr buffer count configurable
From: Halil Pasic <pasic@linux.ibm.com>
Date: 2025-09-27 22:55:32
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On Thu, 25 Sep 2025 13:25:40 +0200 Halil Pasic [off-list ref] wrote:
quoted
[...]quoted
@@ -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.
Due to a little accident we ended up having a private conversation on this, which I'm going to sum up quickly. Paolo stated that he has no strong preference and that I should at least add a comment, which I will do for v4. Unfortunately I don't quite understand why qp_attr.cap.max_send_wr is 3 times the number of send WR buffers we allocate. My understanding is that qp_attr.cap.max_send_wr is about the number of send WQEs. I assume that qp_attr.cap.max_send_wr == qp_attr.cap.max_recv_wr is not something we would want to preserve. Regards, Halil