why set recv_sge_list start addr refer to buf start addr after post the recv wqes of tx-depth

[smiceice]

file: perftest/src /perftest_resources.c

int ctx_set_recv_wqes(struct pingpong_context *ctx,struct perftest_parameters *user_param)
{
int i = 0,j,k;
int num_of_qps = user_param->num_of_qps;
struct ibv_recv_wr *bad_wr_recv;
int size_per_qp = user_param->rx_depth / user_param->recv_post_list;

if((user_param->use_xrc || user_param->connection_type == DC) &&
			(user_param->duplex || user_param->tst == LAT)) {

	i = user_param->num_of_qps / 2;
	num_of_qps /= 2;
}

if (user_param->use_srq)
	size_per_qp /= user_param->num_of_qps;
ctx->rposted = size_per_qp * user_param->recv_post_list;

for (k = 0; i < user_param->num_of_qps; i++,k++) {
	if (!user_param->mr_per_qp) {
		ctx->recv_sge_list[i * user_param->recv_post_list].addr = (uintptr_t)ctx->buf[0] +
			(num_of_qps + k) * ctx->send_qp_buff_size;
	} else {
		ctx->recv_sge_list[i * user_param->recv_post_list].addr = (uintptr_t)ctx->buf[i];
	}

	if (user_param->connection_type == UD)
		ctx->recv_sge_list[i * user_param->recv_post_list].addr += (ctx->cache_line_size - UD_ADDITION);

	ctx->rx_buffer_addr[i] = ctx->recv_sge_list[i * user_param->recv_post_list].addr;

	for (j = 0; j < user_param->recv_post_list; j++) {
		ctx->recv_sge_list[i * user_param->recv_post_list + j].length = SIZE(user_param->connection_type,user_param->size,1);
		ctx->recv_sge_list[i * user_param->recv_post_list + j].lkey   = ctx->mr[i]->lkey;

		if (j > 0) {
			ctx->recv_sge_list[i * user_param->recv_post_list + j].addr = ctx->recv_sge_list[i * user_param->recv_post_list + j - 1].addr;

			if ((user_param->tst == BW || user_param->tst == LAT_BY_BW) && user_param->size <= (ctx->cycle_buffer / 2)) {
				increase_loc_addr(&ctx->recv_sge_list[i * user_param->recv_post_list + j],
						user_param->size,
						j,
						ctx->rx_buffer_addr[i],
						user_param->connection_type,ctx->cache_line_size,ctx->cycle_buffer);
			}
		}

		ctx->rwr[i * user_param->recv_post_list + j].sg_list = &ctx->recv_sge_list[i * user_param->recv_post_list + j];
		ctx->rwr[i * user_param->recv_post_list + j].num_sge = MAX_RECV_SGE;
		ctx->rwr[i * user_param->recv_post_list + j].wr_id   = i;

		if (j == (user_param->recv_post_list - 1))
			ctx->rwr[i * user_param->recv_post_list + j].next = NULL;
		else
			ctx->rwr[i * user_param->recv_post_list + j].next = &ctx->rwr[i * user_param->recv_post_list + j + 1];
	}

	for (j = 0; j < size_per_qp ; ++j) {

		if (user_param->use_srq) {

			if (ibv_post_srq_recv(ctx->srq,&ctx->rwr[i * user_param->recv_post_list], &bad_wr_recv)) {
				fprintf(stderr, "Couldn't post recv SRQ = %d: counter=%d\n",i,j);
				return 1;
			}

		} else {

			if (ibv_post_recv(ctx->qp[i],&ctx->rwr[i * user_param->recv_post_list],&bad_wr_recv)) {
				fprintf(stderr, "Couldn't post recv Qp = %d: counter=%d\n",i,j);
				return 1;
			}
		}

		if (user_param->recv_post_list == 1 && (user_param->tst == BW || user_param->tst == LAT_BY_BW) &&
				user_param->size <= (ctx->cycle_buffer / 2)) {
			increase_loc_addr(&ctx->recv_sge_list[i * user_param->recv_post_list],
					user_param->size,
					j,
					ctx->rx_buffer_addr[i],
					user_param->connection_type,ctx->cache_line_size,ctx->cycle_buffer);
		}
	}
	**ctx->recv_sge_list[i * user_param->recv_post_list].addr = ctx->rx_buffer_addr[i];**
}
return 0;

}

because of that line, there will has the same number of wqes as rx-depth use the same buf addr and data will be overwritten

I don't know whether my understanding is correct or not, and whether there are other dependent uses in this line?

[sshaulnv]

Hi @smice-ICE,
thanks for you contribution.
can you mark the line you meant and explain your question more briefly please?

also, we are not preforming validation to the message.

[smiceice]

the line is " ctx->recv_sge_list[i * user_param->recv_post_list].addr = ctx->rx_buffer_addr[i];"

in send/recv mode
at first, server side will post tx-depth recv wqes, those wqes addr is start at buf[i]+offset
after then, new rwqes addr is still start at buf[i]+offset
so the first tx-depth wqes and the second tx-depth wqes will use same addr