Re: [PATCH 3/3] io_uring: Support IOSQE_CQE_SKIP_SUCCESS in io_uring zerocopy test

Muhammad Usama Anjum
2024-04-06T20:32:56Z

On 4/5/24 3:19 AM, Oliver Crumrine wrote:
> Add support for the IOSQE_CQE_SKIP_SUCCESS flag in the io_uring_zerocopy_tx
> test, using the "-a" option. Instead of incrementing when
> IORING_CQE_F_MORE is set, remember how many SQEs are sent and simply
> wait on notifs instead of regular completions. For non-zc stuff, there
> won't be notifs or completions, so don't wait on either of those, but
> check the completion queue for errors at the end to make sure none have
> popped up.
>
> The changes to the shell script run the tests both with and without the
> "-a" option.
>
> Signed-off-by: Oliver Crumrine <ozlinuxc@gmail.com>
Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>

> ---
> .../selftests/net/io_uring_zerocopy_tx.c | 38 +++++++++++++++++--
> .../selftests/net/io_uring_zerocopy_tx.sh | 7 +++-
> 2 files changed, 39 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/net/io_uring_zerocopy_tx.c b/tools/testing/selftests/net/io_uring_zerocopy_tx.c
> index 76e604e4810e..11a43594935f 100644
> --- a/tools/testing/selftests/net/io_uring_zerocopy_tx.c
> +++ b/tools/testing/selftests/net/io_uring_zerocopy_tx.c
> @@ -50,8 +50,10 @@ enum {
> };
>
> static bool cfg_cork = false;
> +static bool cfg_nocqe = false;
> static int cfg_mode = MODE_ZC_FIXED;
> static int cfg_nr_reqs = 8;
> +static int cfg_nr_completions = 8;
> static int cfg_family = PF_UNSPEC;
> static int cfg_payload_len;
> static int cfg_port = 8000;
> @@ -134,11 +136,21 @@ static void do_tx(int domain, int type, int protocol)
> if (mode == MODE_NONZC) {
> io_uring_prep_send(sqe, fd, payload,
> cfg_payload_len, msg_flags);
> + if (cfg_nocqe) {
> + sqe->flags |= IOSQE_CQE_SKIP_SUCCESS;
> + cfg_nr_completions--;
> + }
> sqe->user_data = NONZC_TAG;
> } else {
> io_uring_prep_sendzc(sqe, fd, payload,
> cfg_payload_len,
> msg_flags, zc_flags);
> + if (cfg_nocqe) {
> + sqe->flags |= IOSQE_CQE_SKIP_SUCCESS;
> + packets++;
> + compl_cqes++;
> + bytes += cfg_payload_len;
> + }
> if (mode == MODE_ZC_FIXED) {
> sqe->ioprio |= IORING_RECVSEND_FIXED_BUF;
> sqe->buf_index = buf_idx;
> @@ -153,7 +165,7 @@ static void do_tx(int domain, int type, int protocol)
>
> if (cfg_cork)
> do_setsockopt(fd, IPPROTO_UDP, UDP_CORK, 0);
> - for (i = 0; i < cfg_nr_reqs; i++) {
> + for (i = 0; i < cfg_nr_completions; i++) {
> ret = io_uring_wait_cqe(&ring, &cqe);
> if (ret)
> error(1, ret, "wait cqe");
> @@ -168,7 +180,9 @@ static void do_tx(int domain, int type, int protocol)
> if (compl_cqes <= 0)
> error(1, -EINVAL, "notification mismatch");
> compl_cqes--;
> - i--;
> + if (!cfg_nocqe)
> + i--;
> io_uring_cqe_seen(&ring);
> continue;
> }
> @@ -200,6 +214,17 @@ static void do_tx(int domain, int type, int protocol)
> compl_cqes--;
> }
>
> + /* The above code does not account for a send error when
> + * IOSQE_CQE_SKIP_SUCCESS is set. This is operating under the
> + * assumption that an error CQE will get put on the ring before
> + * the above code completes:
> + */
> + while (!io_uring_peek_cqe(&ring, &cqe)) {
> + if (cqe->res == -EAGAIN)
> + continue;
> + error(1, -EINVAL, "send failed");
> + }
> +
> fprintf(stderr, "tx=%lu (MB=%lu), tx/s=%lu (MB/s=%lu)\n",
> packets, bytes >> 20,
> packets / (cfg_runtime_ms / 1000),
> @@ -221,7 +246,7 @@ static void do_test(int domain, int type, int protocol)
> static void usage(const char *filepath)
> {
> error(1, 0, "Usage: %s (-4|-6) (udp|tcp) -D<dst_ip> [-s<payload size>] "
> - "[-t ] [-n<batch>] [-p<port>] [-m<mode>]", filepath);
> + "[-t ] [-n<batch>] [-p<port>] [-m<mode>] [-a]", filepath);
> }
>
> static void parse_opts(int argc, char **argv)
> @@ -239,7 +264,7 @@ static void parse_opts(int argc, char **argv)
> usage(argv[0]);
> cfg_payload_len = max_payload_len;
>
> - while ((c = getopt(argc, argv, "46D:p:s:t:n:c:m:")) != -1) {
> + while ((c = getopt(argc, argv, "46aD:p:s:t:n:c:m:")) != -1) {
> switch (c) {
> case '4':
> if (cfg_family != PF_UNSPEC)
> @@ -274,6 +299,9 @@ static void parse_opts(int argc, char **argv)
> case 'm':
> cfg_mode = strtol(optarg, NULL, 0);
> break;
> + case 'a':
> + cfg_nocqe = true;
> + break;
> }
> }
>
> @@ -302,6 +330,8 @@ static void parse_opts(int argc, char **argv)
> error(1, 0, "-s: payload exceeds max (%d)", max_payload_len);
> if (optind != argc - 1)
> usage(argv[0]);
> +
> + cfg_nr_completions = cfg_nr_reqs;
> }
>
> int main(int argc, char **argv)
> diff --git a/tools/testing/selftests/net/io_uring_zerocopy_tx.sh b/tools/testing/selftests/net/io_uring_zerocopy_tx.sh
> index 123439545013..aeb4645b7891 100755
> --- a/tools/testing/selftests/net/io_uring_zerocopy_tx.sh
> +++ b/tools/testing/selftests/net/io_uring_zerocopy_tx.sh
> @@ -25,11 +25,14 @@ readonly path_sysctl_mem="net.core.optmem_max"
> # No arguments: automated test
> if [[ "$#" -eq "0" ]]; then
> IPs=( "4" "6" )
> + SKIPCQEs=("" "-a")
>
> for IP in "${IPs[@]}"; do
> for mode in $(seq 1 3); do
> - $0 "$IP" udp -m "$mode" -t 1 -n 32
> - $0 "$IP" tcp -m "$mode" -t 1 -n 1
> + for cqe in "${SKIPCQEs[@]}"; do
> + $0 "$IP" udp -m "$mode" -t 1 -n 32 "$cqe"
> + $0 "$IP" tcp -m "$mode" -t 1 -n 1 "$cqe"
> + done
> done
> done
>

--
BR,
Muhammad Usama Anjum