On Tue, May 20, 2025 at 1:30 PM Stanislav Fomichev <stfomic...@gmail.com> wrote:
>
> Add new -z argument to specify max IOV size. By default, use
> single large IOV.
>
> Signed-off-by: Stanislav Fomichev <stfomic...@gmail.com>
> ---
> .../selftests/drivers/net/hw/ncdevmem.c | 49 +++++++++++--------
> 1 file changed, 29 insertions(+), 20 deletions(-)
>
> diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> index ca723722a810..fc7ba7d71502 100644
> --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
> @@ -82,6 +82,9 @@
> #define MSG_SOCK_DEVMEM 0x2000000
> #endif
>
> +#define MAX_IOV 1024
> +
> +static size_t max_chunk;
> static char *server_ip;
> static char *client_ip;
> static char *port;
> @@ -834,10 +837,10 @@ static int do_client(struct memory_buffer *mem)
> struct sockaddr_in6 server_sin;
> struct sockaddr_in6 client_sin;
> struct ynl_sock *ys = NULL;
> + struct iovec iov[MAX_IOV];
> struct msghdr msg = {};
> ssize_t line_size = 0;
> struct cmsghdr *cmsg;
> - struct iovec iov[2];
> char *line = NULL;
> unsigned long mid;
> size_t len = 0;
> @@ -893,27 +896,29 @@ static int do_client(struct memory_buffer *mem)
> if (line_size < 0)
> break;
>
> - mid = (line_size / 2) + 1;
> -
> - iov[0].iov_base = (void *)1;
> - iov[0].iov_len = mid;
> - iov[1].iov_base = (void *)(mid + 2);
> - iov[1].iov_len = line_size - mid;
> + if (max_chunk) {
> + msg.msg_iovlen =
> + (line_size + max_chunk - 1) / max_chunk;
> + if (msg.msg_iovlen > MAX_IOV)
> + error(1, 0,
> + "can't partition %zd bytes into maximum
> of %d chunks",
> + line_size, MAX_IOV);
>
> - provider->memcpy_to_device(mem, (size_t)iov[0].iov_base, line,
> - iov[0].iov_len);
> - provider->memcpy_to_device(mem, (size_t)iov[1].iov_base,
> - line + iov[0].iov_len,
> - iov[1].iov_len);
> + for (int i = 0; i < msg.msg_iovlen; i++) {
> + iov[i].iov_base = (void *)(i * max_chunk);
> + iov[i].iov_len = max_chunk;
Isn't the last iov going to be truncated in the case where line_size
is not exactly divisible with max_chunk?
> + }
>
> - fprintf(stderr,
> - "read line_size=%ld iov[0].iov_base=%lu,
> iov[0].iov_len=%lu, iov[1].iov_base=%lu, iov[1].iov_len=%lu\n",
> - line_size, (unsigned long)iov[0].iov_base,
> - iov[0].iov_len, (unsigned long)iov[1].iov_base,
> - iov[1].iov_len);
> + iov[msg.msg_iovlen - 1].iov_len =
> + line_size - (msg.msg_iovlen - 1) * max_chunk;
> + } else {
> + iov[0].iov_base = 0;
> + iov[0].iov_len = line_size;
> + msg.msg_iovlen = 1;
> + }
Do you need to special case this? Shouldn't this be the same as max_chunk==1?
>
> msg.msg_iov = iov;
> - msg.msg_iovlen = 2;
> + provider->memcpy_to_device(mem, 0, line, line_size);
>
> msg.msg_control = ctrl_data;
> msg.msg_controllen = sizeof(ctrl_data);
> @@ -934,7 +939,8 @@ static int do_client(struct memory_buffer *mem)
> fprintf(stderr, "sendmsg_ret=%d\n", ret);
>
> if (ret != line_size)
> - error(1, errno, "Did not send all bytes");
> + error(1, errno, "Did not send all bytes %d vs %zd",
> ret,
> + line_size);
>
> wait_compl(socket_fd);
> }
> @@ -956,7 +962,7 @@ int main(int argc, char *argv[])
> int is_server = 0, opt;
> int ret;
>
> - while ((opt = getopt(argc, argv, "ls:c:p:v:q:t:f:")) != -1) {
> + while ((opt = getopt(argc, argv, "ls:c:p:v:q:t:f:z:")) != -1) {
> switch (opt) {
> case 'l':
> is_server = 1;
> @@ -982,6 +988,9 @@ int main(int argc, char *argv[])
> case 'f':
> ifname = optarg;
> break;
> + case 'z':
> + max_chunk = atoi(optarg);
> + break;
> case '?':
> fprintf(stderr, "unknown option: %c\n", optopt);
> break;
> --
> 2.49.0
>
--
Thanks,
Mina
