diff options
| author | Willem de Bruijn <willemb@google.com> | 2023-07-31 14:08:09 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-08-02 11:40:49 +0100 |
| commit | bd60438eeb1ebe9415b157398083b4910c7f0aa3 (patch) | |
| tree | c86b1a8c3aff424cd4acc3b07a1e01b5c54c73fe | |
| parent | 27bcd12295164c710369a94e56dc1ddfee1bbb75 (diff) | |
| download | linux-bd60438eeb1ebe9415b157398083b4910c7f0aa3.tar.gz linux-bd60438eeb1ebe9415b157398083b4910c7f0aa3.tar.bz2 linux-bd60438eeb1ebe9415b157398083b4910c7f0aa3.zip | |
selftests/net: report rcv_mss in tcp_mmap
tcp_mmap tests TCP_ZEROCOPY_RECEIVE. If 0% of data is received using
mmap, this may be due to mss. Report rcv_mss to identify this cause.
Output of a run failed due to too small mss:
received 32768 MB (0 % mmap'ed) in 8.40458 s, 32.7057 Gbit
cpu usage user:0.027922 sys:8.21126, 251.44 usec per MB, 3252 c-switches, rcv_mss 1428
Output on a successful run:
received 32768 MB (99.9507 % mmap'ed) in 4.69023 s, 58.6064 Gbit
cpu usage user:0.029172 sys:2.56105, 79.0473 usec per MB, 57591 c-switches, rcv_mss 4096
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | tools/testing/selftests/net/tcp_mmap.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/tools/testing/selftests/net/tcp_mmap.c b/tools/testing/selftests/net/tcp_mmap.c index 6e59b1461dcc..4fcce5150850 100644 --- a/tools/testing/selftests/net/tcp_mmap.c +++ b/tools/testing/selftests/net/tcp_mmap.c @@ -153,6 +153,19 @@ static void *mmap_large_buffer(size_t need, size_t *allocated) return buffer; } +static uint32_t tcp_info_get_rcv_mss(int fd) +{ + socklen_t sz = sizeof(struct tcp_info); + struct tcp_info info; + + if (getsockopt(fd, IPPROTO_TCP, TCP_INFO, &info, &sz)) { + fprintf(stderr, "Error fetching TCP_INFO\n"); + return 0; + } + + return info.tcpi_rcv_mss; +} + void *child_thread(void *arg) { unsigned char digest[SHA256_DIGEST_LENGTH]; @@ -288,7 +301,7 @@ end: total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec + 1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec; printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n" - " cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches\n", + " cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches, rcv_mss %u\n", total / (1024.0 * 1024.0), 100.0*total_mmap/total, (double)delta_usec / 1000000.0, @@ -296,7 +309,8 @@ end: (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0, (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0, (double)total_usec/mb, - ru.ru_nvcsw); + ru.ru_nvcsw, + tcp_info_get_rcv_mss(fd)); } error: munmap(buffer, buffer_sz); |