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selftests/net: make so_txtime more robust to timer variance

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[ Upstream commit ea6a547669b37453f2b1a5d85188d75b3613dfaa ]

The SO_TXTIME test depends on accurate timers. In some virtualized
environments the test has been reported to be flaky. This is easily
reproduced by disabling kvm acceleration in Qemu.

Allow greater variance in a run and retry to further reduce flakiness.

Observed errors are one of two kinds: either the packet arrives too
early or late at recv(), or it was dropped in the qdisc itself and the
recv() call times out.

In the latter case, the qdisc queues a notification to the error
queue of the send socket. Also explicitly report this cause.

Link: https://lore.kernel.org/netdev/CA+FuTSdYOnJCsGuj43xwV1jxvYsaoa_LzHQF9qMyhrkLrivxKw@mail.gmail.com
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Willem de Bruijn 2019-12-12 11:36:46 -05:00 committed by Greg Kroah-Hartman
parent 687ef9c269
commit cf03458ab2
2 changed files with 88 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

84
tools/testing/selftests/net/so_txtime.c
View File

@ -12,7 +12,11 @@
#include <arpa/inet.h>
#include <error.h>
#include <errno.h>
#include <inttypes.h>
#include <linux/net_tstamp.h>
#include <linux/errqueue.h>
#include <linux/ipv6.h>
#include <linux/tcp.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
@ -28,7 +32,7 @@ static int cfg_clockid = CLOCK_TAI;
static bool cfg_do_ipv4;
static bool cfg_do_ipv6;
static uint16_t cfg_port = 8000;
static int cfg_variance_us = 2000;
static int cfg_variance_us = 4000;
static uint64_t glob_tstart;
@ -43,6 +47,9 @@ static struct timed_send cfg_in[MAX_NUM_PKT];
static struct timed_send cfg_out[MAX_NUM_PKT];
static int cfg_num_pkt;
static int cfg_errq_level;
static int cfg_errq_type;
static uint64_t gettime_ns(void)
{
struct timespec ts;
@ -90,13 +97,15 @@ static void do_send_one(int fdt, struct timed_send *ts)
}
static void do_recv_one(int fdr, struct timed_send *ts)
static bool do_recv_one(int fdr, struct timed_send *ts)
{
int64_t tstop, texpect;
char rbuf[2];
int ret;
ret = recv(fdr, rbuf, sizeof(rbuf), 0);
if (ret == -1 && errno == EAGAIN)
return true;
if (ret == -1)
error(1, errno, "read");
if (ret != 1)
@ -113,6 +122,8 @@ static void do_recv_one(int fdr, struct timed_send *ts)
if (labs(tstop - texpect) > cfg_variance_us)
error(1, 0, "exceeds variance (%d us)", cfg_variance_us);
return false;
}
static void do_recv_verify_empty(int fdr)
@ -125,12 +136,70 @@ static void do_recv_verify_empty(int fdr)
error(1, 0, "recv: not empty as expected (%d, %d)", ret, errno);
}
static void do_recv_errqueue_timeout(int fdt)
{
char control[CMSG_SPACE(sizeof(struct sock_extended_err)) +
CMSG_SPACE(sizeof(struct sockaddr_in6))] = {0};
char data[sizeof(struct ipv6hdr) +
sizeof(struct tcphdr) + 1];
struct sock_extended_err *err;
struct msghdr msg = {0};
struct iovec iov = {0};
struct cmsghdr *cm;
int64_t tstamp = 0;
int ret;
iov.iov_base = data;
iov.iov_len = sizeof(data);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = control;
msg.msg_controllen = sizeof(control);
while (1) {
ret = recvmsg(fdt, &msg, MSG_ERRQUEUE);
if (ret == -1 && errno == EAGAIN)
break;
if (ret == -1)
error(1, errno, "errqueue");
if (msg.msg_flags != MSG_ERRQUEUE)
error(1, 0, "errqueue: flags 0x%x\n", msg.msg_flags);
cm = CMSG_FIRSTHDR(&msg);
if (cm->cmsg_level != cfg_errq_level ||
cm->cmsg_type != cfg_errq_type)
error(1, 0, "errqueue: type 0x%x.0x%x\n",
cm->cmsg_level, cm->cmsg_type);
err = (struct sock_extended_err *)CMSG_DATA(cm);
if (err->ee_origin != SO_EE_ORIGIN_TXTIME)
error(1, 0, "errqueue: origin 0x%x\n", err->ee_origin);
if (err->ee_code != ECANCELED)
error(1, 0, "errqueue: code 0x%x\n", err->ee_code);
tstamp = ((int64_t) err->ee_data) << 32 | err->ee_info;
tstamp -= (int64_t) glob_tstart;
tstamp /= 1000 * 1000;
fprintf(stderr, "send: pkt %c at %" PRId64 "ms dropped\n",
data[ret - 1], tstamp);
msg.msg_flags = 0;
msg.msg_controllen = sizeof(control);
}
error(1, 0, "recv: timeout");
}
static void setsockopt_txtime(int fd)
{
struct sock_txtime so_txtime_val = { .clockid = cfg_clockid };
struct sock_txtime so_txtime_val_read = { 0 };
socklen_t vallen = sizeof(so_txtime_val);
so_txtime_val.flags = SOF_TXTIME_REPORT_ERRORS;
if (setsockopt(fd, SOL_SOCKET, SO_TXTIME,
&so_txtime_val, sizeof(so_txtime_val)))
error(1, errno, "setsockopt txtime");
@ -194,7 +263,8 @@ static void do_test(struct sockaddr *addr, socklen_t alen)
for (i = 0; i < cfg_num_pkt; i++)
do_send_one(fdt, &cfg_in[i]);
for (i = 0; i < cfg_num_pkt; i++)
do_recv_one(fdr, &cfg_out[i]);
if (do_recv_one(fdr, &cfg_out[i]))
do_recv_errqueue_timeout(fdt);
do_recv_verify_empty(fdr);
@ -280,6 +350,10 @@ int main(int argc, char **argv)
addr6.sin6_family = AF_INET6;
addr6.sin6_port = htons(cfg_port);
addr6.sin6_addr = in6addr_loopback;
cfg_errq_level = SOL_IPV6;
cfg_errq_type = IPV6_RECVERR;
do_test((void *)&addr6, sizeof(addr6));
}
@ -289,6 +363,10 @@ int main(int argc, char **argv)
addr4.sin_family = AF_INET;
addr4.sin_port = htons(cfg_port);
addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
cfg_errq_level = SOL_IP;
cfg_errq_type = IP_RECVERR;
do_test((void *)&addr4, sizeof(addr4));
}

9
tools/testing/selftests/net/so_txtime.sh
View File

@ -5,7 +5,12 @@
# Run in network namespace
if [[ $# -eq 0 ]]; then
./in_netns.sh $0 __subprocess
if ! ./in_netns.sh $0 __subprocess; then
# test is time sensitive, can be flaky
echo "test failed: retry once"
./in_netns.sh $0 __subprocess
fi
exit $?
fi
@ -18,7 +23,7 @@ tc qdisc add dev lo root fq
./so_txtime -4 -6 -c mono a,10,b,20 a,10,b,20
./so_txtime -4 -6 -c mono a,20,b,10 b,20,a,20
if tc qdisc replace dev lo root etf clockid CLOCK_TAI delta 200000; then
if tc qdisc replace dev lo root etf clockid CLOCK_TAI delta 400000; then
! ./so_txtime -4 -6 -c tai a,-1 a,-1
! ./so_txtime -4 -6 -c tai a,0 a,0
./so_txtime -4 -6 -c tai a,10 a,10