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server/main: Automatic select() fd debugger

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This commit is contained in:
Perttu Ahola 2014-09-18 17:26:01 +03:00
parent 8d0b729adc
commit 446f98d94f
1 changed files with 36 additions and 1 deletions
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37
src/server/main.cpp
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@ -106,6 +106,10 @@ int main(int argc, char *argv[])
// Main loop
uint64_t next_tick_us = get_timeofday_us();
uint64_t t_per_tick = 1000 * 100;
set_<int> attempt_bad_fds;
int last_added_attempt_bad_fd = -42;
set_<int> bad_fds;
size_t num_consequent_valid_selects = 0;
while(!g_sigint_received){
struct timeval tv;
tv.tv_sec = 0;
@ -115,7 +119,14 @@ int main(int argc, char *argv[])
FD_ZERO(&rfds);
sv_<int> sockets = state->get_sockets();
int fd_max = 0;
if(!attempt_bad_fds.empty() || !bad_fds.empty()){
log_w("main", "Ignoring fds %s and %s out of all %s",
cs(dump(attempt_bad_fds)), cs(dump(bad_fds)),
cs(dump(sockets)));
}
for(int fd : sockets){
if(attempt_bad_fds.count(fd) || bad_fds.count(fd))
continue;
FD_SET(fd, &rfds);
if(fd > fd_max)
fd_max = fd;
@ -124,9 +135,25 @@ int main(int argc, char *argv[])
int r = select(fd_max + 1, &rfds, NULL, NULL, &tv);
if(r == -1){
// Error
log_w("main", "select() returned -1: %s", strerror(errno));
num_consequent_valid_selects = 0;
log_w("main", "select() returned -1: %s (fds: %s)",
strerror(errno), cs(dump(sockets)));
if(errno == EBADF || errno == EINTR){
// These are temporary errors
// Try to find out which socket is doing this
if(attempt_bad_fds.size() == sockets.size()){
throw Exception("All fds are bad");
} else {
for(;;){
int fd = sockets[rand() % sockets.size()];
if(attempt_bad_fds.count(fd) == 0){
log_w("main", "Trying to ignore fd=%i", fd);
attempt_bad_fds.insert(fd);
last_added_attempt_bad_fd = fd;
break;
}
}
}
} else {
// Don't consume 100% CPU and flood logs
usleep(1000 * 100);
@ -134,8 +161,10 @@ int main(int argc, char *argv[])
}
} else if(r == 0){
// Nothing happened
num_consequent_valid_selects++;
} else {
// Something happened
num_consequent_valid_selects++;
for(int fd : sockets){
if(FD_ISSET(fd, &rfds)){
log_d("main", "FD_ISSET: %i", fd);
@ -144,6 +173,12 @@ int main(int argc, char *argv[])
}
}
if(!attempt_bad_fds.empty() && num_consequent_valid_selects > 5){
log_w("main", "Found bad fd: %d", last_added_attempt_bad_fd);
bad_fds.insert(last_added_attempt_bad_fd);
attempt_bad_fds.clear();
}
uint64_t current_us = get_timeofday_us();
if(current_us >= next_tick_us){
next_tick_us += t_per_tick;