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cpu-usage: reduce cpu usage when idle

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This commit is contained in:
Nick Peng
2022-10-27 21:38:04 +08:00
parent 391ef310b4
commit 7b8ff57773
4 changed files with 209 additions and 13 deletions
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101
src/dns_server.c
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@@ -40,6 +40,7 @@
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/eventfd.h>
#include <sys/socket.h>
#include <sys/types.h>
@@ -246,6 +247,7 @@ struct dns_request {
struct dns_server {
atomic_t run;
int epoll_fd;
int event_fd;
struct list_head conn_list;
/* dns request list */
@@ -269,7 +271,14 @@ static void _dns_server_request_get(struct dns_request *request);
static void _dns_server_request_release(struct dns_request *request);
static void _dns_server_request_release_complete(struct dns_request *request, int do_complete);
static int _dns_server_reply_passthrouth(struct dns_server_post_context *context);
static int _dns_server_do_query(struct dns_request *request);
static int _dns_server_do_query(struct dns_request *request, int skip_notify_event);
static void _dns_server_wakup_thread(void)
{
uint64_t u = 1;
int unused __attribute__((unused));
unused = write(server.event_fd, &u, sizeof(u));
}
static int _dns_server_forward_request(unsigned char *inpacket, int inpacket_len)
{
@@ -4054,7 +4063,7 @@ static int _dns_server_query_dualstack(struct dns_request *request)
request_dualstack->dualstack_request = request;
_dns_server_request_set_callback(request_dualstack, dns_server_dualstack_callback, request);
request->request_wait++;
ret = _dns_server_do_query(request_dualstack);
ret = _dns_server_do_query(request_dualstack, 0);
if (ret != 0) {
request->request_wait--;
tlog(TLOG_ERROR, "do query %s type %d failed.\n", request->domain, qtype);
@@ -4074,7 +4083,7 @@ errout:
return ret;
}
static int _dns_server_do_query(struct dns_request *request)
static int _dns_server_do_query(struct dns_request *request, int skip_notify_event)
{
int ret = -1;
const char *group_name = NULL;
@@ -4150,6 +4159,9 @@ static int _dns_server_do_query(struct dns_request *request)
_dns_server_setup_query_option(request, &options);
pthread_mutex_lock(&server.request_list_lock);
if (list_empty(&server.request_list) && skip_notify_event == 1) {
_dns_server_wakup_thread();
}
list_add_tail(&request->list, &server.request_list);
pthread_mutex_unlock(&server.request_list_lock);
@@ -4275,7 +4287,7 @@ static int _dns_server_recv(struct dns_server_conn_head *conn, unsigned char *in
_dns_server_request_set_client(request, conn);
_dns_server_request_set_client_addr(request, from, from_len);
_dns_server_request_set_id(request, packet->head.id);
ret = _dns_server_do_query(request);
ret = _dns_server_do_query(request, 1);
if (ret != 0) {
tlog(TLOG_ERROR, "do query %s failed.\n", request->domain);
goto errout;
@@ -4327,7 +4339,7 @@ static int _dns_server_prefetch_request(char *domain, dns_type_t qtype, int expi
request->qtype = qtype;
_dns_server_setup_server_query_options(request, server_query_option);
_dns_server_request_set_enable_prefetch(request, expired_domain);
ret = _dns_server_do_query(request);
ret = _dns_server_do_query(request, 0);
if (ret != 0) {
tlog(TLOG_ERROR, "do query %s failed.\n", request->domain);
goto errout;
@@ -4359,7 +4371,7 @@ int dns_server_query(const char *domain, int qtype, struct dns_server_query_opti
request->qtype = qtype;
_dns_server_setup_server_query_options(request, server_query_option);
_dns_server_request_set_callback(request, callback, user_ptr);
ret = _dns_server_do_query(request);
ret = _dns_server_do_query(request, 0);
if (ret != 0) {
tlog(TLOG_ERROR, "do query %s failed.\n", domain);
goto errout;
@@ -4865,14 +4877,12 @@ static void _dns_server_period_run_second(void)
}
}
static void _dns_server_period_run(void)
static void _dns_server_period_run(unsigned int msec)
{
struct dns_request *request = NULL;
struct dns_request *tmp = NULL;
static unsigned int msec = 0;
LIST_HEAD(check_list);
msec++;
if (msec % 10 == 0) {
_dns_server_period_run_second();
}
@@ -4940,22 +4950,50 @@ int dns_server_run(void)
int num = 0;
int i = 0;
unsigned long now = {0};
unsigned long last = {0};
unsigned int msec = 0;
int sleep = 100;
int sleep_time = 0;
unsigned long expect_time = 0;
sleep_time = sleep;
now = get_tick_count() - sleep;
last = now;
expect_time = now + sleep;
while (atomic_read(&server.run)) {
now = get_tick_count();
if (sleep_time > 0) {
sleep_time -= now - last;
if (sleep_time <= 0) {
sleep_time = 0;
}
int cnt = sleep_time / sleep;
msec -= cnt;
expect_time -= cnt * sleep;
sleep_time -= cnt * sleep;
}
last = now;
if (now >= expect_time) {
_dns_server_period_run();
msec++;
_dns_server_period_run(msec);
sleep_time = sleep - (now - expect_time);
if (sleep_time < 0) {
sleep_time = 0;
expect_time = now;
}
/* When server is idle, the sleep time is 1000ms, to reduce CPU usage */
pthread_mutex_lock(&server.request_list_lock);
if (list_empty(&server.request_list)) {
int cnt = 10 - (msec % 10) - 1;
sleep_time += sleep * cnt;
msec += cnt;
/* sleep to next second */
expect_time += sleep * cnt;
}
pthread_mutex_unlock(&server.request_list_lock);
expect_time += sleep;
}
@@ -4971,6 +5009,14 @@ int dns_server_run(void)
for (i = 0; i < num; i++) {
struct epoll_event *event = &events[i];
/* read event */
if (event->data.fd == server.event_fd) {
uint64_t value;
int unused __attribute__((unused));
unused = read(server.event_fd, &value, sizeof(uint64_t));
continue;
}
struct dns_server_conn_head *conn_head = event->data.ptr;
if (conn_head == NULL) {
tlog(TLOG_ERROR, "invalid fd\n");
@@ -5294,6 +5340,31 @@ static int _dns_server_cache_save(void)
return 0;
}
static int _dns_server_init_wakeup_event(void)
{
int fdevent = -1;
fdevent = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
if (fdevent < 0) {
tlog(TLOG_ERROR, "create eventfd failed, %s\n", strerror(errno));
goto errout;
}
struct epoll_event event;
memset(&event, 0, sizeof(event));
event.events = EPOLLIN | EPOLLERR;
event.data.fd = fdevent;
if (epoll_ctl(server.epoll_fd, EPOLL_CTL_ADD, fdevent, &event) != 0) {
tlog(TLOG_ERROR, "set eventfd failed, %s\n", strerror(errno));
goto errout;
}
server.event_fd = fdevent;
return 0;
errout:
return -1;
}
int dns_server_init(void)
{
pthread_attr_t attr;
@@ -5344,6 +5415,11 @@ int dns_server_init(void)
tlog(TLOG_INFO, "%s",
(is_ipv6_ready) ? "IPV6 is ready, enable IPV6 features" : "IPV6 is not ready, disable IPV6 features");
if (_dns_server_init_wakeup_event() != 0) {
tlog(TLOG_ERROR, "init wakeup event failed.");
goto errout;
}
return 0;
errout:
atomic_set(&server.run, 0);
@@ -5363,10 +5439,15 @@ errout:
void dns_server_stop(void)
{
atomic_set(&server.run, 0);
_dns_server_wakup_thread();
}
void dns_server_exit(void)
{
if (server.event_fd > 0) {
close(server.event_fd);
server.event_fd = -1;
}
_dns_server_close_socket();
_dns_server_cache_save();
_dns_server_request_remove_all();