Hi,
Content-Disposition: inline; filename=ulogd-select-performance-improvement.diff
The previous code consumed quite lots of CPU cycles because of
inefficiently handling fd_sets.
This patch corrects that.
Signed-off-by: Holger Eitzenberger <holger@xxxxxxxxxxxxxxxx>
Index: ulogd-netfilter/src/select.c
===================================================================
--- ulogd-netfilter.orig/src/select.c
+++ ulogd-netfilter/src/select.c
@@ -24,86 +24,125 @@
#include <fcntl.h>
#include <ulogd/ulogd.h>
#include <ulogd/common.h>
+#include <ulogd/signal.h>
#include <ulogd/linuxlist.h>
-static int maxfd = 0;
+static fd_set readset, writeset, exceptset;
+static int maxfd = -1;
static LLIST_HEAD(ulogd_fds);
-int ulogd_register_fd(struct ulogd_fd *fd)
+
+static int
+set_nonblock(int fd)
{
int flags;
- /* make FD nonblocking */
- flags = fcntl(fd->fd, F_GETFL);
- if (flags < 0)
+ if ((flags = fcntl(fd, F_GETFL)) < 0)
return -1;
+
flags |= O_NONBLOCK;
- flags = fcntl(fd->fd, F_SETFL, flags);
- if (flags < 0)
+
+ if ((flags = fcntl(fd, F_SETFL, flags)) < 0)
+ return -1;
+
+ return 0;
+}
+
+int
+ulogd_register_fd(struct ulogd_fd *ufd)
+{
+ if (set_nonblock(ufd->fd) < 0)
return -1;
- /* Register FD */
- if (fd->fd > maxfd)
- maxfd = fd->fd;
+ if (ufd->when & ULOGD_FD_READ)
+ FD_SET(ufd->fd, &readset);
+
+ if (ufd->when & ULOGD_FD_WRITE)
+ FD_SET(ufd->fd, &writeset);
+
+ if (ufd->when & ULOGD_FD_EXCEPT)
+ FD_SET(ufd->fd, &exceptset);
+
+ if (ufd->fd > maxfd)
+ maxfd = ufd->fd;
- llist_add_tail(&fd->list, &ulogd_fds);
+ llist_add_tail(&ufd->list, &ulogd_fds);
return 0;
}
-void ulogd_unregister_fd(struct ulogd_fd *fd)
+void
+ulogd_unregister_fd(struct ulogd_fd *ufd)
{
- llist_del(&fd->list);
+ if (ufd->when & ULOGD_FD_READ)
+ FD_CLR(ufd->fd, &readset);
+
+ if (ufd->when & ULOGD_FD_WRITE)
+ FD_CLR(ufd->fd, &writeset);
+
+ if (ufd->when & ULOGD_FD_EXCEPT)
+ FD_CLR(ufd->fd, &exceptset);
+
+ llist_del(&ufd->list);
+
+ maxfd = -1;
+ llist_for_each_entry(ufd, &ulogd_fds, list) {
+ assert(ufd->fd >= 0);
+
+ if (ufd->fd > maxfd)
+ maxfd = ufd->fd;
+ }
}
-int ulogd_select_main()
+/* ulogd_dispatch() - dispatch events */
+int
+ulogd_dispatch(void)
{
- struct ulogd_fd *ufd;
- fd_set readset, writeset, exceptset;
- struct timeval tv = { .tv_sec = 1, };
- int i;
-
- FD_ZERO(&readset);
- FD_ZERO(&writeset);
- FD_ZERO(&exceptset);
+ fd_set rds_tmp, wrs_tmp, exs_tmp;
+ sigset_t curr_ss;
- /* prepare read and write fdsets */
- llist_for_each_entry(ufd, &ulogd_fds, list) {
- if (ufd->when & ULOGD_FD_READ)
- FD_SET(ufd->fd, &readset);
+ ulogd_get_sigset(&curr_ss);
- if (ufd->when & ULOGD_FD_WRITE)
- FD_SET(ufd->fd, &writeset);
+ pthread_sigmask(SIG_UNBLOCK, &curr_ss, NULL);
- if (ufd->when & ULOGD_FD_EXCEPT)
- FD_SET(ufd->fd, &exceptset);
- }
+ for (;;) {
+ struct ulogd_fd *ufd;
+ int n;
- again:
- i = select(maxfd+1, &readset, &writeset, &exceptset, &tv);
- if (i < 0) {
- if (errno == EINTR)
- goto again;
- }
+ again:
+ rds_tmp = readset;
+ wrs_tmp = writeset;
+ exs_tmp = exceptset;
- if (i > 0) {
- /* call registered callback functions */
- llist_for_each_entry(ufd, &ulogd_fds, list) {
- int flags = 0;
-
- if (FD_ISSET(ufd->fd, &readset))
- flags |= ULOGD_FD_READ;
+ n = select(maxfd+1, &rds_tmp, &wrs_tmp, &exs_tmp, NULL);
+ if (n < 0) {
+ if (errno == EINTR)
+ goto again;
- if (FD_ISSET(ufd->fd, &writeset))
- flags |= ULOGD_FD_WRITE;
+ ulogd_log(ULOGD_FATAL, "select: %m\n");
- if (FD_ISSET(ufd->fd, &exceptset))
- flags |= ULOGD_FD_EXCEPT;
+ break;
+ }
- if (flags)
- ufd->cb(ufd->fd, flags, ufd->data);
+ if (n > 0) {
+ /* call registered callback functions */
+ llist_for_each_entry(ufd, &ulogd_fds, list) {
+ int flags = 0;
+
+ if (FD_ISSET(ufd->fd, &rds_tmp))
+ flags |= ULOGD_FD_READ;
+
+ if (FD_ISSET(ufd->fd, &wrs_tmp))
+ flags |= ULOGD_FD_WRITE;
+
+ if (FD_ISSET(ufd->fd, &exs_tmp))
+ flags |= ULOGD_FD_EXCEPT;
+
+ if (flags)
+ ufd->cb(ufd->fd, flags, ufd->data);
+ }
}
}
- return i;
+ return 0;
}
Index: ulogd-netfilter/src/ulogd.c
===================================================================
--- ulogd-netfilter.orig/src/ulogd.c
+++ ulogd-netfilter/src/ulogd.c
@@ -727,32 +727,6 @@ out_buf:
return ret;
}
-
-static int ulogd_main_loop(void)
-{
- sigset_t curr;
- int ret = 0;
-
- ulogd_get_sigset(&curr);
-
- pthread_sigmask(SIG_UNBLOCK, &curr, NULL);
-
- for (;;) {
- ret = ulogd_select_main();
- if (ret == 0)
- continue;
-
- if (ret < 0) {
- ulogd_log(ULOGD_ERROR, "select returned %s\n",
- strerror(errno));
- break;
- }
- }
-
- return ret;
-}
-
-/* open the logfile */
static int logfile_open(const char *name)
{
if (name)
@@ -1112,7 +1086,7 @@ main(int argc, char* argv[])
ulogd_log(ULOGD_INFO, "entering main loop\n");
- ulogd_main_loop();
+ ulogd_dispatch();
return 0;
}
Index: ulogd-netfilter/include/ulogd/ulogd.h
===================================================================
--- ulogd-netfilter.orig/include/ulogd/ulogd.h
+++ ulogd-netfilter/include/ulogd/ulogd.h
@@ -243,7 +243,7 @@ struct ulogd_fd {
int ulogd_register_fd(struct ulogd_fd *ufd);
void ulogd_unregister_fd(struct ulogd_fd *ufd);
-int ulogd_select_main();
+int ulogd_dispatch(void);
/***********************************************************************
* timer handling (timer.c)
--
-
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