MEDIUM: polling: start to move maxfd computation to the pollers
Since only select() and poll() still make use of maxfd, let's move
its computation right there in the pollers themselves, and only
during each fd update pass. The computation doesn't need a lock
anymore, only a few atomic ops. It will be accurate, be done much
less often and will not be required anymore in the FD's fast patch.
This provides a small performance increase of about 1% in connection
rate when using epoll since we get rid of this computation which was
performed under a lock.
diff --git a/src/fd.c b/src/fd.c
index 4397f6e..1fa170b 100644
--- a/src/fd.c
+++ b/src/fd.c
@@ -160,7 +160,6 @@
struct fdtab *fdtab = NULL; /* array of all the file descriptors */
struct fdinfo *fdinfo = NULL; /* less-often used infos for file descriptors */
-int maxfd; /* # of the highest fd + 1 */
int totalconn; /* total # of terminated sessions */
int actconn; /* # of active sessions */
@@ -179,7 +178,7 @@
__decl_hathreads(HA_RWLOCK_T fdcache_lock); /* global lock to protect fd_cache array */
__decl_hathreads(HA_SPINLOCK_T poll_lock); /* global lock to protect poll info */
-/* Deletes an FD from the fdsets, and recomputes the maxfd limit.
+/* Deletes an FD from the fdsets.
* The file descriptor is also closed.
*/
static void fd_dodelete(int fd, int do_close)
@@ -207,14 +206,9 @@
close(fd);
}
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
-
- HA_SPIN_LOCK(FDTAB_LOCK, &fdtab_lock);
- while ((maxfd-1 >= 0) && !fdtab[maxfd-1].owner)
- maxfd--;
- HA_SPIN_UNLOCK(FDTAB_LOCK, &fdtab_lock);
}
-/* Deletes an FD from the fdsets, and recomputes the maxfd limit.
+/* Deletes an FD from the fdsets.
* The file descriptor is also closed.
*/
void fd_delete(int fd)
@@ -222,7 +216,7 @@
fd_dodelete(fd, 1);
}
-/* Deletes an FD from the fdsets, and recomputes the maxfd limit.
+/* Deletes an FD from the fdsets.
* The file descriptor is kept open.
*/
void fd_remove(int fd)