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CLEANUP: polling: gcc doesn't always optimize constants away

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In ev_poll and ev_epoll, we have a bit-to-bit mapping between the POLL_
constants and the FD_POLL_ constants. A comment said that gcc was able
to detect this and to automatically apply a mask. Things have possibly
changed since the output assembly doesn't always reflect this. So let's
perform an explicit assignment when bits are equal.
This commit is contained in:
Willy Tarreau 2012-12-13 22:26:37 +01:00
parent 04281bd1ad
commit 462c7206bc
2 changed files with 28 additions and 12 deletions
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21
src/ev_epoll.c
View File

@ -144,15 +144,22 @@ REGPRM2 static void _do_poll(struct poller *p, int exp)
continue; continue;
/* it looks complicated but gcc can optimize it away when constants /* it looks complicated but gcc can optimize it away when constants
* have same values. * have same values... In fact it depends on gcc :-(
*/ */
fdtab[fd].ev &= FD_POLL_STICKY; fdtab[fd].ev &= FD_POLL_STICKY;
fdtab[fd].ev |= if (EPOLLIN == FD_POLL_IN && EPOLLOUT == FD_POLL_OUT &&
((e & EPOLLIN ) ? FD_POLL_IN : 0) | EPOLLPRI == FD_POLL_PRI && EPOLLERR == FD_POLL_ERR &&
((e & EPOLLPRI) ? FD_POLL_PRI : 0) | EPOLLHUP == FD_POLL_HUP) {
((e & EPOLLOUT) ? FD_POLL_OUT : 0) | fdtab[fd].ev |= e & (EPOLLIN|EPOLLOUT|EPOLLPRI|EPOLLERR|EPOLLHUP);
((e & EPOLLERR) ? FD_POLL_ERR : 0) | }
((e & EPOLLHUP) ? FD_POLL_HUP : 0); else {
fdtab[fd].ev |=
((e & EPOLLIN ) ? FD_POLL_IN : 0) |
((e & EPOLLPRI) ? FD_POLL_PRI : 0) |
((e & EPOLLOUT) ? FD_POLL_OUT : 0) |
((e & EPOLLERR) ? FD_POLL_ERR : 0) |
((e & EPOLLHUP) ? FD_POLL_HUP : 0);
}
if (fdtab[fd].iocb && fdtab[fd].owner && fdtab[fd].ev) { if (fdtab[fd].iocb && fdtab[fd].owner && fdtab[fd].ev) {
int new_updt, old_updt = fd_nbupdt; /* Save number of updates to detect creation of new FDs. */ int new_updt, old_updt = fd_nbupdt; /* Save number of updates to detect creation of new FDs. */

19
src/ev_poll.c
View File

@ -154,12 +154,21 @@ REGPRM2 static void _do_poll(struct poller *p, int exp)
if (!fdtab[fd].owner) if (!fdtab[fd].owner)
continue; continue;
/* it looks complicated but gcc can optimize it away when constants
* have same values... In fact it depends on gcc :-(
*/
fdtab[fd].ev &= FD_POLL_STICKY; fdtab[fd].ev &= FD_POLL_STICKY;
fdtab[fd].ev |= if (POLLIN == FD_POLL_IN && POLLOUT == FD_POLL_OUT &&
((e & POLLIN ) ? FD_POLL_IN : 0) | POLLERR == FD_POLL_ERR && POLLHUP == FD_POLL_HUP) {
((e & POLLOUT) ? FD_POLL_OUT : 0) | fdtab[fd].ev |= e & (POLLIN|POLLOUT|POLLERR|POLLHUP);
((e & POLLERR) ? FD_POLL_ERR : 0) | }
((e & POLLHUP) ? FD_POLL_HUP : 0); else {
fdtab[fd].ev |=
((e & POLLIN ) ? FD_POLL_IN : 0) |
((e & POLLOUT) ? FD_POLL_OUT : 0) |
((e & POLLERR) ? FD_POLL_ERR : 0) |
((e & POLLHUP) ? FD_POLL_HUP : 0);
}
if (fdtab[fd].iocb && fdtab[fd].owner && fdtab[fd].ev) { if (fdtab[fd].iocb && fdtab[fd].owner && fdtab[fd].ev) {
/* Mark the events as speculative before processing /* Mark the events as speculative before processing