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[MAJOR] ev_epoll: do not rely on fd_sets anymore
The new epoll-based poller uses a list of changes in order to process only the fds which have changed.
This commit is contained in:
Willy Tarreau
parent
167d8b5953
commit
58094f2fd9
349
src/ev_epoll.c
349
src/ev_epoll.c
@ -16,6 +16,7 @@
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#include <common/compat.h>
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#include <common/config.h>
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#include <common/standard.h>
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#include <common/time.h>
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#include <types/fd.h>
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@ -35,67 +36,185 @@ _syscall4 (int, epoll_wait, int, epfd, struct epoll_event *, events, int, maxeve
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#include <sys/epoll.h>
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#endif
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/* This is what we store in a list. It consists in old values and fds to detect changes. */
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struct fd_chg {
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unsigned int prev:2; // previous state mask. New one is in fd_evts.
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unsigned int fd:30; // file descriptor
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};
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static fd_set *fd_evts[2];
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static fd_set *old_evts[2];
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static int nbchanges = 0; // number of changes pending
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static struct fd_chg *chg_list = NULL; // list of changes
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static struct fd_chg **chg_ptr = NULL; // per-fd changes
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/* Each 32-bit word contains 2-bit descriptors of the latest state for 16 FDs :
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* desc = (u32 >> (2*fd)) & 3
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* desc = 0 : FD not set
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* 1 : WRITE not set, READ set
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* 2 : WRITE set, READ not set
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* 3 : WRITE set, READ set
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*/
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static uint32_t *fd_evts;
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/* private data */
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static struct epoll_event *epoll_events;
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static int epoll_fd;
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/* This structure may be used for any purpose. Warning! do not use it in
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* recursive functions !
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*/
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static struct epoll_event ev;
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/* converts a direction to a single bitmask.
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* 0 => 1
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* 1 => 2
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*/
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#define DIR2MSK(dir) ((dir) + 1)
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/* converts an FD to an fd_evts offset and to a bit shift */
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#define FD2OFS(fd) ((uint32_t)(fd) >> 4)
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#define FD2BIT(fd) (((uint32_t)(fd) & 0xF) << 1)
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#define FD2MSK(fd) (3 << FD2BIT(fd))
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/*
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* Benchmarks performed on a Pentium-M notebook show that using functions
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* instead of the usual macros improve the FD_* performance by about 80%,
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* and that marking them regparm(2) adds another 20%.
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* Returns non-zero if direction <dir> is already set for <fd>.
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*/
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REGPRM2 static int __fd_is_set(const int fd, int dir)
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{
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return FD_ISSET(fd, fd_evts[dir]);
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return (fd_evts[FD2OFS(fd)] >> FD2BIT(fd)) & DIR2MSK(dir);
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}
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/*
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* Adds, mods or deletes <fd> according to current status and to new desired
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* mask <dmask> :
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*
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* 0 = nothing
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* 1 = EPOLLIN
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* 2 = EPOLLOUT
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* 3 = EPOLLIN | EPOLLOUT
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*
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*/
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static int dmsk2event[4] = { 0, EPOLLIN, EPOLLOUT, EPOLLIN | EPOLLOUT };
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REGPRM2 static void fd_flush_changes()
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{
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uint32_t ofs;
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int opcode;
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int prev, next;
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int chg, fd;
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for (chg = 0; chg < nbchanges; chg++) {
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prev = chg_list[chg].prev;
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fd = chg_list[chg].fd;
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chg_ptr[fd] = NULL;
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ofs = FD2OFS(fd);
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next = (fd_evts[ofs] >> FD2BIT(fd)) & 3;
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if (prev == next)
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/* if the value was unchanged, do nothing */
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continue;
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ev.events = dmsk2event[next];
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ev.data.fd = fd;
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if (prev) {
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if (!next) {
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/* we want to delete it now */
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opcode = EPOLL_CTL_DEL;
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} else {
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/* we want to switch it */
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opcode = EPOLL_CTL_MOD;
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}
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} else {
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/* the FD did not exist, let's add it */
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opcode = EPOLL_CTL_ADD;
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}
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epoll_ctl(epoll_fd, opcode, fd, &ev);
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}
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nbchanges = 0;
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}
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REGPRM2 static void alloc_chg_list(const int fd, int old_evt)
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{
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struct fd_chg *ptr;
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if (unlikely(chg_ptr[fd]))
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return;
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#if LIMIT_NUMBER_OF_CHANGES
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if (nbchanges > 2)
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fd_flush_changes();
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#endif
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ptr = &chg_list[nbchanges++];
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chg_ptr[fd] = ptr;
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ptr->fd = fd;
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ptr->prev = old_evt;
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}
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REGPRM2 static int __fd_set(const int fd, int dir)
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{
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FD_SET(fd, fd_evts[dir]);
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return 0;
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uint32_t ofs = FD2OFS(fd);
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uint32_t dmsk = DIR2MSK(dir);
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uint32_t old_evt;
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old_evt = fd_evts[ofs] >> FD2BIT(fd);
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old_evt &= 3;
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if (unlikely(old_evt & dmsk))
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return 0;
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alloc_chg_list(fd, old_evt);
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dmsk <<= FD2BIT(fd);
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fd_evts[ofs] |= dmsk;
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return 1;
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}
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REGPRM2 static int __fd_clr(const int fd, int dir)
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{
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FD_CLR(fd, fd_evts[dir]);
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return 0;
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uint32_t ofs = FD2OFS(fd);
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uint32_t dmsk = DIR2MSK(dir);
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uint32_t old_evt;
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old_evt = fd_evts[ofs] >> FD2BIT(fd);
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old_evt &= 3;
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if (unlikely(!(old_evt & dmsk)))
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return 0;
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alloc_chg_list(fd, old_evt);
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dmsk <<= FD2BIT(fd);
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fd_evts[ofs] &= ~dmsk;
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return 1;
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}
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REGPRM2 static int __fd_cond_s(const int fd, int dir)
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REGPRM1 static void __fd_rem(int fd)
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{
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int ret;
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ret = !FD_ISSET(fd, fd_evts[dir]);
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if (ret)
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FD_SET(fd, fd_evts[dir]);
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return ret;
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uint32_t ofs = FD2OFS(fd);
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if (unlikely(!((fd_evts[ofs] >> FD2BIT(fd)) & 3)))
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return;
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alloc_chg_list(fd, 0);
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fd_evts[ofs] &= ~FD2MSK(fd);
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return;
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}
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REGPRM2 static int __fd_cond_c(const int fd, int dir)
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/*
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* On valid epoll() implementations, a call to close() automatically removes
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* the fds. This means that the FD will appear as previously unset.
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*/
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REGPRM1 static void __fd_clo(int fd)
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{
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int ret;
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ret = FD_ISSET(fd, fd_evts[dir]);
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if (ret)
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FD_CLR(fd, fd_evts[dir]);
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return ret;
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}
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REGPRM1 static void __fd_rem(const int fd)
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{
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FD_CLR(fd, fd_evts[DIR_RD]);
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FD_CLR(fd, fd_evts[DIR_WR]);
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}
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REGPRM1 static void __fd_clo(const int fd)
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{
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FD_CLR(fd, fd_evts[DIR_RD]);
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FD_CLR(fd, fd_evts[DIR_WR]);
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FD_CLR(fd, old_evts[DIR_RD]);
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FD_CLR(fd, old_evts[DIR_WR]);
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struct fd_chg *ptr;
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fd_evts[FD2OFS(fd)] &= ~FD2MSK(fd);
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ptr = chg_ptr[fd];
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if (ptr) {
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ptr->prev = 0;
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chg_ptr[fd] = NULL;
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}
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return;
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}
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/*
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@ -105,93 +224,11 @@ REGPRM2 static void epoll_poll(struct poller *p, int wait_time)
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{
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int status;
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int fd;
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int count;
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int fds, count;
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int pr, pw, sr, sw;
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unsigned rn, ro, wn, wo; /* read new, read old, write new, write old */
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struct epoll_event ev;
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if (likely(nbchanges))
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fd_flush_changes();
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for (fds = 0; (fds << INTBITS) < maxfd; fds++) {
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rn = ((int*)fd_evts[DIR_RD])[fds]; ro = ((int*)old_evts[DIR_RD])[fds];
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wn = ((int*)fd_evts[DIR_WR])[fds]; wo = ((int*)old_evts[DIR_WR])[fds];
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if ((ro^rn) | (wo^wn)) {
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for (count = 0, fd = fds << INTBITS; count < (1<<INTBITS) && fd < maxfd; count++, fd++) {
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#define FDSETS_ARE_INT_ALIGNED
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#ifdef FDSETS_ARE_INT_ALIGNED
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#define WE_REALLY_NOW_THAT_FDSETS_ARE_INTS
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#ifdef WE_REALLY_NOW_THAT_FDSETS_ARE_INTS
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pr = (ro >> count) & 1;
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pw = (wo >> count) & 1;
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sr = (rn >> count) & 1;
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sw = (wn >> count) & 1;
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#else
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pr = FD_ISSET(fd&((1<<INTBITS)-1), (typeof(fd_set*))&ro);
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pw = FD_ISSET(fd&((1<<INTBITS)-1), (typeof(fd_set*))&wo);
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sr = FD_ISSET(fd&((1<<INTBITS)-1), (typeof(fd_set*))&rn);
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sw = FD_ISSET(fd&((1<<INTBITS)-1), (typeof(fd_set*))&wn);
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#endif
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#else
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pr = FD_ISSET(fd, old_evts[DIR_RD]);
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pw = FD_ISSET(fd, old_evts[DIR_WR]);
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sr = FD_ISSET(fd, fd_evts[DIR_RD]);
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sw = FD_ISSET(fd, fd_evts[DIR_WR]);
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#endif
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if (!((sr^pr) | (sw^pw)))
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continue;
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ev.events = (sr ? EPOLLIN : 0) | (sw ? EPOLLOUT : 0);
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ev.data.fd = fd;
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#ifdef EPOLL_CTL_MOD_WORKAROUND
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/* I encountered a rarely reproducible problem with
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* EPOLL_CTL_MOD where a modified FD (systematically
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* the one in epoll_events[0], fd#7) would sometimes
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* be set EPOLL_OUT while asked for a read ! This is
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* with the 2.4 epoll patch. The workaround is to
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* delete then recreate in case of modification.
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* This is in 2.4 up to epoll-lt-0.21 but not in 2.6
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* nor RHEL kernels.
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*/
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if ((pr | pw) && fdtab[fd].state != FD_STCLOSE)
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epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, &ev);
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if ((sr | sw))
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epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev);
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#else
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if ((pr | pw)) {
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/* the file-descriptor already exists... */
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if ((sr | sw)) {
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/* ...and it will still exist */
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if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &ev) < 0) {
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// perror("epoll_ctl(MOD)");
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// exit(1);
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}
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} else {
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/* ...and it will be removed */
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if (fdtab[fd].state != FD_STCLOSE &&
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epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fd, &ev) < 0) {
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// perror("epoll_ctl(DEL)");
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// exit(1);
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}
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}
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} else {
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/* the file-descriptor did not exist, let's add it */
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if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev) < 0) {
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// perror("epoll_ctl(ADD)");
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// exit(1);
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}
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}
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#endif // EPOLL_CTL_MOD_WORKAROUND
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}
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((int*)old_evts[DIR_RD])[fds] = rn;
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((int*)old_evts[DIR_WR])[fds] = wn;
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}
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}
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/* now let's wait for events */
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status = epoll_wait(epoll_fd, epoll_events, maxfd, wait_time);
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tv_now(&now);
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@ -199,14 +236,14 @@ REGPRM2 static void epoll_poll(struct poller *p, int wait_time)
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for (count = 0; count < status; count++) {
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fd = epoll_events[count].data.fd;
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if (FD_ISSET(fd, fd_evts[DIR_RD])) {
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if ((fd_evts[FD2OFS(fd)] >> FD2BIT(fd)) & DIR2MSK(DIR_RD)) {
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if (fdtab[fd].state == FD_STCLOSE)
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continue;
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if (epoll_events[count].events & ( EPOLLIN | EPOLLERR | EPOLLHUP ))
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fdtab[fd].cb[DIR_RD].f(fd);
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}
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if (FD_ISSET(fd, fd_evts[DIR_WR])) {
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if ((fd_evts[FD2OFS(fd)] >> FD2BIT(fd)) & DIR2MSK(DIR_WR)) {
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if (fdtab[fd].state == FD_STCLOSE)
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continue;
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if (epoll_events[count].events & ( EPOLLOUT | EPOLLERR | EPOLLHUP ))
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@ -222,11 +259,11 @@ REGPRM2 static void epoll_poll(struct poller *p, int wait_time)
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*/
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REGPRM1 static int epoll_init(struct poller *p)
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{
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__label__ fail_pwevt, fail_prevt, fail_swevt, fail_srevt, fail_ee, fail_fd;
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__label__ fail_chg_ptr, fail_chg_list, fail_fdevt, fail_ee, fail_fd;
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int fd_set_bytes;
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p->private = NULL;
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fd_set_bytes = sizeof(fd_set) * (global.maxsock + FD_SETSIZE - 1) / FD_SETSIZE;
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fd_set_bytes = 4 * (global.maxsock + 15) / 16;
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epoll_fd = epoll_create(global.maxsock + 1);
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if (epoll_fd < 0)
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@ -238,27 +275,24 @@ REGPRM1 static int epoll_init(struct poller *p)
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if (epoll_events == NULL)
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goto fail_ee;
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if ((old_evts[DIR_RD] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
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goto fail_prevt;
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if ((fd_evts = (uint32_t *)calloc(1, fd_set_bytes)) == NULL)
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goto fail_fdevt;
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if ((old_evts[DIR_WR] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
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goto fail_pwevt;
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if ((fd_evts[DIR_RD] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
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goto fail_srevt;
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chg_list = (struct fd_chg *)calloc(1, sizeof(struct fd_chg) * global.maxsock);
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if (chg_list == NULL)
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goto fail_chg_list;
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if ((fd_evts[DIR_WR] = (fd_set *)calloc(1, fd_set_bytes)) == NULL)
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goto fail_swevt;
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chg_ptr = (struct fd_chg **)calloc(1, sizeof(struct fd_chg*) * global.maxsock);
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if (chg_ptr == NULL)
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goto fail_chg_ptr;
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return 1;
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fail_swevt:
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free(fd_evts[DIR_RD]);
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fail_srevt:
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free(old_evts[DIR_WR]);
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fail_pwevt:
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free(old_evts[DIR_RD]);
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fail_prevt:
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fail_chg_ptr:
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free(chg_list);
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fail_chg_list:
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free(fd_evts);
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fail_fdevt:
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free(epoll_events);
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fail_ee:
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close(epoll_fd);
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@ -274,24 +308,25 @@ REGPRM1 static int epoll_init(struct poller *p)
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*/
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REGPRM1 static void epoll_term(struct poller *p)
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{
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if (fd_evts[DIR_WR])
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free(fd_evts[DIR_WR]);
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if (fd_evts[DIR_RD])
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free(fd_evts[DIR_RD]);
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if (old_evts[DIR_WR])
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free(old_evts[DIR_WR]);
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if (old_evts[DIR_RD])
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free(old_evts[DIR_RD]);
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fd_flush_changes();
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if (chg_ptr)
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free(chg_ptr);
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if (chg_list)
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free(chg_list);
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if (fd_evts)
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free(fd_evts);
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if (epoll_events)
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free(epoll_events);
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close(epoll_fd);
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epoll_fd = 0;
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chg_ptr = NULL;
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chg_list = NULL;
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fd_evts = NULL;
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epoll_events = NULL;
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p->private = NULL;
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p->pref = 0;
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}
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@ -324,13 +359,13 @@ int epoll_register(struct poller *p)
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p->init = epoll_init;
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p->term = epoll_term;
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p->poll = epoll_poll;
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p->is_set = __fd_is_set;
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p->set = __fd_set;
|
||||
p->clr = __fd_clr;
|
||||
|
||||
p->is_set = __fd_is_set;
|
||||
p->cond_s = p->set = __fd_set;
|
||||
p->cond_c = p->clr = __fd_clr;
|
||||
p->rem = __fd_rem;
|
||||
p->clo = __fd_clo;
|
||||
p->cond_s = __fd_cond_s;
|
||||
p->cond_c = __fd_cond_c;
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user