extpoll use hashtable for fd tracking
This implements a much faster, hashtable-based tracking scheme for external poll fds. Signed-off-by: Andy Green <andy.green@linaro.org>
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Andy Green
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29da6d9443
commit
5fc460cd41
1 changed files with 114 additions and 24 deletions
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@ -25,6 +25,7 @@
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#include <getopt.h>
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#include <string.h>
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#include <sys/time.h>
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#include <assert.h>
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#include "../lib/libwebsockets.h"
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@ -37,9 +38,47 @@ static int close_testing;
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#else
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#define MAX_POLL_ELEMENTS (MAX_CLIENTS)
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#endif
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struct poll_hash_map {
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int fd;
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int index;
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};
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#define POLL_HASH_BITS 8
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#define POLL_HASH_BUCKETS (1 << POLL_HASH_BITS)
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#define POLL_ENTRIES_PER_BUCKET (MAX_POLL_ELEMENTS / (1 << (POLL_HASH_BITS - 2)))
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#define POLL_HASH(num) (num & (POLL_HASH_BUCKETS - 1))
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struct pollfd pollfds[MAX_POLL_ELEMENTS];
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struct poll_hash_map pollfd_maps[POLL_HASH_BUCKETS][POLL_ENTRIES_PER_BUCKET];
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int pollfd_count[POLL_HASH_BUCKETS];
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int count_pollfds = 0;
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#endif
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static int find_poll_map_index(int hash, int fd)
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{
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int n;
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for (n = 0; n < pollfd_count[hash]; n++)
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if (pollfd_maps[hash][n].fd == fd)
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return n;
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return -1;
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}
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static int find_pollfd_index(int fd)
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{
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int n;
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int hash = POLL_HASH(fd);
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n = find_poll_map_index(hash, fd);
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if (n < 0)
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return n;
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return pollfd_maps[hash][n].index;
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}
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#endif /* EXTERNAL_POLL */
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/*
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* This demo server shows how to use libwebsockets for one or more
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@ -80,7 +119,9 @@ static int callback_http(struct libwebsocket_context *context,
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char client_name[128];
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char client_ip[128];
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#ifdef EXTERNAL_POLL
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int n;
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int n, m, m1;
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int hash, hash1;
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int fd = (int)(long)user;
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#endif
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switch (reason) {
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@ -139,8 +180,20 @@ static int callback_http(struct libwebsocket_context *context,
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*/
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case LWS_CALLBACK_ADD_POLL_FD:
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if (count_pollfds == MAX_POLL_ELEMENTS)
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if (count_pollfds == MAX_POLL_ELEMENTS) {
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fprintf(stderr, "LWS_CALLBACK_ADD_POLL_FD: too many sockets to track\n");
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return 1;
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}
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hash = POLL_HASH(fd);
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if (pollfd_count[hash] == POLL_ENTRIES_PER_BUCKET) {
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fprintf(stderr, "LWS_CALLBACK_ADD_POLL_FD: hash table overflow\n");
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return 1;
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}
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// fprintf(stderr, "Adding fd %d at pollfd_maps[%d][%d], pollfds[%d]\n", fd, hash, pollfd_count[hash], count_pollfds);
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pollfd_maps[hash][pollfd_count[hash]].fd = fd;
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pollfd_maps[hash][pollfd_count[hash]++].index = count_pollfds;
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pollfds[count_pollfds].fd = (int)(long)user;
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pollfds[count_pollfds].events = (int)len;
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@ -148,34 +201,71 @@ static int callback_http(struct libwebsocket_context *context,
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break;
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case LWS_CALLBACK_DEL_POLL_FD:
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for (n = 0; n < count_pollfds; n++) {
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if (pollfds[n].fd != (int)(long)user)
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continue;
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/*
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* swap the end guy into our vacant slot...
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* works ok if n is the end guy
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*/
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pollfds[n] = pollfds[count_pollfds - 1];
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pollfds[count_pollfds - 1].fd = -1;
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count_pollfds--;
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break;
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hash = POLL_HASH(fd);
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n = find_poll_map_index(hash, fd);
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if (n < 0) {
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fprintf(stderr, "unable to find fd %d in poll_maps\n", fd);
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return 1;
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}
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m = pollfd_maps[hash][n].index;
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assert(pollfds[m].fd == fd);
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assert(count_pollfds);
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assert(pollfd_count[hash]);
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// fprintf(stderr, "Removing fd %d at pollfd_maps[%d][%d], pollfds[%d]\n", fd, hash, n, m);
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/*
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* swap the end guy into our vacant slot...
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* works ok if n is the end guy
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*/
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count_pollfds--;
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if (count_pollfds) {
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/* end guy... */
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hash1 = POLL_HASH(pollfds[count_pollfds].fd);
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m1 = find_poll_map_index(hash1, pollfds[count_pollfds].fd);
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/* your index has changed... */
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pollfd_maps[hash1][m1].index = m;
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pollfds[m] = pollfds[count_pollfds];
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pollfds[count_pollfds].fd = -1;
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}
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/*
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* similar trick with hashtable
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* old end guy goes into vacant slot in hash table
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*/
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pollfd_count[hash]--;
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if (pollfd_count[hash]) {
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pollfd_maps[hash][n].index = pollfd_maps[hash][pollfd_count[hash]].index;
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pollfd_maps[hash][n].fd = pollfd_maps[hash][pollfd_count[hash]].fd;
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}
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break;
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case LWS_CALLBACK_SET_MODE_POLL_FD:
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for (n = 0; n < count_pollfds; n++)
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if (pollfds[n].fd == (int)(long)user) {
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pollfds[n].events |= (int)(long)len;
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break;
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}
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n = find_pollfd_index(fd);
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if (n < 0) {
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fprintf(stderr, "unable to find fd %d\n", fd);
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return 1;
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}
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if(pollfds[n].fd != fd) {
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fprintf(stderr, "Setting fd %d, found at pollfd_index %d, actually fd %d\n", fd, n, pollfds[n].fd);
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assert(0);
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}
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pollfds[n].events |= (int)(long)len;
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break;
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case LWS_CALLBACK_CLEAR_MODE_POLL_FD:
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for (n = 0; n < count_pollfds; n++)
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if (pollfds[n].fd == (int)(long)user) {
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pollfds[n].events &= ~(int)(long)len;
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break;
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}
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n = find_pollfd_index(fd);
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if (n < 0) {
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fprintf(stderr, "unable to find fd %d\n", fd);
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return 1;
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}
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assert(pollfds[n].fd == fd);
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pollfds[n].events &= ~(int)(long)len;
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break;
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#endif
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default:
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