commit 55907da28dd933a7724935a8a4676aec1b54059d Author: Andrea Shepard <andrea@torproject.org> Date: Mon Dec 2 01:05:28 2013 -0800 Sort the scheduler's channel list by cmux comparisons --- src/or/scheduler.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 51 insertions(+), 2 deletions(-) diff --git a/src/or/scheduler.c b/src/or/scheduler.c index 1baf375..b45df3e 100644 --- a/src/or/scheduler.c +++ b/src/or/scheduler.c @@ -139,6 +139,7 @@ static time_t queue_heuristic_timestamp = 0; /* Scheduler static function declarations */ +static int scheduler_compare_channels(const void **c1_v, const void **c2_v); static void scheduler_evt_callback(evutil_socket_t fd, short events, void *arg); static int scheduler_more_work(void); @@ -180,6 +181,52 @@ scheduler_free_all(void) } } +/** + * Comparison function to use when sorting pending channels + */ + +static int +scheduler_compare_channels(const void **c1_v, const void **c2_v) +{ + channel_t *c1 = NULL, *c2 = NULL; + /* These are a workaround for -Wbad-function-cast throwing a fit */ + const circuitmux_policy_t *p1, *p2; + uintptr_t p1_i, p2_i; + + tor_assert(c1_v); + tor_assert(c2_v); + + c1 = (channel_t *)(*c1_v); + c2 = (channel_t *)(*c2_v); + + tor_assert(c1); + tor_assert(c2); + + if (c1 != c2) { + if (circuitmux_get_policy(c1->cmux) == + circuitmux_get_policy(c2->cmux)) { + /* Same cmux policy, so use the mux comparison */ + return circuitmux_compare_muxes(c1->cmux, c2->cmux); + } else { + /* + * Different policies; not important to get this edge case perfect + * because the current code never actually gives different channels + * different cmux policies anyway. Just use this arbitrary but + * definite choice. + */ + p1 = circuitmux_get_policy(c1->cmux); + p2 = circuitmux_get_policy(c2->cmux); + p1_i = (uintptr_t)p1; + p2_i = (uintptr_t)p2; + + return (p1_i < p2_i) ? -1 : 1; + } + } else { + /* c1 == c2, so always equal */ + return 0; + } +} + /* * Scheduler event callback; this should get triggered once per event loop * if any scheduling work was created during the event loop. @@ -362,9 +409,11 @@ scheduler_run(void) channels_pending = smartlist_new(); /* - * For now, just run the old scheduler on all the chans in the list, until - * we hit the high-water mark. TODO real channel priority API + * UGLY HACK: sort the list on each invocation + * + * TODO smarter data structures */ + smartlist_sort(tmp, scheduler_compare_channels); SMARTLIST_FOREACH_BEGIN(tmp, channel_t *, chan) { if (scheduler_get_queue_heuristic() <= SCHED_Q_HIGH_WATER) {