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sd-event: don't provide priority stability

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Currently, we guarantee that if two event-sources with the same priority
fire at the same time, they're always dispatched in the same order. While
this might sound nice in theory, there's is little benefit in providing
stability on that level. We have no control over the order the events are
reported, hence, we cannot guarantee that we get notified about both at
the same time.

By dropping the stability guarantee, we loose roughly 10% Heap swaps in
the prioq on a desktop cold-boot. Krzysztof Kotlenga even reported up to
20% on his tests. This sounds worth optimizing, so drop the stability
guarantee.
This commit is contained in:
David Herrmann 2015-09-29 20:56:17 +02:00
parent 8a9d23e446
commit 6fe869c251
1 changed files with 0 additions and 30 deletions
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30
src/libsystemd/sd-event/sd-event.c
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@ -242,12 +242,6 @@ static int pending_prioq_compare(const void *a, const void *b) {
if (x->pending_iteration > y->pending_iteration)
return 1;
/* Stability for the rest */
if (x < y)
return -1;
if (x > y)
return 1;
return 0;
}
@ -277,12 +271,6 @@ static int prepare_prioq_compare(const void *a, const void *b) {
if (x->priority > y->priority)
return 1;
/* Stability for the rest */
if (x < y)
return -1;
if (x > y)
return 1;
return 0;
}
@ -310,12 +298,6 @@ static int earliest_time_prioq_compare(const void *a, const void *b) {
if (x->time.next > y->time.next)
return 1;
/* Stability for the rest */
if (x < y)
return -1;
if (x > y)
return 1;
return 0;
}
@ -343,12 +325,6 @@ static int latest_time_prioq_compare(const void *a, const void *b) {
if (x->time.next + x->time.accuracy > y->time.next + y->time.accuracy)
return 1;
/* Stability for the rest */
if (x < y)
return -1;
if (x > y)
return 1;
return 0;
}
@ -370,12 +346,6 @@ static int exit_prioq_compare(const void *a, const void *b) {
if (x->priority > y->priority)
return 1;
/* Stability for the rest */
if (x < y)
return -1;
if (x > y)
return 1;
return 0;
}