Data may have lots of overlapping mmaps. The regular insert adds at
the end and relies on a later sort. For data with overlapping mappings
the sort will happen during a subsequent maps__find or
__maps__fixup_overlap_and_insert, there's never a period where the
inserted maps buffer up and a single sort happens. To avoid back to
back sorts, maintain the sort order when fixing up and
inserting. Previously the first_ending_after search was O(log n) where
n is the size of maps, and the insert was O(1) but because of the
continuous sorting was becoming O(n*log(n)). With maintaining sort
order, the insert now becomes O(n) for a memmove.
For a perf report on a perf.data file containing overlapping mappings
the time numbers are:
Before:
real 0m5.894s
user 0m5.650s
sys 0m0.231s
After:
real 0m0.675s
user 0m0.454s
sys 0m0.196s
Signed-off-by: Ian Rogers <[email protected]>
---
tools/perf/util/maps.c | 65 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 59 insertions(+), 6 deletions(-)
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index f6b6df82f4cf..432399cbe5dd 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -735,6 +735,60 @@ static unsigned int first_ending_after(struct maps *maps, const struct map *map)
return first;
}
+static int __maps__insert_sorted(struct maps *maps, unsigned int first_after_index,
+ struct map *new1, struct map *new2)
+{
+ struct map **maps_by_address = maps__maps_by_address(maps);
+ struct map **maps_by_name = maps__maps_by_name(maps);
+ unsigned int nr_maps = maps__nr_maps(maps);
+ unsigned int nr_allocate = RC_CHK_ACCESS(maps)->nr_maps_allocated;
+ unsigned int to_add = new2 ? 2 : 1;
+
+ assert(maps__maps_by_address_sorted(maps));
+ assert(first_after_index == nr_maps ||
+ map__end(new1) <= map__start(maps_by_address[first_after_index]));
+ assert(!new2 || map__end(new1) <= map__start(new2));
+ assert(first_after_index == nr_maps || !new2 ||
+ map__end(new2) <= map__start(maps_by_address[first_after_index]));
+
+ if (nr_maps + to_add > nr_allocate) {
+ nr_allocate = !nr_allocate ? 32 : nr_allocate * 2;
+
+ maps_by_address = realloc(maps_by_address, nr_allocate * sizeof(new1));
+ if (!maps_by_address)
+ return -ENOMEM;
+
+ maps__set_maps_by_address(maps, maps_by_address);
+ if (maps_by_name) {
+ maps_by_name = realloc(maps_by_name, nr_allocate * sizeof(new1));
+ if (!maps_by_name) {
+ /*
+ * If by name fails, just disable by name and it will
+ * recompute next time it is required.
+ */
+ __maps__free_maps_by_name(maps);
+ }
+ maps__set_maps_by_name(maps, maps_by_name);
+ }
+ RC_CHK_ACCESS(maps)->nr_maps_allocated = nr_allocate;
+ }
+ memmove(&maps_by_address[first_after_index+to_add],
+ &maps_by_address[first_after_index],
+ (nr_maps - first_after_index) * sizeof(new1));
+ maps_by_address[first_after_index] = map__get(new1);
+ if (maps_by_name)
+ maps_by_name[nr_maps] = map__get(new1);
+ if (new2) {
+ maps_by_address[first_after_index + 1] = map__get(new2);
+ if (maps_by_name)
+ maps_by_name[nr_maps + 1] = map__get(new2);
+ }
+ RC_CHK_ACCESS(maps)->nr_maps = nr_maps + to_add;
+ maps__set_maps_by_name_sorted(maps, false);
+ check_invariants(maps);
+ return 0;
+}
+
/*
* Adds new to maps, if new overlaps existing entries then the existing maps are
* adjusted or removed so that new fits without overlapping any entries.
@@ -743,6 +797,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
{
int err = 0;
FILE *fp = debug_file();
+ unsigned int i;
if (!maps__maps_by_address_sorted(maps))
__maps__sort_by_address(maps);
@@ -751,7 +806,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
* Iterate through entries where the end of the existing entry is
* greater-than the new map's start.
*/
- for (unsigned int i = first_ending_after(maps, new); i < maps__nr_maps(maps); ) {
+ for (i = first_ending_after(maps, new); i < maps__nr_maps(maps); ) {
struct map **maps_by_address = maps__maps_by_address(maps);
struct map *pos = maps_by_address[i];
struct map *before = NULL, *after = NULL;
@@ -824,9 +879,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
* 'pos' mapping and therefore there are no
* later mappings.
*/
- err = __maps__insert(maps, new);
- if (!err)
- err = __maps__insert(maps, after);
+ err = __maps__insert_sorted(maps, i, new, after);
map__put(after);
check_invariants(maps);
return err;
@@ -839,7 +892,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
*/
map__put(maps_by_address[i]);
maps_by_address[i] = map__get(new);
- err = __maps__insert(maps, after);
+ err = __maps__insert_sorted(maps, i + 1, after, NULL);
map__put(after);
check_invariants(maps);
return err;
@@ -869,7 +922,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
}
}
/* Add the map. */
- err = __maps__insert(maps, new);
+ err = __maps__insert_sorted(maps, i, new, NULL);
out_err:
return err;
}
--
2.45.0.rc1.225.g2a3ae87e7f-goog