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perf maps: Add/use a sorted insert for fixup overlap and insert

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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 <irogers@google.com>
Reviewed-by: James Clark <james.clark@arm.com>
Cc: Steinar H . Gunderson <sesse@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240521165109.708593-4-irogers@google.com
This commit is contained in:
Ian Rogers 2024-05-21 09:51:09 -07:00 committed by Namhyung Kim
parent aeefb04393
commit d2307fd4f9
1 changed files with 59 additions and 6 deletions
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65
tools/perf/util/maps.c
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@ -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;
}