Commit 7b2450bb authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim
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perf dsos: When adding a dso into sorted dsos maintain the sort order 



dsos__add would add at the end of the dso array possibly requiring a
later find to re-sort the array. Patterns of find then add were
becoming O(n*log n) due to the sorts. Change the add routine to be
O(n) rather than O(1) but to maintain the sorted-ness of the dsos
array so that later finds don't need the O(n*log n) sort.

Fixes: 3f4ac23a ("perf dsos: Switch backing storage to array from rbtree/list")
Reported-by: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Cc: Steinar Gunderson <sesse@google.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Matt Fleming <matt@readmodwrite.com>
Link: https://lore.kernel.org/r/20240703172117.810918-3-irogers@google.com


Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent 88076e46

tools/perf/util/dsos.c

+21 −5
Original line number Diff line number Diff line
@@ -203,11 +203,27 @@ int __dsos__add(struct dsos *dsos, struct dso *dso) 
		dsos->dsos = temp;

		dsos->allocated = to_allocate;

	}

	if (!dsos->sorted) {

		dsos->dsos[dsos->cnt++] = dso__get(dso);

	if (dsos->cnt >= 2 && dsos->sorted) {

		dsos->sorted = dsos__cmp_long_name_id_short_name(&dsos->dsos[dsos->cnt - 2],

								 &dsos->dsos[dsos->cnt - 1])

			<= 0;

	} else {

		int low = 0, high = dsos->cnt - 1;

		int insert = dsos->cnt; /* Default to inserting at the end. */



		while (low <= high) {

			int mid = low + (high - low) / 2;

			int cmp = dsos__cmp_long_name_id_short_name(&dsos->dsos[mid], &dso);



			if (cmp < 0) {

				low = mid + 1;

			} else {

				high = mid - 1;

				insert = mid;

			}

		}

		memmove(&dsos->dsos[insert + 1], &dsos->dsos[insert],

			(dsos->cnt - insert) * sizeof(struct dso *));

		dsos->cnt++;

		dsos->dsos[insert] = dso__get(dso);

	}

	dso__set_dsos(dso, dsos);

	return 0;