linux-kernel - [PATCH v4 49/53] perf dsos: Switch hand code to bsearch

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Message-Id: <20231102175735.2272696-50-irogers@google.com>
Date:   Thu,  2 Nov 2023 10:57:31 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Nick Terrell <terrelln@...com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        Huacai Chen <chenhuacai@...nel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Vincent Whitchurch <vincent.whitchurch@...s.com>,
        "Steinar H. Gunderson" <sesse@...gle.com>,
        Liam Howlett <liam.howlett@...cle.com>,
        Miguel Ojeda <ojeda@...nel.org>,
        Colin Ian King <colin.i.king@...il.com>,
        Dmitrii Dolgov <9erthalion6@...il.com>,
        Yang Jihong <yangjihong1@...wei.com>,
        Ming Wang <wangming01@...ngson.cn>,
        James Clark <james.clark@....com>,
        K Prateek Nayak <kprateek.nayak@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        Leo Yan <leo.yan@...aro.org>,
        Ravi Bangoria <ravi.bangoria@....com>,
        German Gomez <german.gomez@....com>,
        Changbin Du <changbin.du@...wei.com>,
        Paolo Bonzini <pbonzini@...hat.com>, Li Dong <lidong@...o.com>,
        Sandipan Das <sandipan.das@....com>,
        liuwenyu <liuwenyu7@...wei.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org
Subject: [PATCH v4 49/53] perf dsos: Switch hand code to bsearch

Switch to using the bsearch library function rather than having a hand
written binary search. Const-ify some static functions to avoid
compiler warnings.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/dsos.c | 46 +++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c
index e4110438841b..23c3fe4f2abb 100644
--- a/tools/perf/util/dsos.c
+++ b/tools/perf/util/dsos.c
@@ -107,13 +107,15 @@ bool dsos__read_build_ids(struct dsos *dsos, bool with_hits)
 	return args.have_build_id;
 }
 
-static int __dso__cmp_long_name(const char *long_name, struct dso_id *id, struct dso *b)
+static int __dso__cmp_long_name(const char *long_name, const struct dso_id *id,
+				const struct dso *b)
 {
 	int rc = strcmp(long_name, b->long_name);
 	return rc ?: dso_id__cmp(id, &b->id);
 }
 
-static int __dso__cmp_short_name(const char *short_name, struct dso_id *id, struct dso *b)
+static int __dso__cmp_short_name(const char *short_name, const struct dso_id *id,
+				 const struct dso *b)
 {
 	int rc = strcmp(short_name, b->short_name);
 	return rc ?: dso_id__cmp(id, &b->id);
@@ -133,6 +135,19 @@ static int dsos__cmp_long_name_id_short_name(const void *va, const void *vb)
 	return rc;
 }
 
+struct dsos__key {
+	const char *long_name;
+	const struct dso_id *id;
+};
+
+static int dsos__cmp_key_long_name_id(const void *vkey, const void *vdso)
+{
+	const struct dsos__key *key = vkey;
+	const struct dso *dso = *((const struct dso **)vdso);
+
+	return __dso__cmp_long_name(key->long_name, key->id, dso);
+}
+
 /*
  * Find a matching entry and/or link current entry to RB tree.
  * Either one of the dso or name parameter must be non-NULL or the
@@ -143,7 +158,11 @@ static struct dso *__dsos__find_by_longname_id(struct dsos *dsos,
 					       struct dso_id *id,
 					       bool write_locked)
 {
-	int low = 0, high = dsos->cnt - 1;
+	struct dsos__key key = {
+		.long_name = name,
+		.id = id,
+	};
+	struct dso **res;
 
 	if (!dsos->sorted) {
 		if (!write_locked) {
@@ -162,23 +181,12 @@ static struct dso *__dsos__find_by_longname_id(struct dsos *dsos,
 		dsos->sorted = true;
 	}
 
-	/*
-	 * Find node with the matching name
-	 */
-	while (low <= high) {
-		int mid = (low + high) / 2;
-		struct dso *this = dsos->dsos[mid];
-		int rc = __dso__cmp_long_name(name, id, this);
+	res = bsearch(&key, dsos->dsos, dsos->cnt, sizeof(struct dso *),
+		      dsos__cmp_key_long_name_id);
+	if (!res)
+		return NULL;
 
-		if (rc == 0) {
-			return dso__get(this);	/* Find matching dso */
-		}
-		if (rc < 0)
-			high = mid - 1;
-		else
-			low = mid + 1;
-	}
-	return NULL;
+	return dso__get(*res);
 }
 
 int __dsos__add(struct dsos *dsos, struct dso *dso)
-- 
2.42.0.869.gea05f2083d-goog