From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.200 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792622383; b=FEZr0OP5fvGRg0p0HfecvAz45TBXx1WJVYGooQtfmT/FzLd1C/sDsQbUtGI9YAZVLSdH rF26rH4d5g4FujdMYElniKIRO2OBu3JXNKNd2gro4P5yRgQ4JjFCndPvhB3ETTLg9kaSA MM/wWOhYlUla+NHZUBo09Oor1li9y6hI8YPgMaP24PbkiHvrYXznOn/AuevnfcJaazjWn W2UcTQC8sDRUp9V4Gp6ghWN1n3KqRK9YgJplAbryE+asr5sgOqoRGRdz6bDgdoWbOQOtB R/ynhbagyIRj59DQMFd3hEhC3XSbWL8b4aVnCs6dcOliCSAjkw2dnzkKBOCWISUlSsA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792622383; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Received:Date:In-Reply-To: Mime-Version:References:X-Mailer:Message-ID:Subject:From:To:Cc: Content-Type; bh=tais/mmpVOY0wxTi4olaaP5GHUDvOJakQ1sADr4zkQs=; b=zFhZQyASFuuBW0CwyKor9EfrWkSYUw6M6YqbluxJSU0Zwmv5DnJAz7guUxkapKTx9xvL 7eU2zJjmd5VptDvgCy9Y7M0n8jr6qNtJJvX70biq6D4PtmxlKkRgiAxaIZdlr3x+6ZTsG za9Gs2b4a3P2fHGZZPd1TQHNkve7623oe6mMl5hhm/vsERpKUtwieTahdiKXW6T1mbxH7 IVBSaB+5LdUtqf59MOAwYcUxnVyfRWfBKmgYpRZGHoZsgAaTxd5A6vByCehDbKwqO5KhS RhgTBv0mBz6mlOEGpjaN0J4U1ptZgDCmV897jUSCY5GaqDX0M/2Z3Aq3Q+vcKNWBe1A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20251104 header.b=O5RP0gTS; arc=none smtp.remote-ip=74.125.82.200 Received: from mail-dy1-f200.google.com (mail-dy1-f200.google.com [74.125.82.200]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1E78E606A322 for ; Wed, 21 Oct 2026 22:39:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1E78E606A322 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20251104 header.b=O5RP0gTS Received: by mail-dy1-f200.google.com with SMTP id 5a478bee46e88-36637676140so2076825eec.0 for ; Wed, 21 Oct 2026 15:39:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1792622381; x=1793227181; darn=lists.linux.dev; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=tais/mmpVOY0wxTi4olaaP5GHUDvOJakQ1sADr4zkQs=; b=O5RP0gTSl8uE09IYR8/Y0JoKpyH86JO9b9d9Yv44pyjVEBSEa1ro3wPga/SlBwF01Q l2hlk/SmVmANovprNMny80GXXq59eKrgbBExuiEEuh/ZHkbvKStZgl4e25SmEdrBtugV XDKRq6xCahuJk7yFJKRgzFe3uVAbeKg/44TDus7zzTP+TJ/WrppXIF2NsYm3daw5ZGzp gKPheve1ntLPbPmY8ZU0nRZ0t8387nnD21UVY4xFPoIE6i6Tfb1qNp0zfIk2QJR3Tbfz oIDChOxFgH6uO7kzHS7SMbGZoKbK450C075lm1CYripr3g1KZ77tSQedna4Dq3FXEUtH tfjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792622381; x=1793227181; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=tais/mmpVOY0wxTi4olaaP5GHUDvOJakQ1sADr4zkQs=; b=GKDlObdGRJPj1yPxC/s1l4ozMi97K58hS1xewd/JJRKZbfl44udqJyikey0vA+Fn1K 6u25KP/s86FudF6JLAg9QEI4aw+KM1GMYQUBuK4dAALaVwEZIt3pAK7TkHA3k6yGel96 uVFFQWkHtdKoX0niWuAHlyfqIrHdIRgo0fQSymKjyROcJW813gSz5bV3ncULD9ywKa8U smy2nNtH65sDMYuU957OJIqEwC6xeu/JkXSGXU3CKh4URE4YVo5gNSJkA2BQfHXP9GGE FWUZwDL+aWXL5zdgP7xNxhJf+uwUSktkxYknkBzaxGOLSp6tTrWWEm/ciqzqJ9sqY3og gWoQ== X-Forwarded-Encrypted: i=1; AKwUvBzUfOOIWiUIpI8a572WJe4cB1Q6ldbOjG8L95RcQ1GBLAG1u/5v6y5H/sgunDj/VAiHTU2P@lists.linux.dev X-Gm-Message-State: AFq9FYLTkesi9XmfpIpqK6JJcY1+0ijs8t0gKTqk151ru5geNNzzTT7Z 3g0WL2RLL3/G667cpNDbV4/WypIop+kZj872VvCzTEn3PBVJ+uW/40rvxSKI4KYRBV3r21J9/wS 3cT7l8a4N6A== X-Received: from dyuq24.prod.google.com ([2002:a05:693c:66d8:b0:366:847a:68e8]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:693c:42c3:b0:360:1637:404 with SMTP id 5a478bee46e88-3674f1164a4mr4452520eec.33.1792622380820; Wed, 21 Oct 2026 15:39:40 -0700 (PDT) Date: Wed, 21 Oct 2026 15:38:58 -0700 In-Reply-To: <20261021223905.715051-1-irogers@google.com> X-Mailing-List: llvm@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 References: <20261021171044.155240-1-irogers@google.com> <20261021223905.715051-1-irogers@google.com> X-Mailer: git-send-email 2.56.0.218.g1ec904b173-goog Message-ID: <20261021223905.715051-11-irogers@google.com> Subject: [PATCH v7 10/17] perf dsos: Use read lock fast path in dsos__findnew_id() From: Ian Rogers To: irogers@google.com, acme@kernel.org, elver@google.com, namhyung@kernel.org Cc: adrian.hunter@intel.com, james.clark@linaro.org, jolsa@kernel.org, justinstitt@google.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, ljs@kernel.org, llvm@lists.linux.dev, mingo@redhat.com, morbo@google.com, nathan@kernel.org, ndesaulniers@google.com, peterz@infradead.org Content-Type: text/plain; charset="UTF-8" In dsos__findnew_id(), try finding the DSO under the read lock first and only acquire the write lock when a new DSO must be inserted or an existing DSO needs its ID updated (checked via dso__needs_improve_id()). Signed-off-by: Ian Rogers --- tools/perf/util/dso.c | 16 +++++++++++++++- tools/perf/util/dso.h | 1 + tools/perf/util/dsos.c | 10 ++++++++++ 3 files changed, 26 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c index f0e02062c09c..4dc518f7cb7d 100644 --- a/tools/perf/util/dso.c +++ b/tools/perf/util/dso.c @@ -1685,6 +1685,18 @@ const struct dso_id dso_id_empty = { } }; +bool dso__needs_improve_id(const struct dso *dso, const struct dso_id *id) +{ + const struct dso_id *dso_id = dso__id_const(dso); + + if (!id) + return false; + + return (id->mmap2_valid && !dso_id->mmap2_valid) || + (id->mmap2_ino_generation_valid && !dso_id->mmap2_ino_generation_valid) || + (build_id__is_defined(&id->build_id) && !build_id__is_defined(&dso_id->build_id)); +} + void __dso__improve_id(struct dso *dso, const struct dso_id *id) { struct dsos *dsos = dso__dsos(dso); @@ -1692,6 +1704,8 @@ void __dso__improve_id(struct dso *dso, const struct dso_id *id) bool changed = false; /* dsos write lock held by caller. */ + if (!id) + return; if (id->mmap2_valid && !dso_id->mmap2_valid) { dso_id->maj = id->maj; @@ -1715,7 +1729,7 @@ void __dso__improve_id(struct dso *dso, const struct dso_id *id) int dso_id__cmp(const struct dso_id *a, const struct dso_id *b) { - if (a == &dso_id_empty || b == &dso_id_empty) { + if (!a || !b || a == &dso_id_empty || b == &dso_id_empty) { /* There is no valid data to compare so the comparison always returns identical. */ return 0; } diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h index 9f026ccb0eb6..394960cd2004 100644 --- a/tools/perf/util/dso.h +++ b/tools/perf/util/dso.h @@ -802,6 +802,7 @@ void dso__delete(struct dso *dso); int dso__cmp_id(struct dso *a, struct dso *b); void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated); void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated); +bool dso__needs_improve_id(const struct dso *dso, const struct dso_id *id); void __dso__improve_id(struct dso *dso, const struct dso_id *id); int dso__name_len(const struct dso *dso); diff --git a/tools/perf/util/dsos.c b/tools/perf/util/dsos.c index 40267d3a725d..b5c8086941d5 100644 --- a/tools/perf/util/dsos.c +++ b/tools/perf/util/dsos.c @@ -348,6 +348,16 @@ static struct dso *__dsos__findnew_id(struct dsos *dsos, const char *name, const struct dso *dsos__findnew_id(struct dsos *dsos, const char *name, const struct dso_id *id) { struct dso *dso; + + down_read(&dsos->lock); + dso = __dsos__find_id(dsos, name, id, false, /*write_locked=*/false); + if (dso && !dso__needs_improve_id(dso, id)) { + up_read(&dsos->lock); + return dso; + } + up_read(&dsos->lock); + dso__put(dso); + down_write(&dsos->lock); dso = __dsos__findnew_id(dsos, name, id); up_write(&dsos->lock); -- 2.56.0.218.g1ec904b173-goog