From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794591021; b=nmUBnVdM6CLqZX3WGhJNbcmoV7u6jtSfZ3c5f8A1dEMQoJolZVcxTRjoHKNveUIretGp gELwHGy4MpDv5S3ODWmjWYfdV8j5rsqllgWWwN7P3VYM9D8H6BIat619dZJqX2v/33V1i OwgJtCtQTp/E9ym4nr9DwXDCzXbwX5if5Vz3uCTkwRur94Zn9sFH0Yzah1qomCf732K3A RLBJ/AEW8pYYfjVrJpEFKoFmMoSwIl3eroXke88gMibuqjLp91aRqDYKurwBH+aJKemRf leA/0SFWg7BlRpHjZmgzTgZA5LTcfSirMN9B+91o1VUV6oYo9Ml9E29wivUUGmeMhQA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591021; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=Mi87GUQwa7rUO93HI4XvnWm7gTkVguhfaVxDY6JVtVA=; b=kSD8d4iQBQq3iuO6apQfFChddjY+MXMknaF9sUi/AIGLkJ3QjcH+cahHhDggXzC5+6uk yp6i7QrIpdSyeYkNp4KkBdGTJue4mQn0mIIDH2rCCbRDXJhcDki9FHPxDM3pIcrIwK/fw 2ren/cJ4ldqai0hrBNLGKU0Sia3XuzQZTLIal1wfn5wrFj49FqhLN1tdVqE7iTqOMNlYc lVvzDlE1lWXkzqEpPUpg56+kQ6/FF4tLxBZGmrASOYGPBf14ipus0/AQlTG8a7CaWlAse m0HZ3It72s6ETQjb0TdDpcHxU0p+VB9qx8Lkd/eAtEC+aVe0VDYORACSOOOYWwxPSkA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="Ct6pAf9/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A3DE6070F3C for ; Fri, 13 Nov 2026 17:30:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Ct6pAf9/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id E403F1F000C8; Fri, 13 Nov 2026 17:30:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794591021; bh=Mi87GUQwa7rUO93HI4XvnWm7gTkVguhfaVxDY6JVtVA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Ct6pAf9/D2goFGpTyh+FC7+WHuRq3/sCi6QcYtZ9LxERAZPBjx4ZP5P85oBVAjczY nrp0/r38i5XKvOxIgPG2skksURHEe2i/zvjOEOoSXJT4+e7QP3KZPrwOh8IGY3o7Rr bwLmKMiPU8TbIkgViug7P9dvA6Y48Hi2A7y1NRr6ly4dO1pAm/zslhjrLKU7RKoqHq tweR5L15l+tRDd/LinRxqaFpZBnl2+4YrzedgNgHplWfPKuNVp1V//LpHtVOe/6hLt aV6QUz0P1EvdobV50RWbnw1gkazqeBjdpzAeqnr6mBmAFLOoPNg1DrEM5spg0plW1S CRuuRHx304eIA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 15/23] perf symbol-elf: Cache ELF program/section headers and defer symbol name lookup Reply-To: sashiko-reviews@lists.linux.dev To: "Ian Rogers" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261113171734.2188066-16-irogers@google.com> References: <20261110220803.2503416-1-irogers@google.com> <20261113171734.2188066-1-irogers@google.com> <20261113171734.2188066-16-irogers@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 13 Nov 2026 17:30:20 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Profiling dso__load_sym_internal() on large binaries showed significant > time spent in repeated libelf section and program header lookups > (elf_section_by_idx() and elf_read_program_header()) for each symbol and > in resolving elf_sym__name() before filtering out non-symbol and > non-allocated entries. >=20 > Speed up ELF symbol table loading in dso__load_sym_internal(): >=20 > - Pre-load PT_LOAD program headers into struct elf_phdr_cache and cache > per-section metadata in a 64-entry direct-mapped table in > dso__load_sym_internal() to avoid repeated libelf section and program > header lookups during symbol iteration. > - Defer elf_sym__name() lookup until after non-allocated and non-symbol > entries have been filtered out. >=20 > [ ... ] > Average DSO load + sort: 22.433 msec (+- 0.260 msec) > After (libLLVM.so.21.1, --no-demangle, -14.8%): > Average DSO load + sort: 19.122 msec (+- 0.226 msec) >=20 > Signed-off-by: Ian Rogers Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261113171734.2188= 066-1-irogers@google.com?part=3D15