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=1794591624; b=heEtEYYuIXvUX87HKl9LJnyM9xbDalxVeNzlOuA9f8/L2eH9RgzYLi/kxWPlHktDYntd b4235Y9erLT0h5OZBuNn/GBw6j3GLp9G7V+l//0aTYdE1WhurJp1rVQi9IJp2yqY9xijz 5YO810309hyBpXOo1POwfmE11C67/45ITH9iXDa9W1nnftoN0qZUCKG2gFzLDeqdnaNjI /3pPZaoli1gEYsLeYN93+tGePvzHohkusyoaLZ9BG+IUz2XKyXBkY2EmD/EDz7t17vzhJ oO3azr/LcOfSM/i9Xxjs/MZBe6Qng8YNdY/csCeDuv7yXuyv598LvuBZsGQ6skK4tOQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591624; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=LBnOT+pYNjKtQCvUKDuEfxrT7ZoQnJHrgCpH8VkBawk=; b=NCtpAqjkS8jmVmETTqZATHJqpEp8gCUzTAk8xWH/Yl2W8+dApq11XuHdwf/VsoNVBD3g uvSuSL/PwYtnnbAJUTtMiIL34QlFMxaQmvdtWW34hsQlzkj6bXC8og6k6qkjyVes3Ma+C oPyiW77HzC4KkH3/jSsRYYRo9Eee00FOyKuVkbSfyWwdEFff747J1zprSIcxy608oBT8d ujzuwefCeGWyOP4uUVDj7upI18Pcce87YgZJz2R3J6ZRjLprIVl5jsBqYilBeHUlURBhi 4RFvhKAxWmrMj+dR0GI6w8bdRln2X86CEZ2MvEDzX7nT/jI+KgTAVocMnnZI25DWb3Q== 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=bfElTf3W; 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 9C0A2606B478 for ; Fri, 13 Nov 2026 17:40:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=bfElTf3W Received: by smtp.kernel.org (Postfix) with ESMTPSA id 462801F000C4; Fri, 13 Nov 2026 17:40:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794591624; bh=LBnOT+pYNjKtQCvUKDuEfxrT7ZoQnJHrgCpH8VkBawk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=bfElTf3WieD70t7cceVaQjkojFh9rLSDMTUdrhx+7li1u0IZZnLM/ccfppfuchr5D SHGtxsMWMASQ7bSrVzIcmiBsztXeK0P3hqnMXv60BcwooqARe7E3SuX1itnlYMYBLR 9jxDI021fpYbt8B6ByzsKkJFR8hLW18bJomVWqMtFk/GmhfiSu+ikTQKwOqCnqo+Pm UFCewMm3TLDTMHfD2N+iGE+galzur3aIil9jczWPpiAQ6BNPgAZA6O/kfbRLYQWmi7 1X4lNvRKRNObJOKoyl+JqFM0XA+Zo3O68jUGegGSjzw5gOLNheDhOMWyCcK79A4767 Dca50eLP/einw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 18/23] perf symbol: Switch backing storage from rbtree to struct symbols array Reply-To: sashiko-reviews@lists.linux.dev To: "Ian Rogers" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261113171734.2188066-19-irogers@google.com> References: <20261110220803.2503416-1-irogers@google.com> <20261113171734.2188066-1-irogers@google.com> <20261113171734.2188066-19-irogers@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 13 Nov 2026 17:40:23 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Previously, DSO symbols were stored in an unprotected rb_root_cached > with a 24-byte struct rb_node embedded inside every struct symbol. That > design had three drawbacks: > 1. Embedding struct rb_node (3 pointers, 24 bytes on 64-bit) accounted > for nearly 40% of struct symbol's fixed header size and scattered > symbol lookups across non-contiguous heap nodes. > 2. Unlike struct dsos and struct maps, the symbol rbtree had no lock > protecting concurrent lookups, sorting, and insertions. > 3. Deduplicating symbols, splitting kallsyms, and trimming excess symbol > container capacity under memory pressure benefit from operating on a > compact array under a lock. >=20 > Replace struct rb_node in struct symbol with a locked, lazily-sorted > pointer array in struct symbols, matching the design of struct dsos and > struct maps: > [ ... ] > After (libLLVM.so.21.1, -22.3% load, -8.1% memory): > Average DSO load + sort: 61.074 msec (+- 0.236 msec) > Average DSO memory usage: 8755 KB (+- 1 KB) >=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=3D18