From owner-freebsd-bugs@freebsd.org Sat Aug 11 02:57:46 2018 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A7F4C105B488 for ; Sat, 11 Aug 2018 02:57:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 4570B88340 for ; Sat, 11 Aug 2018 02:57:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 09DEF105B487; Sat, 11 Aug 2018 02:57:46 +0000 (UTC) Delivered-To: bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id ECDC1105B486 for ; Sat, 11 Aug 2018 02:57:45 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 8F0CC8833B for ; Sat, 11 Aug 2018 02:57:45 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id DC677CAC9 for ; Sat, 11 Aug 2018 02:57:44 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w7B2viuQ003321 for ; Sat, 11 Aug 2018 02:57:44 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from bugzilla@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w7B2viYl003320 for bugs@FreeBSD.org; Sat, 11 Aug 2018 02:57:44 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: bugzilla set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230491] stat(1): Improve performance with getpwuid() and getgrgid() caching Date: Sat, 11 Aug 2018 02:57:45 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: 11.2-STABLE X-Bugzilla-Keywords: needs-qa, patch, performance X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: commit-hook@freebsd.org X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: mfc-stable10? mfc-stable11? X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Aug 2018 02:57:46 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D230491 --- Comment #12 from commit-hook@freebsd.org --- A commit references this bug: Author: cem Date: Sat Aug 11 02:56:44 UTC 2018 New revision: 337600 URL: https://svnweb.freebsd.org/changeset/base/337600 Log: stat(1): cache id->name resolution When invoked on a large list of files, it is most common for a small numb= er of uids/gids to own most of the results. Like ls(1), use pwcache(3) to avoid repeatedly looking up the same IDs. Example microbenchmark and non-scientific results: $ time (find /usr/src -type f -print0 | xargs -0 stat >/dev/null) BEFORE: 3.62s user 5.23s system 102% cpu 8.655 total 3.47s user 5.38s system 102% cpu 8.647 total AFTER: 1.23s user 1.81s system 108% cpu 2.810 total 1.43s user 1.54s system 107% cpu 2.754 total Does this microbenchmark have any real-world significance? Until a use c= ase is demonstrated otherwise, I doubt it. Ordinarily I would be resistant to optimizing pointless microbenchmarks in base utilities (e.g., recent tota= lly gratuitous changes to yes(1)). However, the pwcache(3) APIs actually simplify stat(1) logic ever so slightly compared to the raw APIs they wra= p, so I think this is at worst harmless. PR: 230491 Reported by: Thomas Hurst Discussed with: gad@ Changes: head/usr.bin/stat/stat.c --=20 You are receiving this mail because: You are the assignee for the bug.=