From nobody Sat Dec 6 17:24:33 2025 X-Original-To: freebsd-current@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4dNw9D1tTdz6HpJc for ; Sat, 06 Dec 2025 17:24:48 +0000 (UTC) (envelope-from kib@freebsd.org) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4dNw9C1lGdz3PdN for ; Sat, 06 Dec 2025 17:24:47 +0000 (UTC) (envelope-from kib@freebsd.org) Authentication-Results: mx1.freebsd.org; none Received: from tom.home (kib@localhost [127.0.0.1] (may be forged)) by kib.kiev.ua (8.18.1/8.18.1) with ESMTP id 5B6HOXrF009388; Sat, 6 Dec 2025 19:24:37 +0200 (EET) (envelope-from kib@freebsd.org) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 5B6HOXrF009388 Received: (from kostik@localhost) by tom.home (8.18.1/8.18.1/Submit) id 5B6HOXc8009387; Sat, 6 Dec 2025 19:24:33 +0200 (EET) (envelope-from kib@freebsd.org) X-Authentication-Warning: tom.home: kostik set sender to kib@freebsd.org using -f Date: Sat, 6 Dec 2025 19:24:33 +0200 From: Konstantin Belousov To: Mateusz Guzik Cc: FreeBSD Current Subject: Re: performance regressions in 15.0 Message-ID: References: List-Id: Discussions about the use of FreeBSD-current List-Archive: https://lists.freebsd.org/archives/freebsd-current List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-current@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham autolearn_force=no version=4.0.2 X-Spam-Checker-Version: SpamAssassin 4.0.2 (2025-08-27) on tom.home X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Queue-Id: 4dNw9C1lGdz3PdN On Sat, Dec 06, 2025 at 11:50:08AM +0100, Mateusz Guzik wrote: > II. compilation speed > > The the real and serious problem. Both versions of the system ship the > same clang version: > FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git > llvmorg-19.1.7-0-gcd708029e0b2) > Target: x86_64-unknown-freebsd14.3 > Thread model: posix > InstalledDir: /usr/bin > > FreeBSD clang version 19.1.7 (https://github.com/llvm/llvm-project.git > llvmorg-19.1.7-0-gcd708029e0b2) > Target: x86_64-unknown-freebsd15.0 > Thread model: posix > InstalledDir: /usr/bin > > I found that compiling the will-it-scale suite about doubles in real > time needed, along with doubling time spent in userspace. > > will-it-scale needs a little bit of massaging to work, diff at the end. > > check this out (repeabale): while true; do gmake -s clean && time > gmake -s -j 8; done > > 14.3: > gmake -s -j 8 8.93s user 2.03s system 769% cpu 1.42s (1.424) total > gmake -s -j 8 9.02s user 2.16s system 757% cpu 1.48s (1.475) total > gmake -s -j 8 9.29s user 1.95s system 774% cpu 1.45s (1.450) total > gmake -s -j 8 8.97s user 2.46s system 770% cpu 1.48s (1.484) total > gmake -s -j 8 9.13s user 2.30s system 773% cpu 1.48s (1.477) total 14.3 clang/lld are probably statically linked, but I am not sure. Can you confirm this? > > 15.0: > gmake -s -j 8 19.90s user 3.02s system 773% cpu 2.96s (2.963) total > gmake -s -j 8 19.90s user 3.18s system 774% cpu 2.98s (2.979) total > gmake -s -j 8 20.24s user 2.90s system 770% cpu 3.00s (3.005) total > gmake -s -j 8 19.92s user 3.25s system 771% cpu 3.00s (3.003) total > gmake -s -j 8 20.25s user 2.95s system 772% cpu 3.01s (3.006) total But 15.0 is definitely dynamically linked. clang is enormous C++ binary with enormous amount of relocs: $ ldd /usr/bin/cc /usr/bin/cc: libprivateclang.so.19 => /usr/lib/libprivateclang.so.19 (0x27417e200000) libprivatellvm.so.19 => /usr/lib/libprivatellvm.so.19 (0x274183e00000) $ objdump -R /usr/lib/libprivateclang.so.19 | wc -l 232977 $ objdump -R /usr/lib/libprivatellvm.so.19 | wc -l 140712 > > user time *skyrocketed*