From nobody Mon Sep 06 08:08:30 2021 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 8A59A17BB956 for ; Mon, 6 Sep 2021 08:08:48 +0000 (UTC) (envelope-from jlehen@gmail.com) Received: from mail-io1-f46.google.com (mail-io1-f46.google.com [209.85.166.46]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4H31Hz3T0Zz3Jgh for ; Mon, 6 Sep 2021 08:08:47 +0000 (UTC) (envelope-from jlehen@gmail.com) Received: by mail-io1-f46.google.com with SMTP id e186so7620554iof.12 for ; Mon, 06 Sep 2021 01:08:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=ChAvvNFVIu3+5PyteIa4O3XfsWoiYLgooAIRQxrF1y4=; b=VyfDNcKtAkGvIfmCJo7djidLnhyVG7ymxSJl6apPPqjMsZuJiF+kdRtXmICCD0eWAd Akmwev0gSRmhyPzjaBigjAiXvflvF8TBd0c6RpHKI4O1UN6lmvbNs+4lx+Ref59/junS 74ox6lRcPLbRnm3RWN7IieGwo0zkuZwgITuTuiVIeAV0v7fNB4tptKjdYsxvn7xSQ0I5 kIPq5HHXQzhrfD67DrWlBRwW33USGMYKK9KBcNlIF7p/Pyo/efJLqAO5eFTlbw4bP2N5 0OlTDe4WhhVeIM8Lm/5t/WiDUe6heB3tX+LNoZ1XZPXQF3xPlV3ICJO7ETaw16wc5u4O Es6w== X-Gm-Message-State: AOAM531VQ+LEOIq/kIzpKpdPAfIRkpMWw5eqEniO5Q0NZ7XTL97kLSb6 PT2XIJ5qgQ0ZWmVVhV0R5s/YPHNMCsXN30x3wdjJLGPE6EWT/A== X-Google-Smtp-Source: ABdhPJzVpq+LmWmgRr/QWeVG/1n4956pNUXdTRfaQqE+s62kBXpkmTLf9BpDK6miyznsGcfYCs3dacqP/9AdkFHg1ds= X-Received: by 2002:a6b:7a03:: with SMTP id h3mr8656611iom.39.1630915721099; Mon, 06 Sep 2021 01:08:41 -0700 (PDT) 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 From: Jeremie Le Hen Date: Mon, 6 Sep 2021 10:08:30 +0200 Message-ID: Subject: -CURRENT compilation time To: FreeBSD Current Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4H31Hz3T0Zz3Jgh X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of jlehen@gmail.com designates 209.85.166.46 as permitted sender) smtp.mailfrom=jlehen@gmail.com X-Spamd-Result: default: False [-2.99 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:209.85.128.0/17:c]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-current@freebsd.org]; DMARC_NA(0.00)[freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000]; TO_DN_ALL(0.00)[]; NEURAL_HAM_SHORT(-0.99)[-0.995]; RCVD_IN_DNSWL_NONE(0.00)[209.85.166.46:from]; FORGED_SENDER(0.30)[jlh@freebsd.org,jlehen@gmail.com]; RWL_MAILSPIKE_POSSIBLE(0.00)[209.85.166.46:from]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:15169, ipnet:209.85.128.0/17, country:US]; FROM_NEQ_ENVFROM(0.00)[jlh@freebsd.org,jlehen@gmail.com]; FREEMAIL_ENVFROM(0.00)[gmail.com]; TO_DOM_EQ_FROM_DOM(0.00)[] X-ThisMailContainsUnwantedMimeParts: N Hey, I want to build -CURRENT again from sources. It's been a long time since I hadn't done that. I'm shocked by the compilation time. I started the whole thing on Friday night and Monday morning it's still in stage 4.2 (building libraries). Through occasional glancing at the screen over the weekend, it seems obvious to me that the compilation time is utterly dominated by LLVM. Compiling C++ seems extremely CPU heavy and this is made worse by the fact LLVM is built twice (once for build/cross tools, once for the actual world). So OK, my CPU is not the most powerful out there but it's still decent [1]. So I have a couple of questions coming to my mind: 1. Is there any optimization I could benefit from? (I'm sure there's a knob to use the existing compiler instead of building a cross-compiler.) 2. More generally, isn't this compilation time not considered as a problem for developers? This seems to terribly slow down the iteration time for people working on the build system. I wouldn't be surprised if this drove people away from working on/improving that area. [1] https://www.cpubenchmark.net/cpu.php?cpu=Intel+Core+i5-6260U+%40+1.80GHz&id=2671 Cheers, -- Jeremie Le Hen jlh@FreeBSD.org