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[23.128.96.18]) by mx.google.com with ESMTP id t24si466150ejd.39.2020.10.23.02.26.36; Fri, 23 Oct 2020 02:26:59 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S461420AbgJWJYs (ORCPT + 99 others); Fri, 23 Oct 2020 05:24:48 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:36077 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S461413AbgJWJYs (ORCPT ); Fri, 23 Oct 2020 05:24:48 -0400 Received: by mail-ot1-f65.google.com with SMTP id 32so735998otm.3; Fri, 23 Oct 2020 02:24:47 -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:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Zc+AeQKYu0eA1NCCr9Ea0RhGk/czUMV0vr6kVFJGHw0=; b=svL8bMrhDiYdFU+nFRtfqmOTeNEsuLToWpA+nHPR5eeAcE7vAK9E0lqS+vuiZ6CrWN PBQnXJ1Ri/xnY6yWeDoDwod69OLYqXUn4oD+B7/fozdJydzRwv+Zc/21rTv/pmxgvuJO NE3sE3Qtew4RgCkawyh0mwvmHIqGwUTdmFJDMnPqYnFHHV/6dnTEr6Y3KyQuqk2bX9yG x7al8CTEqWpgv4ghMJABLurkaPz1HG1CFbmeezoY5QzmFB6hvFaMkAAkxyDRHQFKcQx4 +dhlY7GLWB5uBcsb1GRz/M0rStunz4sVTfb26bvaifJyanZEaB6+kr43EcHMY3khCPx1 a1SQ== X-Gm-Message-State: AOAM533HcoD//sSkCHkQJXswjFpctjlDUp88eJeC1UFKkz9VVlgu3ZAT sKqT5MxLYtDs9UKuhQRUhfo0eRav94ezvAFWrio= X-Received: by 2002:a9d:3b76:: with SMTP id z109mr904469otb.250.1603445087314; Fri, 23 Oct 2020 02:24:47 -0700 (PDT) MIME-Version: 1.0 References: <20201008154651.1901126-1-arnd@arndb.de> <20201008154651.1901126-14-arnd@arndb.de> In-Reply-To: From: Geert Uytterhoeven Date: Fri, 23 Oct 2020 11:24:36 +0200 Message-ID: Subject: Re: [RFC 13/13] m68k: mac: convert to generic clockevent To: Arnd Bergmann Cc: Finn Thain , "linux-kernel@vger.kernel.org" , Russell King , Tony Luck , Fenghua Yu , Greg Ungerer , Philip Blundell , Joshua Thompson , Sam Creasey , "James E.J. Bottomley" , Helge Deller , Thomas Gleixner , Daniel Lezcano , John Stultz , Stephen Boyd , Linus Walleij , "linux-ia64@vger.kernel.org" , Parisc List , linux-m68k , Linux ARM Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On Fri, Oct 23, 2020 at 9:52 AM Arnd Bergmann wrote: > On Sun, Oct 18, 2020 at 2:55 AM Finn Thain wrote: > > On Thu, 15 Oct 2020, Arnd Bergmann wrote: > > > On Thu, Oct 15, 2020 at 3:19 AM Finn Thain wrote: > > > > On Sat, 10 Oct 2020, Arnd Bergmann wrote: > > > > That configuration still produces the same 5 KiB of bloat. I see that > > kernel/time/Kconfig has this -- > > > > # Core internal switch. Selected by NO_HZ_COMMON / HIGH_RES_TIMERS. This is > > # only related to the tick functionality. Oneshot clockevent devices > > # are supported independent of this. > > config TICK_ONESHOT > > bool > > > > But my question was really about both kinds of dead code (oneshot device > > support and oneshot tick support). Anyway, after playing with the code for > > a bit I don't see any easy way to reduce the growth in text size. > > Did you look more deeply into where those 5KB are? Is this just > the code in kernel/time/{clockevents,tick-common}.c and the > added platform specific bits, or is there something more? > I suppose the sysfs interface and the clockevents_update_freq() > logic are not really needed on m68k, but it wouldn't make much > sense to split those out either. > > How does the 5KB bloat compare to the average bloat we get > from one release to the next? Geert has been collecting statistics > for this. It would be a fair share of the typical increase of ca. 30 KiB per kernel release. Still, it would be lost in the noise of the increase for v5.10-rc1: add/remove: 1200/455 grow/shrink: 1419/821 up/down: 468970/-93714 (375256) Function old new delta _printk_rb_static_infos - 180224 +180224 write_buf 8192 32768 +24576 _printk_rb_static_descs - 24576 +24576 HUF_decompress4X4_usingDTable_internal - 5664 +5664 HUF_decompress4X2_usingDTable_internal - 5006 +5006 __ext4_ioctl - 4774 +4774 sock_ops_convert_ctx_access 3840 8462 +4622 ZSTD_decompressSequences - 3100 +3100 > > > The arm/rpc timer seems to be roughly in the same category as most of > > > the m68k ones or the i8253 counter on a PC. It's possible that some of > > > them could use the same logic as drivers/clocksource/i8253.o as long as > > > there is any hardware oneshot mode. > > > > There appear to be 15 platforms in that category. 4 have no clocksource > > besides the jiffies clocksource, meaning there's no practical alternative > > to using a periodic tick, like you did in your RFC patch: > > > > arch/m68k/apollo/config.c > > arch/m68k/q40/q40ints.c > > arch/m68k/sun3/sun3ints.c > > arch/m68k/sun3x/time.c > > Do any of these have users? I'm fairly sure sun3x has never worked in mainline, > sun3 seems to still need the same few patches it did 20 years ago. I > couldn't find > much about Linux on Apollo or q40, the information on the web for either > of them seems to all be for linux-2.4 kernels. They probably don't have any users. AFAIK, the only users are the usual triumvirate of amiga/atari/mac (and perhaps the fleet of VME boards in the Australian navy? ;) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds