linux-kernel - Re: [RFC 13/13] m68k: mac: convert to generic clockevent

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Date:   Sun, 25 Oct 2020 13:45:52 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Arnd Bergmann <arnd@...nel.org>
Cc:     Finn Thain <fthain@...egraphics.com.au>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Russell King <linux@...linux.org.uk>,
        Tony Luck <tony.luck@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Greg Ungerer <gerg@...ux-m68k.org>,
        Philip Blundell <philb@....org>,
        Joshua Thompson <funaho@...ai.org>,
        Sam Creasey <sammy@...my.net>,
        "James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
        Helge Deller <deller@....de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        John Stultz <john.stultz@...aro.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        "linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
        Parisc List <linux-parisc@...r.kernel.org>,
        linux-m68k <linux-m68k@...ts.linux-m68k.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RFC 13/13] m68k: mac: convert to generic clockevent

On Fri, Oct 23, 2020 at 11:24 AM Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
> On Fri, Oct 23, 2020 at 9:52 AM Arnd Bergmann <arnd@...nel.org> wrote:
> > On Sun, Oct 18, 2020 at 2:55 AM Finn Thain <fthain@...egraphics.com.au> wrote:
> > > On Thu, 15 Oct 2020, Arnd Bergmann wrote:
> > > > On Thu, Oct 15, 2020 at 3:19 AM Finn Thain <fthain@...egraphics.com.au> 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

FTR, 3.9 KiB reclaimed by upgrading from gcc 8.4.0 in Ubuntu 18.04LTS to
gcc 9.3.0 in Ubuntu 20.04LTS.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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