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Date: Wed, 10 Jan 2024 17:17:39 +1100
From: Stephen Rothwell <sfr@canb.auug.org.au>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Slaby <jirislaby@gmail.com>, David Laight
 <David.Laight@aculab.com>, "linux-kernel@vger.kernel.org"
 <linux-kernel@vger.kernel.org>, Andy Shevchenko
 <andriy.shevchenko@linux.intel.com>, Andrew Morton
 <akpm@linux-foundation.org>, "Matthew Wilcox (Oracle)"
 <willy@infradead.org>, Christoph Hellwig <hch@infradead.org>, "Jason A.
 Donenfeld" <Jason@zx2c4.com>
Subject: Re: [PATCH next v4 0/5] minmax: Relax type checks in min() and
 max().
Message-ID: <20240110171739.2e2d9de0@canb.auug.org.au>
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Hi Linus,

On Mon, 8 Jan 2024 13:11:12 -0800 Linus Torvalds <torvalds@linux-foundation=
org> wrote:
>
> Whee.

Yeah.

> On my machine, that patch makes an "allmodconfig" build go from
>=20
>     10:41 elapsed
>=20
> to
>=20
>      8:46 elapsed
>=20
> so that min/max type checking is almost 20% of the build time.
>=20
> Yeah, I think we need to get rid of it.
>=20
> Can somebody else confirm similar time differences? Or is it just me?

I was hopeful, but:

no patch:

$ /usr/bin/time make ARCH=3Dx86_64 CROSS_COMPILE=3Dx86_64-linux-gnu- -j140 =
-O -s
102460.07user 3710.56system 13:29.05elapsed 13122%CPU (0avgtext+0avgdata 40=
23168maxresident)k
304inputs+7917056outputs (1998673major+120730959minor)pagefaults 0swaps

with patch:

$ /usr/bin/time make ARCH=3Dx86_64 CROSS_COMPILE=3Dx86_64-linux-gnu- -j140 =
-O -s
99775.75user 3684.45system 13:12.89elapsed 13048%CPU (0avgtext+0avgdata 221=
7536maxresident)k
64inputs+7890304outputs (2104371major+119837267minor)pagefaults 0swaps

$ x86_64-linux-gnu-gcc --version
x86_64-linux-gnu-gcc (Debian 13.2.0-7) 13.2.0
$ lscpu
Architecture:           ppc64le
  Byte Order:           Little Endian
CPU(s):                 160
  On-line CPU(s) list:  0-159
Model name:             POWER9, altivec supported
  Model:                2.2 (pvr 004e 1202)
  Thread(s) per core:   4
  Core(s) per socket:   20
  Socket(s):            2

--=20
Cheers,
Stephen Rothwell

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