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From: David Laight <David.Laight@ACULAB.COM>
To: 'Kuan-Wei Chiu' <visitorckw@gmail.com>, "akpm@linux-foundation.org"
	<akpm@linux-foundation.org>, "yury.norov@gmail.com" <yury.norov@gmail.com>
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Subject: RE: [PATCH v3 1/2] lib/test_bitops: Add benchmark test for fns()
Thread-Topic: [PATCH v3 1/2] lib/test_bitops: Add benchmark test for fns()
Thread-Index: AQHam5eHsEz2ZjZaTki/tQEkD/csqLGIn56Q
Date: Sun, 5 May 2024 13:03:23 +0000
Message-ID: <44e9ab62e0f543439eb7566a9f134af6@AcuMS.aculab.com>
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 <20240501071647.10228-2-visitorckw@gmail.com>
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From: Kuan-Wei Chiu
> Sent: 01 May 2024 08:17
>=20
> Introduce a benchmark test for the fns(). It measures the total time
> taken by fns() to process 1,000,000 test data generated using
> get_random_long() for each n in the range [0, BITS_PER_LONG).
>=20
> example:
> test_bitops: fns:          5876762553 ns, 64000000 iterations

Great benchmark....

The compiler almost certainly optimises it all away.

Assigning the result of fns() to a file scope (global) volatile int
should stop that happening.

And a real test would actually check the result - just in case
someone does something silly.

=09David

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