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Sat, 22 Feb 2020 14:24:20 +0000 Received: by smtp401.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 08d9970ba44d42f11deb6bf6cb444e34; Sat, 22 Feb 2020 14:24:17 +0000 (UTC) Date: Sat, 22 Feb 2020 09:24:14 -0500 From: "Alex Xu (Hello71)" Subject: Re: [PATCH] kbuild: move -pipe to global KBUILD_CFLAGS To: Nathan Chancellor Cc: Russell King , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, masahiroy@kernel.org, michal.lkml@markovi.net References: <20200222003820.220854-1-alex_y_xu.ref@yahoo.ca> <20200222003820.220854-1-alex_y_xu@yahoo.ca> <20200222021619.GA51223@ubuntu-m2-xlarge-x86> <1582341758.yo66djba3t.none@localhost> <20200222080140.GA40311@ubuntu-m2-xlarge-x86> In-Reply-To: <20200222080140.GA40311@ubuntu-m2-xlarge-x86> MIME-Version: 1.0 Message-Id: <1582381271.1karmgahx0.none@localhost> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Mailer: WebService/1.1.15302 hermes Apache-HttpAsyncClient/4.1.4 (Java/1.8.0_241) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Excerpts from Nathan Chancellor's message of February 22, 2020 3:01 am: > I used hyperfine [1] to run a quick benchmark with a freshly built > GCC 9.2.0 for x86 and aarch64 and here are the results: >=20 > In both cases it seems like performance regresses (by 1% but still) but > maybe it is my machine, even though this benchmark was done on a > different machine than the one from my commit back in 2018. >=20 > I am not sure I would write off these results, since I did the benchmark > 25 times on each one back to back, eliminating most of the variance that > you described. >=20 > [1]: https://github.com/sharkdp/hyperfine >=20 > Cheers, > Nathan >=20 What kernel version are you running? Do you have the 5.6 pipe reworks?