From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: buildroot@busybox.net
Subject: [Buildroot] [PATCH] toolchain: get rid of -pipe from optimisations
Date: Sun, 21 Dec 2014 22:05:12 +0100 [thread overview]
Message-ID: <20141221220512.14fe5139@free-electrons.com> (raw)
In-Reply-To: <1419166825-25133-1-git-send-email-yann.morin.1998@free.fr>
Dear Yann E. MORIN,
On Sun, 21 Dec 2014 14:00:25 +0100, Yann E. MORIN wrote:
> -pipe is causing some build failures in Linux kernel >= 3.17.
>
> Also, nowadays, using -pipe does not gain as much as it used to back in
> the days:
>
> Measurements made with a 3.16.7 Linux kernel:
> make linux-depends
> time sh -c 'make linux-build >/dev/null 2>&1'
>
> Without -pipe:
> 716.32user 54.44system 3:42.12elapsed 346%CPU
> 721.22user 54.47system 3:41.81elapsed 349%CPU
> 722.44user 54.00system 3:42.13elapsed 349%CPU
> 721.03user 53.81system 3:41.92elapsed 349%CPU
> 713.21user 53.63system 3:40.51elapsed 347%CPU
> 706.67user 52.42system 3:38.40elapsed 347%CPU
> 714.40user 53.18system 3:40.16elapsed 348%CPU
> 706.01user 53.09system 3:37.87elapsed 348%CPU
> 705.98user 53.01system 3:38.03elapsed 348%CPU
> 714.17user 53.55system 3:39.98elapsed 348%CPU
> Average: 3:40.29elapsed
>
> With -pipe:
> 720.13user 53.90system 3:41.98elapsed 348%CPU
> 713.38user 53.69system 3:40.44elapsed 347%CPU
> 711.60user 52.81system 3:39.06elapsed 348%CPU
> 708.66user 53.09system 3:38.59elapsed 348%CPU
> 711.76user 53.00system 3:38.48elapsed 350%CPU
> 717.85user 53.97system 3:41.77elapsed 348%CPU
> 716.77user 53.77system 3:40.91elapsed 348%CPU
> 717.48user 53.65system 3:41.24elapsed 348%CPU
> 721.44user 55.67system 3:43.45elapsed 347%CPU
> 724.61user 55.63system 3:43.35elapsed 349%CPU
> Average: 3:40.93elapsed
>
> The delta is well in the measurement noise.
>
> Just get rid of it.
>
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Cc: Romain Naour <romain.naour@openwide.fr>
> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
> toolchain/toolchain-common.in | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Applied, thanks.
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-12-21 21:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-21 13:00 [Buildroot] [PATCH] toolchain: get rid of -pipe from optimisations Yann E. MORIN
2014-12-21 21:05 ` Thomas Petazzoni [this message]
2015-01-26 21:51 ` Romain Naour
2015-01-26 21:57 ` Thomas Petazzoni
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