From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Jan Viktorin <viktorin@rehivetech.com>
Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com,
tomaszx.kulasek@intel.com, jianbo.liu@linaro.org
Subject: Re: [dpdk-dev] [PATCH v3 4/4] eal/arm: introduce CONFIG_RTE_ARCH_ARM_NEON_MEMCPY
Date: Sun, 20 Mar 2016 11:33:37 +0100 [thread overview]
Message-ID: <3300542.bjkaoNcO2a@xps13> (raw)
In-Reply-To: <20160320104655.45a5c863@jvn>
2016-03-20 10:46, Jan Viktorin:
> On Sun, 20 Mar 2016 10:41:10 +0100
> Jan Viktorin <viktorin@rehivetech.com> wrote:
>
> > On Sat, 19 Mar 2016 21:14:57 +0100
> > Thomas Monjalon <thomas.monjalon@6wind.com> wrote:
> >
> > > 2016-03-19 20:58, Jan Viktorin:
> > > > The flag is used to enable memcpy optimizations in EAL. As it is not always
> > > > the performance benefit, the flag allows to disable it.
> > >
> > > Ideally the default should be to choose the best optimization.
> > > If it is not possible, it would help to have some comments explaining
> > > how to choose wether enabling NEON memcpy or not.
>
> The related statistics are mentioned here:
>
> commit 04a2fde35daf5e9a271e72331a70b48b951d7568
> Author: Vlastimil Kosar <kosar@rehivetech.com>
> Date: Tue Nov 3 00:47:20 2015 +0100
>
> eal/arm: add vector memcpy for ARMv7
>
> It's quite difficult to easily summarize it, especially for so many
> CPUs...
If it is difficult for you, it will be impossible for the users of
this config option.
When someone will ask what is the best value for his CPU, what will
you answer?
At least, we can add a comment explaining that the performance is not
always better, depending of the buffer size and the CPU.
next prev parent reply other threads:[~2016-03-20 10:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-19 9:26 [dpdk-dev] [PATCH v2] arm: detect NEON by RTE_MACHINE_CPUFLAG_NEON flag only Jan Viktorin
2016-03-19 11:05 ` Jan Viktorin
2016-03-19 19:58 ` [dpdk-dev] [PATCH v3 0/4] " Jan Viktorin
2016-03-24 16:47 ` Thomas Monjalon
2016-03-19 19:58 ` [dpdk-dev] [PATCH v3 1/4] arm: remove CONFIG_RTE_ARCH_ARM_NEON Jan Viktorin
2016-03-19 19:58 ` [dpdk-dev] [PATCH v3 2/4] arm: detect NEON cpu feature by checking __ARM_NEON Jan Viktorin
2016-03-20 17:27 ` Jerin Jacob
2016-03-19 19:58 ` [dpdk-dev] [PATCH v3 3/4] arm: detect NEON by checking RTE_MACHINE_CPUFLAG_NEON Jan Viktorin
2016-03-19 19:58 ` [dpdk-dev] [PATCH v3 4/4] eal/arm: introduce CONFIG_RTE_ARCH_ARM_NEON_MEMCPY Jan Viktorin
2016-03-19 20:14 ` Thomas Monjalon
2016-03-20 9:41 ` Jan Viktorin
2016-03-20 9:46 ` Jan Viktorin
2016-03-20 10:33 ` Thomas Monjalon [this message]
2016-03-20 10:29 ` Thomas Monjalon
2016-03-20 17:38 ` Jerin Jacob
2016-03-21 5:42 ` Jianbo Liu
2016-03-21 12:21 ` Jan Viktorin
2016-03-21 13:24 ` Thomas Monjalon
2016-03-21 14:01 ` Jan Viktorin
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