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From: David Marchand <david.marchand@6wind.com>
To: Panu Matilainen <pmatilai@redhat.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] eal: default to one memory channel if not specified
Date: Wed, 14 Oct 2015 13:45:09 +0200	[thread overview]
Message-ID: <CALwxeUuz12PmccAvt=kWCKHYzoO4z5LLXCdZd=j4Pyu-4+Butg@mail.gmail.com> (raw)
In-Reply-To: <d209690bda34d966299f000d63c0451b969262b0.1444818124.git.pmatilai@redhat.com>

Hello Panu,

On Wed, Oct 14, 2015 at 12:22 PM, Panu Matilainen <pmatilai@redhat.com>
wrote:

> Obtaining the correct value, especially from a running system, can
> be anything from difficult to plain impossible.  Since the value is
> merely an optimization and does not affect functionality otherwise,
> its pointless to force such a guess on users initially, such things
> belong to performance tuning phase.
>
> Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
> ---
>  lib/librte_eal/common/eal_common_options.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_options.c
> b/lib/librte_eal/common/eal_common_options.c
> index 1f459ac..28f10a2 100644
> --- a/lib/librte_eal/common/eal_common_options.c
> +++ b/lib/librte_eal/common/eal_common_options.c
> @@ -104,7 +104,7 @@ eal_reset_internal_config(struct internal_config
> *internal_cfg)
>
>         internal_cfg->memory = 0;
>         internal_cfg->force_nrank = 0;
> -       internal_cfg->force_nchannel = 0;
> +       internal_cfg->force_nchannel = 1;
>

Well, not too sure about this default value.

- mempool code is already checking for the 0 value.
- API already tells for rte_memory_get_nchannel() :
 *
@return

 *   The number of memory channels on the system. The value is 0 if
unknown
 *   or not the same on all
devices.

So, I would let it 0.


-- 
David Marchand

  reply	other threads:[~2015-10-14 11:45 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-14 10:22 Panu Matilainen
2015-10-14 11:45 ` David Marchand [this message]
2015-10-14 12:04   ` Panu Matilainen
2015-10-14 13:05     ` Bruce Richardson
2015-10-15 11:49 ` [dpdk-dev] [PATCH 0/2] Provide reasonable default to -n Panu Matilainen
2015-10-15 11:49   ` [dpdk-dev] [PATCH 1/2] mempool: use a better default for number of memory channels Panu Matilainen
2015-10-15 11:49   ` [dpdk-dev] [PATCH 2/2] eal: make the -n argument optional Panu Matilainen
2015-10-15 12:03   ` [dpdk-dev] [PATCH 0/2] Provide reasonable default to -n David Marchand
2015-10-26 16:51     ` Thomas Monjalon
2015-10-15 12:10   ` Mcnamara, John
2015-10-15 12:36     ` Panu Matilainen
2015-10-15 13:12       ` Mcnamara, John
2015-10-26 16:50         ` Thomas Monjalon
2015-10-26 16:56   ` Thomas Monjalon
2015-10-27  7:19     ` Panu Matilainen

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