[dpdk-dev] [PATCH] eal: default to one memory channel if not specified
Panu Matilainen
pmatilai at redhat.com
Wed Oct 14 14:04:43 CEST 2015
On 10/14/2015 02:45 PM, David Marchand wrote:
> Hello Panu,
>
> On Wed, Oct 14, 2015 at 12:22 PM, Panu Matilainen <pmatilai at redhat.com
> <mailto:pmatilai at 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 at redhat.com
> <mailto:pmatilai at 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.
Yeah, I noticed it already handles the zero case.
> - 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.
...but missed this one, and thought it'd be "safer" to return some
non-zero value since callers might be expecting it to be a valid -n value.
>
> So, I would let it 0.
Right, so just drop the default value, reword commit message accordingly
and resend. Will do unless there are other objections.
- Panu -
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