From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Marchand <david.marchand@redhat.com>
Subject: Re: [PATCH] eal: restrict ctrl threads to startup cpu
	affinity
Date: Thu, 14 Feb 2019 12:05:29 +0100
Message-ID: <CAJFAV8wmJWmzsLqsKteVejSqHZ43yjiajCufGwb40T2Kx=coPg@mail.gmail.com>
References: <1550074412-31285-1-git-send-email-david.marchand@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Cc: Olivier Matz <olivier.matz@6wind.com>, "Burakov,
 Anatoly" <anatoly.burakov@intel.com>,
 Kevin Traynor <ktraynor@redhat.com>, dpdk stable <stable@dpdk.org>
To: dev@dpdk.org
Return-path: <dev-bounces@dpdk.org>
Received: from mail-ua1-f67.google.com (mail-ua1-f67.google.com
 [209.85.222.67]) by dpdk.org (Postfix) with ESMTP id DDAB65F1D
 for <dev@dpdk.org>; Thu, 14 Feb 2019 12:05:41 +0100 (CET)
Received: by mail-ua1-f67.google.com with SMTP id p9so1876615uaa.5
 for <dev@dpdk.org>; Thu, 14 Feb 2019 03:05:41 -0800 (PST)
In-Reply-To: <1550074412-31285-1-git-send-email-david.marchand@redhat.com>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On Wed, Feb 13, 2019 at 5:14 PM David Marchand <david.marchand@redhat.com>
wrote:

> Spawning the ctrl threads on anything that is not part of the eal
> coremask is not that polite to the rest of the system.
>
> Rather than introduce yet another eal options for this, let's take
> the startup cpu affinity as a reference and remove the eal coremask
> from it.
> If no cpu is left, then we default to the master core.
>
> The cpuset is computed once at init before the original cpu affinity.
>
> Fixes: d651ee4919cd ("eal: set affinity for control threads")
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>  lib/librte_eal/common/eal_common_options.c | 28
> ++++++++++++++++++++++++++++
>  lib/librte_eal/common/eal_common_thread.c  | 21 ++++-----------------
>  lib/librte_eal/common/eal_internal_cfg.h   |  3 +++
>  3 files changed, 35 insertions(+), 17 deletions(-)
>
> diff --git a/lib/librte_eal/common/eal_common_options.c
> b/lib/librte_eal/common/eal_common_options.c
> index 6c96f45..b766252 100644
> --- a/lib/librte_eal/common/eal_common_options.c
> +++ b/lib/librte_eal/common/eal_common_options.c
> @@ -1360,6 +1361,31 @@ static int xdigit2val(unsigned char c)
>         cfg->lcore_count -= removed;
>  }
>
> +static void
> +compute_ctrl_threads_cpuset(struct internal_config *internal_cfg)
> +{
> +       rte_cpuset_t *cpuset = &internal_cfg->ctrl_cpuset;
> +       rte_cpuset_t default_set;
> +       unsigned int lcore_id;
> +
> +       for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
> +               if (eal_cpu_detected(lcore_id) &&
> +                               rte_lcore_has_role(lcore_id, ROLE_OFF)) {
> +                       CPU_SET(lcore_id, cpuset);
> +               }
> +       }
> +
> +       if (pthread_getaffinity_np(pthread_self(), sizeof(rte_cpuset_t),
> +                               &default_set) < 0)
> +               CPU_ZERO(&default_set);
>

Now that I am testing on Freebsd, I can see this block I took from the
existing "auto detect" function is just wrong.
pthread_(g|s)etaffinity_np return a > 0 error value when failing.


-- 
David Marchand