From: Carsten Andrich <carsten.andrich@tu-ilmenau.de>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: users@dpdk.org
Subject: Re: Large interruptions for EAL thread running on isol core
Date: Fri, 24 Jun 2022 17:41:44 +0200 [thread overview]
Message-ID: <ef44e436-8e3b-7083-10d8-0dc1602581c8@tu-ilmenau.de> (raw)
In-Reply-To: <20220624080124.244a01a9@hermes.local>
I cannot find SCHED_NO_HZ_FULL in v5.18:
https://elixir.bootlin.com/linux/latest/A/ident/SCHED_NO_HZ_FULL
Could you elaborate?
Thanks and best regards,
Carsten
On 24.06.22 17:01, Stephen Hemminger wrote:
> On Thu, 23 Jun 2022 21:03:49 +0200
> Carsten Andrich <carsten.andrich@tu-ilmenau.de> wrote:
>
>> 2. Use real-time priority (SCHED_FIFO w/ priority 99) for the DPDK
>> threads and
>> echo -1 > /proc/sys/kernel/sched_rt_runtime_us
>> to disable the runtime limit. With the runtime limit in place, the
>> SCHED_FIFO performance will be significantly worse than SCHED_OTHER.
> This can cause major issues if application is normal DPDK application (never does system calls).
> If an interrupt or other event happens on your isolated CPU, the work that it would
> do in soft irq is never performed. FIFO has higher priority than kernel threads.
> This can lead to mystery lockups from other applications (reads not completing, network timeouts, etc).
>
> In any semi-recent kernel using SCHED_NO_HZ_FULL will keep clock ticks from happening
> on the isolated cores.
next prev parent reply other threads:[~2022-06-24 15:41 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-23 18:03 Antonio Di Bacco
2022-06-23 18:07 ` Omer Yamac
2022-06-24 9:43 ` Antonio Di Bacco
2022-06-23 18:41 ` Stephen Hemminger
2022-06-24 9:45 ` Antonio Di Bacco
2022-06-24 10:43 ` Kinsella, Ray
2022-06-23 19:03 ` Carsten Andrich
2022-06-24 15:01 ` Stephen Hemminger
2022-06-24 15:41 ` Carsten Andrich [this message]
2022-06-24 16:42 ` Stephen Hemminger
2022-06-28 7:25 ` Carsten Andrich
2022-06-28 15:19 ` Stephen Hemminger
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