From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id B162AA0032 for ; Fri, 24 Jun 2022 11:45:33 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 44DC440A87; Fri, 24 Jun 2022 11:45:33 +0200 (CEST) Received: from mail-oa1-f49.google.com (mail-oa1-f49.google.com [209.85.160.49]) by mails.dpdk.org (Postfix) with ESMTP id 098914069D for ; Fri, 24 Jun 2022 11:45:32 +0200 (CEST) Received: by mail-oa1-f49.google.com with SMTP id 586e51a60fabf-1013ecaf7e0so3013994fac.13 for ; Fri, 24 Jun 2022 02:45:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=r1bX9ITCvZ317rW3qfLroPsQj24BJCyPOjayjgW8TZ4=; b=YybpH0h+sQYYD0vWkk5Zq4SgEwbLalc/F2nrYY/zhp0jAUHUHxslU7IDGwIeOb1XMr jtCelp+WHk7TZn+fa6GQ6uL6Ui20MGKzPfVq2G1q7/w6ppQkjNN4asshw6w6j+fGP+a9 VNHR3lynHfSlzu04MomeobHqZet5YBG/XQu0n27kxr4SsuYP4caUmDXY2z5/HZmqNyN6 2jZ6a/Ssp7MDKPPk/HsUrICb5WwRXJEQl6KM+bnFif6a4CIT8PnosRl2UPr5lY8S03h6 eCa2syK/AH/B+m425957u1gTaijW3aCbQJKNcvefBODtk7exnWKtdUi9B7dYVYTkrCPN RKbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=r1bX9ITCvZ317rW3qfLroPsQj24BJCyPOjayjgW8TZ4=; b=xMRfGEuXD88JSWwvgHS0LBd1j5uKgM/q13Ul8t0yvEsLdLzRSXJ2gVG6aq+ejBxHGW ABvnEDtcAAvyo3lBszLKuqq0Rhmg1QJGigwRUoMTuolFwb/7/lYmeSQGRt8zeSFpp8J4 EWiBp+hkhDVYJlRPDvP/c3YTLeNYxfWFnJIkw2uVKF0Sj7rG3vYFUESbaaTGgqSAoTjh 9A3w9X9wmCzXmmdSwtYu4TITthVIpK7Zz1fjZCgBXLHSB7Vjwyds9mEc67HRSmSaQk0V Fz8iSHJj5yanjja40t3aMd6UXWX6cWChY4Ehf5saFxWv1fk0JrCRgLJTg0I3EGwWJhZW BudA== X-Gm-Message-State: AJIora//67jJzQVU9z/G8k26wv/G0xtPPAt/8p7cAZR2ThdieseM5t/N sxQp0HDp7JHekeRi5ENZWa3DB6qrqsehZ0zLiaAxCY7GLt0= X-Google-Smtp-Source: AGRyM1vWrwmVZJ+uEZYLtLO4A+BYf5Ov6EmhiS3EtNg+eA4CmvTCo2Xe1ZnBy8H46S035EwdH/yH+e9A+N+J0arjRRs= X-Received: by 2002:a05:6870:f203:b0:108:4a52:da42 with SMTP id t3-20020a056870f20300b001084a52da42mr873195oao.59.1656063931297; Fri, 24 Jun 2022 02:45:31 -0700 (PDT) MIME-Version: 1.0 References: <20220623114159.0fb198b3@hermes.local> In-Reply-To: <20220623114159.0fb198b3@hermes.local> From: Antonio Di Bacco Date: Fri, 24 Jun 2022 11:45:20 +0200 Message-ID: Subject: Re: Large interruptions for EAL thread running on isol core To: Stephen Hemminger Cc: users@dpdk.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org Thank you, didn't know that "System management units" could steal CPU!!! That is scary On Thu, Jun 23, 2022 at 8:42 PM Stephen Hemminger wrote: > > On Thu, 23 Jun 2022 20:03:02 +0200 > Antonio Di Bacco wrote: > > > I'm running a DPDK thread on an isolated core. I also set some flags > > that could help keeping the core at rest on linux like: nosoftlockup > > nohz_full rcu_nocbs irqaffinity. > > > > Unfortunately the thread gets some interruptions that stop the thread > > for about 20-30 micro seconds. This seems smal but my application > > suffers a lot. > > > > I also tried to use rte_thread_set_priority that indeed has a strong > > effect but unfortunately creates problems to Linux (like network not > > working). > > > > Is there any other knob that could help running the DPDK thread with > > minimum or no interruptions at all? > > Look with perf and see what is happening. > First check for interrupt affinity. > Don't try real time priority. > > The other thing to look for would be any BIOS settings. > Some system management units can take away CPU silently for polling > some internal housekeeping.