From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31E0028DDA for ; Fri, 5 Jan 2024 14:51:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=inria.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=inria.fr Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=inria.fr header.i=@inria.fr header.b="SoMPbgil" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=inria.fr; s=dc; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=JF1aSc64LWeupLUmhqppZtU612Ye+is04mh5J5L6T7M=; b=SoMPbgil+i1vrzct20kWFea6a+pjeq/rHQBX4tfAe/q0vvX5qTIl7HvW al6jfonSRfWTHrZBgASjINm0uWP1Yf4CZ8YQQRlNmsRM04pImH0oIPGFR E8TNztNvYlp8MgjLJQe+0dOwh4KmNVl7JESllOr7x8yyMpZVK1cggdYTG E=; Authentication-Results: mail2-relais-roc.national.inria.fr; dkim=none (message not signed) header.i=none; spf=SoftFail smtp.mailfrom=julia.lawall@inria.fr; dmarc=fail (p=none dis=none) d=inria.fr X-IronPort-AV: E=Sophos;i="6.04,334,1695679200"; d="scan'208";a="145104196" Received: from dt-lawall.paris.inria.fr ([128.93.67.65]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jan 2024 15:51:50 +0100 Date: Fri, 5 Jan 2024 15:51:50 +0100 (CET) From: Julia Lawall To: Vincent Guittot cc: Peter Zijlstra , Ingo Molnar , Dietmar Eggemann , Mel Gorman , linux-kernel@vger.kernel.org Subject: Re: EEVDF and NUMA balancing In-Reply-To: Message-ID: References: <98b3df1-79b7-836f-e334-afbdd594b55@inria.fr> <93112fbe-30be-eab8-427c-5d4670a0f94e@inria.fr> <9dc451b5-9dd8-89f2-1c9c-7c358faeaad@inria.fr> <2359ab5-4556-1a73-9255-3fcf2fc57ec@inria.fr> <6618dcfa-a42f-567c-2a9d-a76786683b29@inria.fr> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII > Your system is calling the polling mode and not the default > cpuidle_idle_call() ? This could explain why I don't see such problem > on my system which doesn't have polling > > Are you forcing the use of polling mode ? > If yes, could you check that this problem disappears without forcing > polling mode ? I expanded the code in do_idle to: if (cpu_idle_force_poll) { c1++; tick_nohz_idle_restart_tick(); cpu_idle_poll(); } else if (tick_check_broadcast_expired()) { c2++; tick_nohz_idle_restart_tick(); cpu_idle_poll(); } else { c3++; cpuidle_idle_call(); } Later, I have: trace_printk("force poll: %d: c1: %d, c2: %d, c3: %d\n",cpu_idle_force_poll, c1, c2, c3); flush_smp_call_function_queue(); schedule_idle(); force poll, c1 and c2 are always 0, and c3 is always some non-zero value. Sometimes small (often 1), and sometimes large (304 or 305). So I don't think it's calling cpu_idle_poll(). x86 has TIF_POLLING_NRFLAG defined to be a non zero value, which I think is sufficient to cause the issue. julia