From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 18C632F3623; Thu, 8 Jan 2026 22:07:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767910061; cv=none; b=eYR5qD1wRhG7AjWrarZ1PDzGAKlWCvKouxbIVt49mVyf0XDnC+/DnWy0KlmZVmmIYsEJzHobd8+ua53JfhyCZQ1PuSqVSTuAwcnnnYupbVsgfstDtvFWPuvyQGs9ay1T6WtyP09uVVULqfWbGhLH3V+jlEu07YZBdHAr9YSS1Lo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767910061; c=relaxed/simple; bh=XA1F8ZQy3SAZM8CQ9bPudZSO/2AYK/jiVqRKHtV+8qI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HgAsJtLMvu05IO8/7e7ZyTRFf8oo2quUvIGSY1Jrtcih8gdBQrE5qVTjdTi++/j4W+jnogls7vRXCfZFiAEDFFITV3/8gygGVmsXEfdA9Kx7Fzb5nje6Jnqa2u7rNXOtEky3EZ5r6NRZQCcR65ilZj6fYpjyKp6gItvKlAjk9Jc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=knXdA+HA; arc=none smtp.client-ip=198.175.65.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="knXdA+HA" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1767910061; x=1799446061; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=XA1F8ZQy3SAZM8CQ9bPudZSO/2AYK/jiVqRKHtV+8qI=; b=knXdA+HA2PMpTtjzZfx/1BIy+kR8DSJR1Kbrxyu+baQK+8FiXPu+zco9 Vsaj58Wi9rBOOGm+GqCzLskyAaDiCZIpLLgFKOccxtcAjXVfksBw34lMG KBBzfHqtpYeIANuOLpEdJAFI1uT9qR9DhsN6b6iceXEIdjMZA8/cnFDvW IOjtmAxmB5flTyDOBJcWEEC6T+9DFMB0g0bbqhRjK4kjGvHiMa+ZBs6wy 1nKsLgmlKyQJZwccX3FffYlxn7beCdU0cOGJP7G64cqGWopFLE6mTMdhD wDJuUvdqhe2KO1dje7mRTbm9neucnzyaAQ1Lpv4tVDtFwogdxh8cTXwnG A==; X-CSE-ConnectionGUID: 7mj8TJBfQTCuMwa6sYsTWg== X-CSE-MsgGUID: lGpvgo9DTAOBU79zb+/F0A== X-IronPort-AV: E=McAfee;i="6800,10657,11665"; a="80744729" X-IronPort-AV: E=Sophos;i="6.21,211,1763452800"; d="scan'208";a="80744729" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jan 2026 14:07:40 -0800 X-CSE-ConnectionGUID: JdCq2IGRTPCNQCw6C/Cn8w== X-CSE-MsgGUID: Nv+RPMReSfKPsqw2tsXFow== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,211,1763452800"; d="scan'208";a="240807445" Received: from tassilo.jf.intel.com (HELO tassilo) ([10.54.38.190]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jan 2026 14:07:39 -0800 Date: Thu, 8 Jan 2026 14:07:35 -0800 From: Andi Kleen To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Adrian Hunter , "Dr. David Alan Gilbert" , Yang Li , James Clark , Thomas Falcon , Thomas Richter , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Dapeng Mi Subject: Re: [PATCH v6 3/3] perf stat: Add no-affinity flag Message-ID: References: <20260108212652.768875-1-irogers@google.com> <20260108212652.768875-4-irogers@google.com> 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 Content-Disposition: inline In-Reply-To: <20260108212652.768875-4-irogers@google.com> On Thu, Jan 08, 2026 at 01:26:52PM -0800, Ian Rogers wrote: > Add flag that disables affinity behavior. Using sched_setaffinity to > place a perf thread on a CPU can avoid certain interprocessor > interrupts but may introduce a delay due to the scheduling, > particularly on loaded machines. Add a command line option to disable > the behavior. This behavior is less present in other tools like `perf > record`, as it uses a ring buffer and doesn't make repeated system > calls. I thought we had agreed that this change isn't needed? -Andi