From owner-freebsd-arch@FreeBSD.ORG Sat Apr 25 18:05:46 2015 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 50FBE4BB; Sat, 25 Apr 2015 18:05:46 +0000 (UTC) Received: from mail-ig0-x22b.google.com (mail-ig0-x22b.google.com [IPv6:2607:f8b0:4001:c05::22b]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 18EB61A50; Sat, 25 Apr 2015 18:05:46 +0000 (UTC) Received: by igblo3 with SMTP id lo3so36274362igb.0; Sat, 25 Apr 2015 11:05:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=h+05ZEZlT9/F2+otprg63CB97Wtuy2EcKrwy+4jDiPI=; b=dEV2E4ZRCvqS4Gp4fNz5HTCUBZ5TDGsgHbbdfc3GTnpefxiqP0bluqwmc/r79FnQ2j z3YuLtIHlOCBSwLquXJccLjm9AAWcLzyfGlSg79XwNFcAv1fxvqeaJOJSLjcqGFQs+ii Rq6biHnd/FPUa1jHx+gRmH+BgJYBKFsvrWXBKVybBUQrZAbJQtHDsdWwE8nybPYdsGIP O5T7T6YfHrSaU4PTm9UhZ4l4VV0RpMIB5IelguKZyWP9f3gM7fi1HhScvKk86vkH4Hst NSuEFHKJHFxJk9LkVDDOwZqXVoA2fyQa+uFAWMGbELTcAuESuOGDGU8gB2Dmg711nA3W eBxg== MIME-Version: 1.0 X-Received: by 10.107.136.25 with SMTP id k25mr4804256iod.88.1429985145555; Sat, 25 Apr 2015 11:05:45 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.36.38.133 with HTTP; Sat, 25 Apr 2015 11:05:45 -0700 (PDT) In-Reply-To: References: Date: Sat, 25 Apr 2015 11:05:45 -0700 X-Google-Sender-Auth: ra7VqadAn-FIXCu5UsmIFmCsH1Y Message-ID: Subject: Re: RFC: setting performance_cx_lowest=C2 in -HEAD to avoid lock contention on many-CPU boxes From: Adrian Chadd To: "K. Macy" Cc: "freebsd-arch@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 Apr 2015 18:05:46 -0000 On 25 April 2015 at 11:02, K. Macy wrote: > Um, don't you care more about power savings when it's on battery? right, that's what I'm changing performance_cx_lowest, and not economy_cx_lowest. performance == AC power economy == battery > On Apr 25, 2015 10:44 AM, "Adrian Chadd" wrote: >> >> Oh the other thing, which I just mentioned to kip in IRC - all of the >> intel laptops I've tested (and that's a long list) don't enter CPU C7 >> if the power is plugged in. >> >> Ie: >> >> * power in, ACPI C2 -> CPU C6 >> * power in, ACPI C3 - CPU C6 >> * battery - ACPI C2 -> CPU C6 >> * battery -> ACPI C3 -> CPU C7 >> >> So having performance_cx_lowest=C3 is effectively a no-op on the >> devices that it'd matter on, so it's okay to just flip it to C2. >> >> >> >> -adrian