From owner-freebsd-hackers@FreeBSD.ORG Wed Sep 17 00:38:30 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 111DB575; Wed, 17 Sep 2014 00:38:30 +0000 (UTC) Received: from mail-qg0-x236.google.com (mail-qg0-x236.google.com [IPv6:2607:f8b0:400d:c04::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id AAE58396; Wed, 17 Sep 2014 00:38:29 +0000 (UTC) Received: by mail-qg0-f54.google.com with SMTP id z60so879614qgd.41 for ; Tue, 16 Sep 2014 17:38:28 -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=dqgIVhFvQEbPSjHo7hLPy2ZpDWl9Jc6GTsY2fFuMxG8=; b=Mj8M1qytJt+Tdgq+VLskfKI5iQec8MD/rxuwlh/ajJlGaLmStWmnW3D/o6Dnr/98UI GcFzf8h5VeCLvtbVvxcPp6WeA85vTAF5ShCNuaY4rNSkEyJ9SPupHhAlixjryxHqIDvU Cfw0yABVrb4cRkGs/ilHaMBJT6ACqydwCLeQb14YG7oC3DiARIJO+zDBYwiJv02tXcU2 1yZd295yoITonzMW0JO1vqDjDVIAfAV27Agci6TRrT8k26LG0L0zI6m4WoPfw7tu2k9q vM5G69TeGyKbaf7WsP34vdrGDT6NXAx3hc7tiTBJ3jcRK7nMEljxXZvI8dIyBIaroMRL ocbQ== MIME-Version: 1.0 X-Received: by 10.140.42.77 with SMTP id b71mr54216746qga.52.1410914308634; Tue, 16 Sep 2014 17:38:28 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.224.39.139 with HTTP; Tue, 16 Sep 2014 17:38:28 -0700 (PDT) In-Reply-To: References: <5295A261.2060403@FreeBSD.org> <529F4409.9080403@FreeBSD.org> <52A1B869.6080407@FreeBSD.org> <52A21AE9.5020803@FreeBSD.org> <52A731FD.8060307@FreeBSD.org> Date: Tue, 16 Sep 2014 17:38:28 -0700 X-Google-Sender-Auth: Z1UHp45bi3Jz1saEDb_9JKPIbMM Message-ID: Subject: Re: 9.1 callout behavior From: Adrian Chadd To: Alexander Motin Content-Type: text/plain; charset=UTF-8 Cc: Bret Ketchum , "freebsd-hackers@freebsd.org" X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 17 Sep 2014 00:38:30 -0000 So, it did show up even if I say to run the callout on cpu #0 - any kind of load on that CPU and that callwheel still gets run on another CPU. What I next did was compile up KTR: include GENERIC ident TESTING options KTR options ALQ options KTR_ALQ options KTR_COMPILE=0xffffffff .. then enable KTR_CALLOUT, and I see: 4175 0 884780740167480 precision set for 0xffffffff818194f8: 0.01999997 4174 0 884780667893634 callout lock 0xffffffff818194f8 func 0xffffffff818191d0 arg 0xffffffff818194f8 4149 0 884780455441940 callout 0xffffffff818194f8 finished 4148 0 884780455441414 scheduled 0xffffffff818194f8 func 0xffffffff818191d0 arg 0xffffffff818194f8 in 561.4a5c984a 4147 0 884780455440600 precision set for 0xffffffff818194f8: 0.01999997 4132 0 884780373374060 callout lock 0xffffffff818194f8 func 0xffffffff818191d0 arg 0xffffffff818194f8 4103 0 884780170731868 callout 0xffffffff818194f8 finished 4102 0 884780170731468 scheduled 0xffffffff818194f8 func 0xffffffff818191d0 arg 0xffffffff818194f8 in 561.25c0f291 4101 0 884780170730948 precision set for 0xffffffff818194f8: 0.01999997 4086 0 884780089391348 callout lock 0xffffffff818194f8 func 0xffffffff818191d0 arg 0xffffffff818194f8 4058 0 884779886019688 callout 0xffffffff818194f8 finished .. and those 561.xxxx values are sbintime values. The delta looks like it's ~ 142mS, which is in line with what your callout routine reports. So the math to calculate the "next" event is bumping it along to that value instead of 100mS. I'm going to update one of these boxes to -HEAD and see if it's still a problem there. -a