From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot0-x242.google.com (mail-ot0-x242.google.com [IPv6:2607:f8b0:4003:c0f::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id EFD273B29E for ; Wed, 25 Jan 2017 16:31:58 -0500 (EST) Received: by mail-ot0-x242.google.com with SMTP id f9so25149662otd.0 for ; Wed, 25 Jan 2017 13:31:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=2T0OETTZLfXA5d1GAsKIhTs54H0PjFyZIsoUXEQZagY=; b=QSH63FQF3afQChVygRDRwJmsL0QxVILCXiB3TibeoragKYif1U/GB35JeEgKEJ594g BTOTWsAxL7b9Eq72f25Sf9XDV/LBGNHMEtZsYbaSqC8Hsu28ifZAXMxPRgLlE+fNPgIG ZxV8sjY1aOx3HfJa2m0UdchZyruSOFnmyskVX61D1SefkBEwIEVT3n5ZJScDvZgMwWZA zOwknHymzPggegdzc/FfsuSWIGfAU7ddIHcGRP5wZlzgoQfENF6JN4fUTBXqDblCnigM ZDdKI3vWt4BADxZwDj8iD3HGdLKFVy6lVNtO82n6XS8V9lgL6D0yfLwdNE1R2yHoUsN6 6Pwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=2T0OETTZLfXA5d1GAsKIhTs54H0PjFyZIsoUXEQZagY=; b=PwHhaInG8yXSjEdOdWQr7CT3IIOMvFDEcziM1epXZVtvaFWlk64rSafOiwVqVL8L+i 9uq2X8P8BfF9aAt4TRpVSFIad7PufZwT6XGMs0UvYIe8JjMCQbrQbRX7PXMWfRkfCMra JK2z/en7/pvcYDD9fd0Jj3fLhZwOh55oYaLkJ2/7FUHMQmdSLXeAUUeKYy1zZKmzDoLc SGmnpscwuc4Cvp1yB1+s0hCOYl/O06deh4RMEq/kWVN5tlqUBWybR1+POagHscPSb9cO 5OLifozT5kuTYkrtaCdvJxmeOPu8r6EUqGP3eWsNrfx1pRAlosmpz2xuZA03rv3wFgub u70A== X-Gm-Message-State: AIkVDXKBvwPGbttDKQ2OaZcV1dDQoak6eO6s6s1yMJ5D50DO1dZO2GRZHPnTDOxEBphQk4/d3JWhEC+/hAJb0A== X-Received: by 10.157.4.1 with SMTP id 1mr18026224otc.205.1485379918395; Wed, 25 Jan 2017 13:31:58 -0800 (PST) MIME-Version: 1.0 Received: by 10.157.1.21 with HTTP; Wed, 25 Jan 2017 13:31:58 -0800 (PST) In-Reply-To: References: <58D7E8D3-5661-4126-80D9-2F2D4E478B10@gmail.com> <908CA0EF-3D84-4EB4-ABD8-3042668E842E@gmail.com> <8B89C257-99D4-4A9A-96ED-A103A2089A46@gmail.com> From: Hans-Kristian Bakke Date: Wed, 25 Jan 2017 22:31:58 +0100 Message-ID: To: Jonathan Morton Cc: bloat@lists.bufferbloat.net Content-Type: multipart/alternative; boundary=001a113b136c6480420546f1f639 Subject: Re: [Bloat] Initial tests with BBR in kernel 4.9 X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 Jan 2017 21:31:59 -0000 --001a113b136c6480420546f1f639 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable kvm-clock is a paravirtualized clock that seems to use the CPUs TSC capabilities if they exist. But it may not be perfect: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/ht= ml/Virtualization_Host_Configuration_and_Guest_Installation_Guide/chap-Virt= ualization_Host_Configuration_and_Guest_Installation_Guide-KVM_guest_timing= _management.html On 25 January 2017 at 22:29, Hans-Kristian Bakke wrote: > Actually I think that is because it may be using the newer TSC: > dmesg | grep clocksource > [ 0.000000] clocksource: kvm-clock: mask: 0xffffffffffffffff > max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns > [ 0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: > 0xffffffff, max_idle_ns: 7645519600211568 ns > [ 0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff= , > max_idle_ns: 19112604467 ns > [ 0.092665] clocksource: jiffies: mask: 0xffffffff max_cycles: > 0xffffffff, max_idle_ns: 7645041785100000 ns > [ 0.366429] clocksource: Switched to clocksource kvm-clock > [ 0.378974] clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, > max_idle_ns: 2085701024 ns > [ 1.666474] tsc: Refined TSC clocksource calibration: 3200.013 MHz > [ 1.666479] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: > 0x2e20562a1bb, max_idle_ns: 440795285529 ns > > > On 25 January 2017 at 22:26, Jonathan Morton > wrote: > >> >> > On 25 Jan, 2017, at 23:20, Hans-Kristian Bakke >> wrote: >> > >> > =E2=80=8B[ 0.000000] ACPI: HPET 0x00000000BFFE274F 000038 (v01 BOCH= S >> BXPCHPET 00000001 BXPC 00000001) >> > [ 0.000000] ACPI: HPET id: 0x8086a201 base: 0xfed00000 >> > [ 0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: >> 0xffffffff, max_idle_ns: 19112604467 ns >> > [ 0.000000] hpet clockevent registered >> > [ 0.362335] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0 >> > [ 0.362339] hpet0: 3 comparators, 64-bit 100.000000 MHz counter >> > [ 0.661731] rtc_cmos 00:00: alarms up to one day, y3k, 114 bytes >> nvram, hpet irqs >> >> Conspicuously absent here is a line saying =E2=80=9Cclocksource: Switche= d to >> clocksource hpet=E2=80=9D. That may be worth examining in more detail. >> >> - Jonathan Morton >> >> > --001a113b136c6480420546f1f639 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

On 25 January 2017 at 22:29, Hans-Kr= istian Bakke <hkbakke@gmail.com> wrote:
Actually I think that is because it may be using = the newer TSC:
=C2=A0dmesg | grep clocksource<= /div>
[ =C2=A0 =C2=A00.000000] clocksource: kvm= -clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 88= 1590591483 ns
[ =C2=A0 =C2=A00.000000] cl= ocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_id= le_ns: 7645519600211568 ns
[ =C2=A0 =C2=A00.000000] clocksource: hpet: mask: 0xffffffff max_cycles:= 0xffffffff, max_idle_ns: 19112604467 ns
[ =C2=A0 =C2=A00.092665] clocksource: jiffies: mask: 0xffffffff max_= cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[ =C2=A0 =C2=A00.366429] clocksource: Switched to clocksource k= vm-clock
[ =C2=A0 =C2=A00.378974] clockso= urce: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 2085701024= ns
[ =C2=A0 =C2=A01.666474] tsc: Refined= TSC clocksource calibration: 3200.013 MHz
[ =C2=A0 =C2=A01.666479] clocksource: tsc: mask: 0xffffffffffffffff max_c= ycles: 0x2e20562a1bb, max_idle_ns: 440795285529 ns

=
On 25 January 2017 at 22:26, Jonathan Morton= <chromatix99@gmail.com> wrote:

> On 25 Jan, 2017, at 23:20, Hans-Kristian Bakke <hkbakke@gmail.com> wrote:
>
> =E2=80=8B[=C2=A0 =C2=A0 0.000000] ACPI: HPET 0x00000000BFFE274F 000038= (v01 BOCHS=C2=A0 BXPCHPET 00000001 BXPC 00000001)
> [=C2=A0 =C2=A0 0.000000] ACPI: HPET id: 0x8086a201 base: 0xfed00000 > [=C2=A0 =C2=A0 0.000000] clocksource: hpet: mask: 0xffffffff max_cycle= s: 0xffffffff, max_idle_ns: 19112604467 ns
> [=C2=A0 =C2=A0 0.000000] hpet clockevent registered
> [=C2=A0 =C2=A0 0.362335] hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0
> [=C2=A0 =C2=A0 0.362339] hpet0: 3 comparators, 64-bit 100.000000 MHz c= ounter
> [=C2=A0 =C2=A0 0.661731] rtc_cmos 00:00: alarms up to one day, y3k, 11= 4 bytes nvram, hpet irqs

Conspicuously absent here is a line saying =E2=80=9Cclocksource: Swi= tched to clocksource hpet=E2=80=9D.=C2=A0 That may be worth examining in mo= re detail.

=C2=A0- Jonathan Morton



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