From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas Pandruvada Subject: Re: [PATCH v2] Documentation: cpufreq: intel_pstate: enhance documentation Date: Mon, 28 Dec 2015 16:44:16 -0800 Message-ID: <5681D760.6090309@linux.intel.com> References: <1451326526-6367-1-git-send-email-srinivas.pandruvada@linux.intel.com> <36DF59CE26D8EE47B0655C516E9CE6402869140A@shsmsx102.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mga09.intel.com ([134.134.136.24]:13430 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257AbbL2Aoh (ORCPT ); Mon, 28 Dec 2015 19:44:37 -0500 In-Reply-To: <36DF59CE26D8EE47B0655C516E9CE6402869140A@shsmsx102.ccr.corp.intel.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Chen, Yu C" , "dsmythies@telus.net" Cc: "Brown, Len" , "linux-pm@vger.kernel.org" , "rafael@kernel.org" On 12/28/2015 04:17 PM, Chen, Yu C wrote: > Hi, > >> -----Original Message----- >> From: linux-pm-owner@vger.kernel.org [mailto:linux-pm- >> owner@vger.kernel.org] On Behalf Of Srinivas Pandruvada >> Sent: Tuesday, December 29, 2015 2:15 AM >> To: rafael@kernel.org; dsmythies@telus.net >> Cc: Brown, Len; linux-pm@vger.kernel.org; Srinivas Pandruvada >> Subject: [PATCH v2] Documentation: cpufreq: intel_pstate: enhance >> documentation >> >> This is an attempt to make documentation more user friendly. >> >> Signed-off-by: Srinivas Pandruvada >> --- >> Changes in v2: >> Suggested by Doug Smythies >> - Grammar correction >> - Use default PID and impact of setpoint on ramp up times >> >> >> Documentation/cpu-freq/intel-pstate.txt | 193 >> +++++++++++++++++++++++++------- >> 1 file changed, 151 insertions(+), 42 deletions(-) >> >> diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation= /cpu- >> freq/intel-pstate.txt >> index be8d400..5398a66 100644 >> --- a/Documentation/cpu-freq/intel-pstate.txt >> +++ b/Documentation/cpu-freq/intel-pstate.txt >> @@ -1,61 +1,131 @@ >> -Intel P-state driver >> +Intel P-State driver >> -------------------- >> >> +For the same load at setpoint =3D 60, this will result in the next >> +P-State =3D 0x08 - ((60 - 100) * 0.2) =3D 16 So by changing the set= point >> +from 97 to 60, there is an increase of the next P-State from 9 to 1= 6. >> +So this will make processor execute at higher P-State for the same = CPU >> +load. If the load continues to be more than the setpoint during nex= t >> +sample intervals, then P-State will go up again till the maximum >> +P-State is reached. But the ramp up time to reach the maximum P-Sta= te >> +will be much faster when the setpoint is 60 compared to 97. >> -- > Just inspired by another thread in the maillist, how about adding a d= escription > on suggesting enable the ftrace when user is trying to do some debu= g/tuning? > Good idea. Will add to next version. Thanks, Srinivas > thanks, > yu > N=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BDr=EF=BF=BD=EF=BF=BDy=EF= =BF=BD=EF=BF=BD=EF=BF=BDb=EF=BF=BDX=EF=BF=BD=EF=BF=BD=C7=A7v=EF=BF=BD^=EF= =BF=BD)=DE=BA{.n=EF=BF=BD+=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD{=EF=BF=BD= =EF=BF=BDh=EF=BF=BD=EF=BF=BD=17=EF=BF=BD=EF=BF=BD=DC=A8}=EF=BF=BD=EF=BF= =BD=EF=BF=BD=C6=A0z=EF=BF=BD&j:+v=EF=BF=BD=EF=BF=BD=EF=BF=BD=07=EF=BF=BD= =EF=BF=BD=EF=BF=BD=EF=BF=BDzZ+=EF=BF=BD=EF=BF=BD+zf=EF=BF=BD=EF=BF=BD=EF= =BF=BDh=EF=BF=BD=EF=BF=BD=EF=BF=BD~=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD= i=EF=BF=BD=EF=BF=BD=EF=BF=BDz=EF=BF=BD=1E=EF=BF=BDw=EF=BF=BD=EF=BF=BD=EF= =BF=BD?=EF=BF=BD=EF=BF=BD=EF=BF=BD=EF=BF=BD&=EF=BF=BD)=DF=A2=1Bfl=3D=3D= =3D >