Date: Sat, 19 Nov 2022 14:48:04 -0800 From: Kevin Oberman <rkoberman@gmail.com> To: Ian Smith <smithi@nimnet.asn.au> Cc: mike tancsa <mike@sentex.net>, questions@freebsd.org Subject: Re: RELENG_13 and min cpu frequency Message-ID: <CAN6yY1v59%2BUeHuOZBVeK%2BsN694u=xjA7CyXOiOMEXtkgZfYQFA@mail.gmail.com> In-Reply-To: <BF5CF7F7-DBB3-45A5-9FFA-7595EF41D494@nimnet.asn.au> References: <9d17ea30-4b10-2aa3-9d09-017da7423844@sentex.net> <BF5CF7F7-DBB3-45A5-9FFA-7595EF41D494@nimnet.asn.au>
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--00000000000076b59c05edda9ecd Content-Type: text/plain; charset="UTF-8" On Fri, Nov 18, 2022 at 9:41 PM Ian Smith <smithi@nimnet.asn.au> wrote: > On 19 November 2022 8:28:45 am AEDT, mike tancsa <mike@sentex.net> wrote: > > Hi mike, > > > I noticed that when I moved from an old RELENG11 to RELENG13 > > firewall, I > > was starting to get dropped packets. > > excuse savage pruning; phone ... > > > e.g. printing it out every second, I see > > > > while true > > do > > /sbin/sysctl -n dev.cpu.0.freq > > sleep 1 > > done > > > > 4308 > > 4308 > > 4308 > > 4308 > > 1902 > > 900 > > 900 > > 900 > > 4308 > > 4308 > > 4308 > > 4308 > > 4308 > > > > Whats the best way to set the box NOT to scale down the CPU below > > a > > certain frequency ? I want to see if not letting it drop below 3000 > > prevents packet overruns when there is a burst of traffic from a time > > of > > things being quiet ? > > > > Setting debug.cpufreq.lowest: to 3000 does not seem to make a > > difference > > I see below that it's 0 .. didn't it take, or was that another time? > > > dev.cpu.0.freq_levels: 3400/-1 > > dev.cpu.0.freq: 1302 > > So, hmm. powerd reads and sets values in dev.cpu.0.freq_levels, hence > can't change it to anything but 3400. > > So how is cpu.0.freq changing at all? Is cpufreq using est(4)? Are there > more freqs in dev.est.0.freq_settings? > > Or is it using a _relative_ driver like acpi_throttle or p4tcc? Default > /boot/device.hints has both of these disabled for good reason (Kevin > Oberman can elaborate) > > > sysctl -A debug.cpufreq > > debug.cpufreq.verbose: 0 > > debug.cpufreq.lowest: 0 > > > > > > CPU is CPU: Intel(R) Xeon(R) E-2226G CPU @ 3.40GHz > > (3400.00-MHz K8-class CPU) > > Also noted that the usual +1 freq for turbo mode isn't there. Strange? > (I don't speak Xeon though) > > cheers, Ian > In recent processors, things have changed radically WRT CPU frequency and thermal behavior. I have an Alder Lake system (12th gen) and a Comet Lake (10th gen). Both now show a single frequency. On my Alder Lake I see: dev.cpu.?.freq_levels: 2496/-1 This is shown for all CPU devices (threads) whether P or E cores. Thermal control does change these seeds continually. I have seen E cores at 900M, but rarely. I see them as 1.2G during buildworld. The P cores are at 1.3G. I have never seen ANY core running at over 2.5G. When I ordered my T16, the specs showed minimum, default, and maximum frequencies, but I can't find them any longer. All I can find are "Minimum" and "Max Turbo". It's not clear to me what the significance of this is, but it was clearly a decision of Intel. To me, it implies that Turbo is really no longer distinct , but considered a portion of a continuum of frequencies. Just looked again. buildworld is still running, and see all CPUs are at 2094, 2095, 2096, and 2097. A few seconds later, 1997 to 2094. All CPUs are not always running at very similar speeds. This is very different from anything I have seen on older processors. I see no distinction between P and E cores. I also suspect that powerd is no longer relevant for modern CPUs. Anyone have a pointer to information on CPU frequency and thermal management on newer Intel processors? -- Kevin Oberman, Part time kid herder and retired Network Engineer E-mail: rkoberman@gmail.com PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683 --00000000000076b59c05edda9ecd Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div dir=3D"ltr"><div class=3D"gmail_default" style=3D"fon= t-family:tahoma,sans-serif;font-size:small"><br></div></div><br><div class= =3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Fri, Nov 18, 2022= at 9:41 PM Ian Smith <<a href=3D"mailto:smithi@nimnet.asn.au">smithi@ni= mnet.asn.au</a>> wrote:<br></div><blockquote class=3D"gmail_quote" style= =3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding= -left:1ex">On 19 November 2022 8:28:45 am AEDT, mike tancsa <<a href=3D"= mailto:mike@sentex.net" target=3D"_blank">mike@sentex.net</a>> wrote:<br= > <br> Hi mike,<br> <br> =C2=A0> I noticed that when I moved from an old RELENG11 to RELENG13<br> =C2=A0> firewall, I <br> =C2=A0> was starting to get dropped packets.<br> <br> excuse savage pruning; phone ...<br> <br> =C2=A0> e.g. printing it out every second, I see<br> =C2=A0> <br> =C2=A0> while true<br> =C2=A0> do<br> =C2=A0> /sbin/sysctl -n dev.cpu.0.freq<br> =C2=A0> sleep 1<br> =C2=A0> done<br> =C2=A0> <br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> 1902<br> =C2=A0> 900<br> =C2=A0> 900<br> =C2=A0> 900<br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> 4308<br> =C2=A0> <br> =C2=A0> =C2=A0=C2=A0 Whats the best way to set the box NOT to scale down= the CPU below<br> =C2=A0> a <br> =C2=A0> certain frequency ? I want to see if not letting it drop below 3= 000 <br> =C2=A0> prevents packet overruns when there is a burst of traffic from a= time<br> =C2=A0> of <br> =C2=A0> things being quiet ?<br> =C2=A0> <br> =C2=A0> Setting debug.cpufreq.lowest: to 3000 does not seem to make a<br= > =C2=A0> difference<br> <br> I see below that it's 0 .. didn't it take, or was that another time= ?<br> <br> =C2=A0> dev.cpu.0.freq_levels: 3400/-1<br> =C2=A0> dev.cpu.0.freq: 1302<br> <br> So, hmm.=C2=A0 powerd reads and sets values in dev.cpu.0.freq_levels, hence= can't change it to anything but 3400.<br> <br> So how is cpu.0.freq changing at all?=C2=A0 Is cpufreq using est(4)?=C2=A0 = Are there more freqs in dev.est.0.freq_settings?<br> <br> Or is it using a _relative_ driver like acpi_throttle or p4tcc?=C2=A0 Defau= lt /boot/device.hints has both of these disabled for good reason (Kevin Obe= rman can elaborate)<br> <br> =C2=A0> sysctl -A debug.cpufreq<br> =C2=A0> debug.cpufreq.verbose: 0<br> =C2=A0> debug.cpufreq.lowest: 0<br> =C2=A0> <br> =C2=A0> <br> =C2=A0> CPU is CPU: Intel(R) Xeon(R) E-2226G CPU @ 3.40GHz<br> =C2=A0> (3400.00-MHz K8-class CPU)<br> <br> Also noted that the usual +1 freq for turbo mode isn't there.=C2=A0 Str= ange?=C2=A0 (I don't speak Xeon though)<br> <br> cheers, Ian<br></blockquote><div><br></div><div style=3D"font-family:tahoma= ,sans-serif;font-size:small" class=3D"gmail_default">In recent processors, = things have changed radically WRT CPU frequency and thermal behavior.</div>= <div style=3D"font-family:tahoma,sans-serif;font-size:small" class=3D"gmail= _default"><br></div><div style=3D"font-family:tahoma,sans-serif;font-size:s= mall" class=3D"gmail_default">I have an Alder Lake system (12th gen) and a = Comet Lake (10th gen). Both now show a single frequency. On my Alder Lake I= see:</div><div style=3D"font-family:tahoma,sans-serif;font-size:small" cla= ss=3D"gmail_default">dev.cpu.?.freq_levels: 2496/-1</div><div style=3D"font= -family:tahoma,sans-serif;font-size:small" class=3D"gmail_default">This is = shown for all CPU devices (threads) whether P or E cores. Thermal control d= oes change these seeds continually. I have seen E cores at 900M, but rarely= . I see them as 1.2G during buildworld. The P cores are at 1.3G. I have nev= er seen ANY core running at over 2.5G. When I ordered my T16, the specs sho= wed minimum, default, and maximum frequencies, but I can't find them an= y longer. All I can find are "Minimum" and "Max Turbo".= It's not clear to me what the significance of this is, but it was clea= rly a decision of Intel. To me, it implies that Turbo is really no longer d= istinct , but considered a portion of a continuum of frequencies.</div><div= style=3D"font-family:tahoma,sans-serif;font-size:small" class=3D"gmail_def= ault"><br></div><div style=3D"font-family:tahoma,sans-serif;font-size:small= " class=3D"gmail_default">Just looked again. buildworld is still running, a= nd see all CPUs are at 2094, 2095, 2096, and 2097.=C2=A0=C2=A0 A few second= s later, 1997 to 2094. All CPUs are not always running at very similar spee= ds. This is very different from anything I have seen on older processors. I= see no distinction between P and E cores. I also suspect that powerd is no= longer relevant for modern CPUs.=C2=A0 Anyone have a pointer to informatio= n on CPU frequency and thermal management on newer Intel processors?<br></d= iv></div>-- <br><div dir=3D"ltr" class=3D"gmail_signature"><div dir=3D"ltr"= ><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr">Kevin Ob= erman, Part time kid herder and retired Network Engineer<br>E-mail: <a href= =3D"mailto:rkoberman@gmail.com" target=3D"_blank">rkoberman@gmail.com</a><b= r></div><div>PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683</div= ></div></div></div></div></div></div></div></div> --00000000000076b59c05edda9ecd--
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