Date: Wed, 21 Mar 2012 17:55:34 +0100 From: Olivier Smedts <olivier@gid0.org> To: Kevin Oberman <kob6558@gmail.com> Cc: Matthias Gamsjager <mgamsjager@gmail.com>, freebsd-stable@freebsd.org, John <john@theusgroup.com> Subject: Re: powerd and increase in energy need Message-ID: <CABzXLYOeVfsWxcinYntCpVkgnoOrPxpTia_4=4EXhQ-KquArpg@mail.gmail.com> In-Reply-To: <CAN6yY1tKYbTjgQsL1gnfrc9r68c%2BQDCb1SAb%2BM=RFA90jvLpnw@mail.gmail.com> References: <CA%2BD9Qhv5EmrkqvLetx9T5WD_1BRuCpUyZ=VYnRSjwRYqA7phdg@mail.gmail.com> <20120321000058.177F8256@server.theusgroup.com> <CA%2BD9QhsMMXYbLKg__jZx=7KbCHtK6LjqkfL9WSWs=pdT-t9r0w@mail.gmail.com> <CAN6yY1tKYbTjgQsL1gnfrc9r68c%2BQDCb1SAb%2BM=RFA90jvLpnw@mail.gmail.com>
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2012/3/21 Kevin Oberman <kob6558@gmail.com>: > If you are trying to reduce power consumption, why are you limiting Cx > states to C2 (which save little) and not C3 (which will save a LOT of > power when the CPU is not heavily loaded). Jumping up on this but I don't know if that's related to his reasons to not use C3. Mine are simple : # sysctl dev.cpu | grep temperature dev.cpu.0.temperature: 39,0C dev.cpu.1.temperature: 40,0C dev.cpu.2.temperature: 36,0C dev.cpu.3.temperature: 36,0C dev.cpu.4.temperature: 41,0C dev.cpu.5.temperature: 41,0C dev.cpu.6.temperature: 36,0C dev.cpu.7.temperature: 36,0C # sysctl hw.acpi.cpu.cx_lowest=3DC3 hw.acpi.cpu.cx_lowest: C2 -> C3 # sysctl dev.cpu | grep temperature dev.cpu.0.temperature: 44,0C dev.cpu.1.temperature: 44,0C dev.cpu.2.temperature: 40,0C dev.cpu.3.temperature: 40,0C dev.cpu.4.temperature: 46,0C dev.cpu.5.temperature: 46,0C dev.cpu.6.temperature: 41,0C dev.cpu.7.temperature: 41,0C # sysctl hw.acpi.cpu.cx_lowest=3DC2 hw.acpi.cpu.cx_lowest: C3 -> C2 # sysctl dev.cpu | grep temperature dev.cpu.0.temperature: 40,0C dev.cpu.1.temperature: 40,0C dev.cpu.2.temperature: 36,0C dev.cpu.3.temperature: 36,0C dev.cpu.4.temperature: 42,0C dev.cpu.5.temperature: 42,0C dev.cpu.6.temperature: 36,0C dev.cpu.7.temperature: 36,0C Only 1-2 seconds between each command, no current load. As you can see, when I engage C3 states, the CPU temperature increases by 4-5=B0C. I expected it to drop. This is with : # sysctl dev.cpu | grep freq dev.cpu.0.freq: 2933 dev.cpu.0.freq_levels: 2933/95 2799/95 2266/75 1733/56 1199/39 # grep perf /etc/rc.conf performance_cx_lowest=3D"C2" performance_cpu_freq=3D"HIGH" # grep hint /boot/loader.conf hint.p4tcc.0.disabled=3D1 hint.acpi_throttle.0.disabled=3D1 # dmesg | head -n 13 | tail -n 9 FreeBSD 9.0-STABLE #0 r233000M: Thu Mar 15 12:30:27 CET 2012 root@zozo.afpicl.lan:/usr/obj/usr/src/sys/CORE amd64 CPU: Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz (2793.04-MHz K8-class = CPU) Origin =3D "GenuineIntel" Id =3D 0x106e5 Family =3D 6 Model =3D 1e St= epping =3D 5 Features=3D0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PG= E,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> Features2=3D0x98e3fd<SSE3,DTES64,MON,DS_CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xT= PR,PDCM,SSE4.1,SSE4.2,POPCNT> AMD Features=3D0x28100800<SYSCALL,NX,RDTSCP,LM> AMD Features2=3D0x1<LAHF> TSC: P-state invariant, performance statistics I tried with and without powerd and there's no noticeable difference, so I don't use it. I also tried with and without performance_cpu_freq=3D"HIGH" in /etc/rc.conf (without, dev.cpu.0.freq is 2799 so I don't think TurboBoost is enabled in this case). > If it is due to the system hanging, it is almost certainly because you > have throttling enabled. Throttling, either by the use of TCC (also > called P4TCC) or the older, externally implemented throttling > mechanism, is a BAD BAD THING! I have complained for years about it > being the default. It is intended for thermal control, not power > management. The power savings will be negligible and, in combination > with deep sleep modes (Cx > 2) can and do result in the CPU going into > deep sleep and never waking up. > > You can (and should) disable them in /boot/loader.conf with: > # Disable CPU throttling > hint.p4tcc.0.disabled=3D1 > hint.acpi_throttle.0.disabled=3D1 > > This should greatly reduce the large number of "frequencies" > available, but they will be the ones provided by EST.which really do > reduce power consumption. (I put frequencies in quotation marks > because throttling does not really change the clock speed. It simply > skips 'N' of every 8 clock cycles. Still, compared to C3 and higher, > EST is a minor power savings. > > Just following the recommendations on the power management web page is > the way to go. > -- > R. Kevin Oberman, Network Engineer > E-mail: kob6558@gmail.com > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" --=20 Olivier Smedts=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=A0 _ =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 ASCII ribbon campaign ( ) e-mail: olivier@gid0.org=A0 =A0 =A0 =A0 - against HTML email & vCards=A0 X www: http://www.gid0.org=A0 =A0 - against proprietary attachments / \ =A0 "Il y a seulement 10 sortes de gens dans le monde : =A0 ceux qui comprennent le binaire, =A0 et ceux qui ne le comprennent pas."
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