Hi, I have an overclocked i7 920 CPU for which I have enabled Turbo Mode in the BIOS (21x multiplier). The base clock is set at 190 MHz, so the CPU frequency with Turbo mode activated should be 3990 MHz. However the maximum value FreeBSD amd64 shows for the CPU frequency in dmesg and sysctl is 3790 MHz. How can I enable the Turbo Mode? CPU: Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz (3790.52-MHz K8-class CPU) machdep.acpi_timer_freq: 3579545 machdep.tsc_freq: 3790522507 machdep.i8254_freq: 1193182 dev.cpu.0.freq: 349 dev.cpu.0.freq_levels: 2793/130000 2443/113750 2094/97500 1745/81250 1396/65000 1047/48750 698/32500 349/16250 Thanks!
Pierre-Luc Drouin wrote:> I have an overclocked i7 920 CPU for which I have enabled Turbo Mode in > the BIOS (21x multiplier). The base clock is set at 190 MHz, so the CPU > frequency with Turbo mode activated should be 3990 MHz. However the > maximum value FreeBSD amd64 shows for the CPU frequency in dmesg and > sysctl is 3790 MHz. How can I enable the Turbo Mode?The turbo mode doesn't show up in dmesg or sysctl, it dynamically overclocks inside the CPU. Also, some motherboards silently disable turbo mode when you overclock the base clock. You may need to use a benchmark running on 1 vs 4 cores to see if turbo mode is having any effect. - Andrew
On Thu, 10 Sep 2009 20:57:32 -0400 Pierre-Luc Drouin <pldrouin@pldrouin.net> wrote:> Hi, > > I have an overclocked i7 920 CPU for which I have enabled Turbo Mode > in the BIOS (21x multiplier). The base clock is set at 190 MHz, so > the CPU frequency with Turbo mode activated should be 3990 MHz. > However the maximum value FreeBSD amd64 shows for the CPU frequency > in dmesg and sysctl is 3790 MHz. How can I enable the Turbo Mode? > > CPU: Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz (3790.52-MHz > K8-class CPU) > > machdep.acpi_timer_freq: 3579545 > machdep.tsc_freq: 3790522507 > machdep.i8254_freq: 1193182 > dev.cpu.0.freq: 349 > dev.cpu.0.freq_levels: 2793/130000 2443/113750 2094/97500 1745/81250 > 1396/65000 1047/48750 698/32500 349/16250You may be able to use the cpuctl kernel module with sysutils/x86info to see when the CPUs are using Turbo mode. I haven't had any success yet but I know in Windows the System control panel reported the 2.66GHz CPU running at 2.83GHz without me doing anything, so I guess FreeBSD should be doing the same. -- Bruce Cran
On Thursday 10 September 2009 8:57:32 pm Pierre-Luc Drouin wrote:> Hi, > > I have an overclocked i7 920 CPU for which I have enabled Turbo Mode in > the BIOS (21x multiplier). The base clock is set at 190 MHz, so the CPU > frequency with Turbo mode activated should be 3990 MHz. However the > maximum value FreeBSD amd64 shows for the CPU frequency in dmesg and > sysctl is 3790 MHz. How can I enable the Turbo Mode? > > CPU: Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz (3790.52-MHz > K8-class CPU) > > machdep.acpi_timer_freq: 3579545 > machdep.tsc_freq: 3790522507 > machdep.i8254_freq: 1193182 > dev.cpu.0.freq: 349 > dev.cpu.0.freq_levels: 2793/130000 2443/113750 2094/97500 1745/81250 > 1396/65000 1047/48750 698/32500 349/16250You have to enable C2/C3 sleep states (possibly in your BIOS). However, FreeBSD doesn't currently handle this but so well since that will probably turn off the local APIC timer interrupt when the CPU is idle causing FreeBSD to miss clock interrupts. -- John Baldwin