cpu-speed

I just bought a nifty MBA 13" Core i7. I'm told the CPU speed varies automatically, and pretty wildly, too. I'd really like to be able to monitor this with a simple app. Are there any Cocoa or C calls to find the current clock speed, without actually affecting it? Edit: I'm OK with answers using Terminal calls, as well as programmatic. Thanks! Yevgeni Try this tool called "Intel Power Gadget". It displays IA frequency and IA power in real time. http://software.intel.com/sites/default/files/article/184535/intel-power-gadget-2.zip You can query the CPU speed easily via sysctl , either by command

I would like to do some microbenchmarks, and try to do them right. Unfortunately dynamic frequency scaling makes benchmarking highly unreliable. Is there a way to programmatically (C++, Windows) find out if dynamic frequency scaling is enabled? If, can this be disabled in a program? Ive tried to just use a warmup phase that uses 100% CPU for a second before the actual benchmark takes place, but this turned out to be not reliable either. UPDATE : Even when I disable SpeedStep in the BIOS, cpu-z shows that the frequency changes between 1995 and 2826 GHz In general, you need to do the following

Paraphrasing from in "Programming Pearls" book (about c language on older machines, since book is from the late 90's): Integer arithmetic operations ( + , - , * ) can take around 10 nano seconds whereas the % operator takes up to 100 nano seconds. Why there is that much difference? How does a modulus operator work internally? Is it same as division ( / ) in terms of time? The modulus/modulo operation is usually understood as the integer equivalent of the remainder operation - a side effect or counterpart to division. Except for some degenerate cases (where the divisor is a power of the

I have developed a high performance Cholesky factorization routine, which should have peak performance at around 10.5 GFLOPs on a single CPU (without hyperthreading). But there is some phenomenon which I don't understand when I test its performance. In my experiment, I measured the performance with increasing matrix dimension N, from 250 up to 10000. In my algorithm I have applied caching (with tuned blocking factor), and data are always accessed with unit stride during computation, so cache performance is optimal; TLB and paging problem are eliminated; I have 8GB available RAM, and the

Here is my cat /proc/cpuinfo output: ... processor : 15 vendor_id : GenuineIntel cpu family : 6 model : 26 model name : Intel(R) Xeon(R) CPU E5520 @ 2.27GHz stepping : 5 cpu MHz : 1600.000 cache size : 8192 KB physical id : 1 siblings : 8 core id : 3 cpu cores : 4 apicid : 23 fpu : yes fpu_exception : yes cpuid level : 11 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic ... bogomips : 4533.56 clflush size : 64 cache_alignment : 64 address sizes : 40 bits physical, 48 bits virtual power management : This machine has two CPUs, each with 4 cores with hyperthreading capability, so the

My Django application is insanely slow, I want to figure out what is taking time : I tried Django-debug-toolbar but was unable to find a panel that can give me the break-up of the load time. My requirements: A stack-trace type output with time of execution for each module called to render the page. I want to realize what part of the whole page rendering process is taking the time ? Also, what part is consuming how much CPU [ MOST IMPORTANT ] ? Can django-debug-toolbar do that ? [ What panel ? ] Any other django-app that can do that ? ppetrid django-debug-toolbar 2.0 By default, django-debug

When I used to program embedded systems and early 8/16-bit PCs (6502, 68K, 8086) I had a pretty good handle on exacly how long (in nanoseconds or microseconds) each instruction took to execute. Depending on family, one (or four) cycles equated to one "memory fetch", and without caches to worry about, you could guess timings based on the number of memory accesses involved. But with modern CPU's, I'm confused. I know they're a lot faster, but I also know that the headline gigahertz speed isn't helpful without knowing how many cycles of that clock are needed for each instruction. So, can anyone