Operation Costs Measured in CPU Clock Cycles

I have written on the merits of 64-bit vs 32-bit, or on the AMD Bulldozer CPU Architecture Overview. An article in ithare.com gave a very good overview about the relative performance of various CPU operations. Below is the graphic:

Also see the often quoted Agner Fog: Instruction Tables.

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PC overheating

When the CPU is not properly cooled down, then the PC crashes, see below video.

The solution for this particular case: Upgrade the BIOS.

What is generally better: 64-bit or 32-bit?

I was just asked this question and referred to Phoronix: Ubuntu 12.04 LTS: 32-bit vs. 64-bit Performance. Phoronix is this excellent web-site run by Michael Larabel.

Below is a chart from 2012. Not all charts look this astonishing!

AMD Bulldozer CPU Architecture Overview

Architecture per core:

Running CPU/GPU Intensive Jobs on Titan Supercomputer

There is a an INCITE program (HPC Call for Proposals), where one can apply for CPU/GPU intensive jobs, the link is INCITE.

From the FAQ: The INCITE program is open to US- and non-US-based researchers and research organizations needing large allocations of computer time, supporting resources, and data storage to pursue transformational advances in science and engineering.

The machines in question: Mira and Titan.

Counting to Ten on Linux

Very good article on timing CPU bound application.

Random ASCII

I recently discovered a Linux shell script that was running slowly due to an inefficiently implemented loop. This innocent investigation ended up uncovering misleading information from time and a bad interaction between the Linux thread scheduler and its CPU power management algorithms.

View original post 1,944 more words

Computer Cooling

Since using Alpenfoehn Gotthard CPU cooling has improved and the whole PC is more silent. On an otherwise idle PC, just xterm and Chrome running:

$ modprobe it87

$ iostat
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.25    0.00    0.25    0.17    0.00   98.33