An Evaluation of PCs for HEP under WindowsNT and Linux

Paper: 362
Session: G (talk)
Speaker: Ogg, Michael, University of Texas, Austin
Keywords: commodity computing, PC operating systems

Title: An Evaluation of PCs for HEP under WindowsNT and Linux

Authors: Michael Athanas, Michael Ogg, Gregory Sharp

Affiliation: University of Florida at Gainesville,
University of Texas at Austin
Cornell University

Collaboration: Nile/CLEO

There have been three significant advances which are allowing Personal
Computers (PCs) to be used in production HEP computing environments at a
fraction of the cost of previous proprietary workstation solutions.

1. The performance of the top end of the PC market (e.g the Pentium Pro)
is not only comparable to mid-range workstations, but is actually
superior to most workstations on the market today.
2. As well as processor performance, the peripherals and bus speeds (PCI)
now match the CPU. In fact, the tremendous growth of 100 Mbps
Fast-Ethernet was driven mostly by the PC market.
3. Operating systems are now available that not only support these
environments, but perhaps more importantly allow code to be ported from
other platforms with minimal effort.

In this talk, we describe the work done, and present performance results, in
porting the Nile system and CLEO software to a farm of PCs running the
WindowsNT and Linux operating systems.

Linux was used as the operating system because it is free and widely
available, POSIX-compliant, open (allowing software and hardware
customization where necessary), familiar (just another Unix), supports a
range of development tools, and has an enormous worldwide support base.
WindowsNT was chosen because of its prevalence in the PC community and of
the advanced commercial development tools available.

The CLEO HEP analysis libraries were ported to both OSs: for WindowsNT we
used MSFortran PS v4.0 and Visual C++ v4.0, for Linux we used g++ v2.7.2 and
g77 v0.5.18. The port to Linux was straightforward. We found the gnu g77
compiler produces significantly higher performance code than translated f2c
code. Although WindowsNT advertises strict POSIX.1 compliance, it is
implemented in an impractical manner - the port required the aid of 3rd
party POSIX libraries. We also report on our experience porting and running
the Electra CORBA toolkit on Linux on top of the Isis communication toolkit.

For both OSs, we report on our evaluation of the detailed performance of a
CLEO physics analysis including local vs. network data access.