The Calibrator (v0.9e), a Cache-Memory and TLB Calibration Tool

1. Introduction
2. The Source Code and how to compile it
3. Binary Executables
4. How to use The Calibrator
5. Sample Output
6. The Calibrated Hardware Database
7. Request for Contributions and Feedback

1. Introduction

• number of cache levels
• for each cache level:
• its size
• its linesize
• its access/miss latency
• main memory access latency
• number of TLB levels
• for each TLB level:
• its capacity (i.e. number of entries)
• the pagesize used
• the TLB miss latency

The Calibrator is a by-product of our work on Main-Memory Databases within the MonetDB project.

The Calibrator is freely available for download and usage, but we kindly ask all users to include a reference to the Calibrator's home page (http://www.cwi.nl/~manegold/Calibrator/) whenever they refer to the Calibrator or publish calibration results.

2. The Source Code and how to compile it

To compile the Calibrator on a Windows-System ('95, '98, 2000, NT),

• get the latest (>=1.0) cygwin binary distribution from here
• open a cygnus window, cd to the Calibrator directory
• compile with:
    gcc -mno-cygwin -DWIN32 calibrator.c -o calibrator.exe -lwinmm

3. Binary Executables

4. How to use The Calibrator

[MHz]

gives the CPU's clock speed in Mega Hertz (MHz).

[size]

gives the amount of memory to be used. [size] should be smaller than the total amount of main memory, but it should be significantly bigger than the maximum cache size expected.
[size] is interpreted as bytes; suffixes "k" ("kilo" = 1024), "M" ("Mega" = 1024²), and "G" ("Giga" = 1024³) may be used.

[filename]

gives the filename for the result files.

5. Sample Output

Calibrator v0.9e
(by Stefan.Manegold@cwi.nl, http://www.cwi.nl/~manegold/)

CPU loop + L1 access:       3.00 ns =   3 cy
             ( delay:     100.17 ns = 100 cy )

caches:
level  size    linesize   miss-latency        replace-time
  1     64 KB   64 bytes    8.42 ns =   8 cy   17.11 ns =  17 cy
  2    320 KB   64 bytes  155.75 ns = 156 cy  146.38 ns = 146 cy

TLBs:
level #entries  pagesize  miss-latency
  1       24       4 KB     5.14 ns =   5 cy 
  2      320       4 KB    25.06 ns =  25 cy 

The main memory access latency is then just the sum of the miss-latencies of all cache levels.

[filename].cache-replace-time.data,
[filename].cache-miss-latency.data,
[filename].TLB-miss-latency.data:

the results of the analysis for the cache system and the TLB, respectively.

[filename].cache-replace-time.gp,
[filename].cache-miss-latency.gp,
[filename].TLB-miss-latency.gp:

gnuplot scripts to visualize the results.

Running
 gnuplot [filename].cache-replace-time.gp
 gnuplot [filename].cache-miss-latency.gp
 gnuplot [filename].TLB-miss-latency.gp
creates the respective files with the plots. By default, these gnuplot scripts generate PostScript files
 [filename].cache-replace-time.ps
 [filename].cache-miss-latency.ps
 [filename].TLB-miss-latency.ps.
By commenting-out the terminal settings for PostScript and un-commenting those for GIF in the .gp files, GIF files
 [filename].cache-replace-time.gif
 [filename].cache-miss-latency.gif
 [filename].TLB-miss-latency.gif
can be created instead.

For Win32 users, there is gnuplot for windows.
Mode of operation:
Unzip the file, and put the directory where the wgnuplot.exe file is in your PATH.
To view the plots you produced with the Calibrator interactively, rather than produce postscript output, uncomment the first two lines the .gp files:
  edit MYMACHINE.cache-replace-time.gp :
  place # in front of: set term ...
  place # in front of: set output ...
(similarly for MYMACHINE.cache-miss-latency.gp and MYMACHINE.TLB-miss-latency.gp ).
Then you can invoke gnuplot:
  c:> wgnuplot
Inside the gnuplot prompt, you go to the directory where your calibortor files are:
  gnuplot> cd "c:\calibrator"
(note the double quotes).
Then load the command file to produce the plots:
  gnuplot> load "MYMACHINE.cache-replace-time.gp"

6. The Calibrated Hardware Database

Thanks to Kai Schmerer of ZDNet.de for providing me with some first result for a Pentium 4/1500 with Rambus as well as for an Athlon/1000 with DDR-SDRAM.

7. Request for Contributions and Feedback

Of course, the same holds for anyone having (access to) a Pentium 4. I'd really like to know how the Pentium 4's caches compare to those of a PentiumIII or Athlon...

Stefan Manegold (Stefan.Manegold@cwi.nl)