Keywords: class-single-multiple

Next: Acknowledgments Up: Benchmark Previous: USER time vs SYSTEM Contents

## Data rate

Figure: Top: data rate (number of spectra written in file per second) as a function of the number of spectra, for two CLASS output file types. Numbers indicate the number of channels per spectrum. Bottom: data rate as a function of the number of channels per spectrum. Numbers indicate the number of spectra written, and the dashed line a linear decrease of the rate with the number of channels. Left: `NEW` (old file type), right: `SINGLE` (new type).

Finally, one of the main purpose of the new CLASS file types was to increase the data rate to the output file. Fig. shows this rate for the old and new types. We can see (top-left) that, with the old file type, this rate was decreasing when writing more and more spectra, e.g. (with 16384 channels per spectrum) falling from 1300 spectra written per second (for the first thousands of spectra) to 300 when writing the 500,000ths. This is fixed with the new file types: the data rate is constant over the number of spectra written (top-right).

Again on the figure (bottom-right), with the new file types, we can observe that the data rate is allways the same for a given number of channels. For a low number of channels (), we can observe that the USER time has an effect on this rate. But for higher number of channels, the rate is dominated by the SYSTEM time: it decreases linearly with the amount of data written. Typical values are:

- 10,000 spectra per second with 128 channels,
- 1,200 spectra per second with 16,384 channels,
- 20 spectra per second with 1,048,576 channels

Next: Acknowledgments Up: Benchmark Previous: USER time vs SYSTEM Contents