Units

Many values in an experiment file are physical quantities, such as a clock speed, an amount of memory or a duration. OpenDC reads these with the units defined in opendc-common (package org.opendc.common.units). A value can be written as a string with a unit:

"coreSpeed": "2.1 GHz",
"memory": { "size": "64 GiB" },
"exportInterval": "1 hours"

A plain number, such as 2100 or "2100", is read in the default unit of its quantity, and OpenDC logs a warning. Writing the unit is clearer and avoids mistakes, especially for durations and energy, where the default units are milliseconds and Joule.

Available units

Quantity	Default unit	Examples	Used for
Duration	millisecond	"500 ms", "30 s", "5 minutes", "1 hours", "2 days", "PT13H"	Task and fragment durations, export interval, checkpoint interval and duration
Frequency	MHz	"800 kHz", "2100 MHz", "2.1 GHz"	CPU and GPU core speed, memory speed, CPU and GPU capacity and usage of tasks
Data size	MiB	"512 MiB", "64 GiB", "100 GB", "1 TiB"	Host memory, GPU memory, memory of tasks
Data rate	Kibps	"10 Gbps", "512 MiBps", "900 GBps"	GPU memory bandwidth
Power	Watt	"400 W", "350 Watts", "50 kW", "1 MW"	Power models, maximum power of a power source, charging speed of a battery
Energy	Joule	"3600 J", "5 MJ", "1 kWh", "100 kWh"	Battery capacity and initial charge
Percentage	ratio	"25%", 0.25	Used inside OpenDC, not in experiment files
Timestamp	ms since the Unix epoch	"2024-01-01T00:00:00Z"	Used inside OpenDC, not in experiment files

Durations can also be written in the ISO-8601 format, such as "PT13H" for 13 hours.

Writing values

• The number can have decimals or an exponent, such as "1.5 GHz" or "128e3 MiB". The space between the number and the unit is optional.
• Units can be written as a symbol or as a word, such as "W", "watt" or "Watts".
• Capital letters matter in some cases:
  • m means milli and M means mega. "2400 mhz" is an error, write "2400 MHz". In the same way, "1 MW" is a megawatt.
  • In durations, m means minutes and ms means milliseconds.
  • In data sizes and data rates, b is a bit and B is a byte. "100 Gb" is 100 gigabits.
• Decimal prefixes (k, M, G, T) are powers of 1000 and binary prefixes (Ki, Mi, Gi, Ti) are powers of 1024. "1 GB" is 1000 MB and "1 GiB" is 1024 MiB.

Values without a unit

Counts, ratios and multipliers, such as coreCount, allocationRatio and multiplier, are plain numbers. A few other plain numbers have a fixed unit, which is given on their page. Examples are the embodied carbon of a battery (kg CO2) and the failure distributions (hours).

The output files also use fixed units, which are listed on the Output pages.