Next: Game workloads have varying
Up: Game populations
Previous: Game populations
To determine the distribution of on-line game popularity, we analyzed
a nine-month subset of the GameSpy data set described in
Section 2, starting March 1st 2003. Of the games, we
consider only the top 50 games, as the remaining games averaged a
minimal number of players throughout the trace. To average popularity
rankings we first calculated the rank ordering of the games and the
number of players at a given rank for each day. Then we averaged
these daily rankings over the nine-month period to show the
distribution of players across the games regardless of fluctuations in
individual game popularity. Figure 6 shows the
popularity data on a log-log scale. As the figure shows, this
distribution is heavily skewed in favor of the most popular games,
with the first ranked game having over ten times the number of players
of the next most popular. This distribution of popularity is most
similar to a power-law distribution. Power-law distributions are of
the form
and occur in a number of places including
the frequency of words in the English language, the popularity of web
pages, and the population of cities. An intuition for these
distributions is that whenever choices are made between many options,
and each choice affects other choices, the choices tend to pile up on
a few popular selections. Games and servers create communities: in
selecting one, each player's choice affects and is affected by the
popularity and reputation of that game or server. A perfect power-law
distribution would graph as a straight line on a logarithmic scale in
both the and axis. The relatively straight line (correlation
coefficient -0.98 for a simple linear regression) demonstrates that
the GameSpy data does follow a power law distribution. This
distribution has an interesting, albeit unfortunate, implication for
provisioning server resources for on-line games: the host must plan
for several orders of magnitude of change in popularity (and therefore
resources) in either direction. As a result, this indicates that
on-demand infrastructure can significantly reduce the costs and risks
of launching and hosting on-line games.
Next: Game workloads have varying
Up: Game populations
Previous: Game populations
2005-08-10