Method to display Legacy Access events with an associated Legacy server
Original Publication Date: 1998-Apr-01
Included in the Prior Art Database: 2005-Apr-04
Labadie, E: AUTHOR [+3]
A method for displaying interactions between an instrumented client and an uninstrumented server is disclosed. This allows interactions with legacy servers to be represented graphically.
Method to display Legacy Access events with an associated
A method for
displaying interactions between an instrumented
client and an uninstrumented server is disclosed. This allows
interactions with legacy servers to be represented graphically.
described techniques provide a mechanism for
displaying the interactions between processes in a parallel or
distributed system (1,2) Those techniques assume that instrumentation
is present in all processes, so that event data may be obtained from
all processes during execution.
produced by these techniques consists of horizontal
lines, called event traces, representing processes or threads.
Symbols on those lines represent events of interest. Interactions
between processes or threads are represented by drawing a connecting
line between event symbols on the two event traces.
If a client
that has been instrumented interacts with a server
that has not been instrumented (subsequently referred to as a
"legacy" server), only half of each event pair will be received. A
simple solution can be devised in which short arrows perpendicular to
the "trace line" represent interaction with a process not shown, but
this does not indicate whether different instances represent
interactions with one or several legacy servers and does not indicate
in what order those interactions occurred at the legacy server(s).
invention provides a mechanism for constructing an event
trace corresponding to a legacy server that represents the behavior
of the server as accurately as possible, given the available
information. It assumes that the client-server interactions are
synchronous, as is usually the case. Once the "missing" event traces
have been constructed, a display may be produced using the previously
described techniques, without any further special handling.
solution to be feasible, client instrumentation must
be able to determine (a) whether an event involves interaction with a
legacy server and (b) the identity of a legacy server. Events
reported by client instrumentation must contain these two pieces of
instrumented client reports an event representing an
interaction with a legacy server, it attaches a flag to indicate
this. It also includes the identity of the legacy server involved.
events are not modified, they will cause the
display-drawing code to produce short arrows perpendicular to the
trace line. Normally, a process will be executed that uses
information in these events to build an event trace for the legacy
event traces for legacy servers, the timestamp
algorithm is executed, to assign vector timestamps representing the
partial order of events. It will not be able to assign a timestamp
to an event representing an interaction with a legacy server, since
the two events of a synchronous pair must be timestam...