Methods and arrangements for collecting tracing data from a plurality of
threads of a program. A storage buffer is provided, a first number of
units of tracing data for a first thread of the program is determined,
and a second number of units of tracing data for a second thread of the
program is determined. In the storage buffer, a first block of storage
space is reserved for storing the first number of units of tracing data
and a second block of storage space is reserved for storing the second
number of units of tracing data. Tracing data are thence written
concurrently into the first and blocks.