Specific Test. The CREAM CE Service The neuGRID project uses intensively the computational dimension of the grid. In production, the regular Computing Element (CE) service was installed, as this is a production ready service from the gLite middleware which was already thoroughly tested and used across several communities. However and since a couple of months, a new service was released in production named CREAM CE (which stands for Computing Resource Execution And Management). The main difference between the regular gLite CE and the new CREAM CE is that the latter can be accessed directly through a well defined web service interface and is much more performant. Of course, CREAM CE can also be accessed through the regular WMS scheduler via the ICE plug-in. In order to measure potential reactivity and ease of use improvements, WP7 therefore decided to test it. Indeed, CREAM CE uses a push notification mechanism to report on events to WMS, whereas the regular CE uses a push mechanism, which has a direct impact on user-perceived performances. As a consequence, xx-xxxx-xxxxxx0.xxxx-x.xxx server from the PoC environment was migrated to CREAM CE and different tests were applied, as listed below: • Direct job submission of 1 simple job: one job was directly submitted to the CREAM service (direct submission is a new functionality introduced by CREAM CE). In this configuration the functionality improvement was quite impressive as almost no overhead was noticed. Indeed, for a simple job that took 10 seconds of actual execution, using the regular gLite CE it took approximately 4 to 5 minutes to see the real job completion (as it takes a long time to report through the gLite CE/WMS architecture). In the case of CREAM CE, the job status was nearly reported in real time to the Information System. • Direct job submission of 1000 simple jobs: This test was useful to appreciate that the CREAM service is very efficient even when overloaded. The memory usage is well managed in the latest version (Note: this is also the case with the gLite CE). • Submission of 1 job through WMS/ICE: Same here, the difference between a gLite CE and CREAM is significant. It is however less reactive than when submitting directly to the CREAM service but instead of having 4 to 5 minutes, the response time is turned down to 15 seconds. Of course, this performance heavily depends on the load of WMS. • Submission of 1000 jobs through WMS/ICE: This was operated to test the ICE plug-in. The first test was not a compl...
Specific Test. The CREAM CE Service 22 6 List of Abbreviations 24 7 Bibliography 25
