Version 16 (modified by 15 years ago) (diff) | ,
---|
Application planning
Application planning is a mechanism that lets the scheduler decide, using project-supplied logic, whether an application is able to run on a particular host, and if so what resources it will use and how fast it will run. It works as follows.
An app version has an associated plan_class: a character string, possibly empty. The plan class is encoded in the app version's directory name, as used by update_versions.
The scheduler is linked with a function
bool app_plan(SCHEDULER_REQUEST &sreq, char* plan_class, HOST_USAGE&);
The sreq argument contains:
- in sreq.host field, a description of the host's hardware, including:
- In p_vendor and p_model, the processor type
- In p_features, the processor features (e.g., fpu tsc pae nx sse sse2 mmx)
- In m_nbytes, the amount of RAM
- in sreq.global_prefs field, the user's global preferences
- in sreq.coprocs, a list of the hosts's coprocessors.
When called with a particular SCHEDULER_REQUEST and plan class, the function returns true if the host's resources are sufficient for apps of that class. If true, it populates the HOST_USAGE structure:
struct HOST_USAGE { double ncudas; // number of NVIDIA GPUs used double natis; // number of ATI GPUs used double gpu_ram; // max amount of GPU RAM used double avg_ncpus; // avg #CPUs used by app (may be fractional) double max_ncpus; // max #CPUs used (not currently used for anything) double flops; // estimated FLOPS char cmdline[256]; // passed to the app as a cmdline argument; // this can be used, e.g. to control the # of threads used };
When deciding whether to send a job to a host, the scheduler examines all latest-version app_versions for the platform, calls app_plan() for each, and selects the one for which flops is greatest. The client uses flops to estimate job completion times.
If gpu_ram is nonzero, the BOINC client (6.10.25+) won't start the app unless that much RAM is available on the allocated GPU.
You are free to define your own set of plan classes, and to link your own app_plan() function with the scheduler. The BOINC scheduler comes with a default app_plan() (in sched/sched_customize.cpp). This defines the following plan classes:
- mt
- An application that can use anywhere from 1 to 64 threads, and whose speedup with N CPUs is .95N. It is passed a command-line argument --nthreads N.
- cuda
- A CUDA application that requires 254MB of GPU RAM, and that uses .5% as many CPU FLOPS as GPU FLOPS.
- cuda23
- Similar, but requires a driver version supporting CUDA 2.3.
- ati
- ATI GPU with Catalyst 8.12+ and DLLS named amd*
- ati13amd
- ATI GPU with Catalyst 9.1+ and DLLS named amd*
- ati13ati
- ATI GPU with Catalyst 9.1+ and DLLS named ati*
- ati14
- ATI GPU with Catalyst 9.7+ and DLLS named ati*
- nci
- A non-CPU-intensive application that uses 1% of a CPU (this will cause the BOINC client 6.7+ to run it at non-idle priority).
- sse3
- A CPU app that requires the SSE3 CPU feature.