Changes between Version 4 and Version 5 of ClientSched

Timestamp:

Dec 3, 2008, 11:38:46 AM (16 years ago)

Author:

davea

Comment:

--

ClientSched

@@ -1 +1 @@
 = Client scheduling policies =
+
+NOTE: this document is outdated because of development in the 6.4 client
+to handle GPU and multithread apps.
+Changes include:
+
+0) app versions now include avg_ncpus, coprocessor usage, and
+a FLOPS estimate (this defaults to the CPU benchmark,
+but for GPU and multithread apps it will be different).
+This info is sent from the server.
+
+1) Estimating the duration of unstarted jobs:
+jobs are now associated with specific app versions.
+The estimated duration of an unstarted job is the WU's
+FLOP estimate divided by the app version's FLOPS,
+scaled by the duration correction factor.
+
+2) Duration correction factor: this is now based on elapsed time
+(i.e. wall time during which the job has been running) rather than CPU time.
+Yes, this is affected by non-BOINC CPU load; that's as it should be.
+
+3) "CPU efficiency" is no longer maintained; it's subsumed in DCF.
+
+4) Estimating the duration of running jobs:
+this is a weighted average of static and dynamic estimates.
+The dynamic estimate is now based on elapsed time rather than CPU time.
+So if a GPU job has been running for 5 min, is 25% done,
+and has used 1 min of CPU, its dynamic estimate is 20 min (not 4 min).
+
+5) round-robin simulation: this was modified to reflect multi-thread
+and coproc apps (e.g., if the host has 1 GPU, only one coproc app
+can run at a time).
+If CPUs are idle because coprocs are in use,
+don't count it towards CPU shortfall.
+
+6) scheduler_cpus() and enforce_schedule() take coprocs and
+avg_ncpus into account.  They try to keep GPUs busy if possible.
+
+---------------
 
 This document describes three related parts of the BOINC core client: