Mention again that pheft tries varying combined worker sizes

doc/chapters/advanced-examples.texi

@@ -924,7 +924,9 @@ The solution is then to use only one combined worker at a time.  This can be
 done by setting @code{single_combined_worker} to 1 in the @code{starpu_conf}
 structure, or setting the @code{STARPU_SINGLE_COMBINED_WORKER} environment
 variable to 1. StarPU will then run only one parallel task at a time (but other
-CPU and GPU tasks are not affected and can be run concurrently)
+CPU and GPU tasks are not affected and can be run concurrently). The parallel
+task scheduler will however still however still try varying combined worker
+sizes to look for the most efficient ones.
 
 @node Debugging
 @section Debugging

doc/chapters/basic-api.texi

@@ -139,7 +139,9 @@ By default, StarPU executes parallel tasks concurrently.
 Some parallel libraries (e.g. most OpenMP implementations) however do
 not support concurrent calls to parallel code. In such case, setting this flag
 makes StarPU only start one parallel task at a time (but other
-CPU and GPU tasks are not affected and can be run concurrently).
+CPU and GPU tasks are not affected and can be run concurrently). The parallel
+task scheduler will however still however still try varying combined worker
+sizes to look for the most efficient ones.
 This can also be specified with the @code{STARPU_SINGLE_COMBINED_WORKER} environment variable.
 
 @item @code{int disable_asynchronous_copy} (default = 0)