fixed/expanded doc

doc/dox/jkqtplotter_usage.dox

@@ -47,11 +47,11 @@
   With simlar code you can also integrate JKQTBasePlotter into your own widgets.
  
  
-  This class is immpleented in a such a way that ^different instances can be used in different parallel threads, i.e. the class is re-entrant. 
+  This class is immpleented in a such a way that different instances can be used in different parallel threads, i.e. the class is re-entrant. 
   There are however access to different cached data is synchronized between all threads (i.e. static internal caches are used), which limmits
   the acheavable parallelization speedup!
   
-  \see See \ref JKQTPlotterMultiThreaded for an example of multi-threaded plotting!
+  See \ref JKQTPlotterMultiThreaded for an example of multi-threaded plotting!
  
  
  

examples/multithreaded/README.md

@@ -89,18 +89,21 @@ The main application in [`multithreaded.cpp`](https://github.com/jkriege2/JKQtPl
 
 This test results in the following numbers (on my AMD Ryzen5 8/16-core laptop):
 
+
+------
 [comment]:RESULTS
 
-<u><b>SERIAL RESULTS:</b></u><br/>runtime, overall = 1719.3ms<br/>single runtimes = (214.8 +/- 277.4) ms<br/>speedup = 1.00x<br/>threads / available = 1 / 16<br/><br/>  
+<u><b>SERIAL RESULTS:</b></u><br/>runtime, overall = 9022.3ms<br/>single runtimes = (1127.6 +/- 773.0) ms<br/>speedup = 1.00x<br/>threads / available = 1 / 16<br/><br/>  
 
 <u><b>PARALLEL RESULTS:</b></u><br/>
-runtime, overall = 649.1ms<br/>single runtimes = (605.2 +/- 81.8) ms<br/>speedup = 7.46x<br/>threads / available = 8 / 16<br/><br/><b>speedup vs. serial = 2.6x</b>
+runtime, overall = 2507.3ms<br/>single runtimes = (2431.4 +/- 91.7) ms<br/>speedup = 7.76x<br/>threads / available = 8 / 16<br/><br/><b>speedup vs. serial = 3.6x</b>
 
 [comment]:RESULTS_END
+------
 
 From this data you can observe:
   - The plotting parallelizes nicely, i.e. the speedup ist >7x on a 8-core-machine. This is the speedup calculated as sum of runtimes of each thread, divided by the runtime of all threads in parallel.
-  - BUT: the speedup of serialized plotting vs. parallel plotting is way smaller: It is only 2-3x. This can be explained by the (significant) overhead due to shared caches (and therefore synchronization) between the plotters. This may be reworked in future!
+  - BUT: the speedup of serialized plotting vs. parallel plotting is way smaller: It is only 2-3x. Also the runtime in each thread is about 3x longer than in the serialized example. This can be explained by the (significant) overhead due to shared caches (and therefore synchronization) between the plotters. This may be reworked in future!
   - The variance in runtimes in the (initial) serial test-run is larger than in the parallel run. This is due to filling of the internal caches during the first plotting!
 .