Re: How should I debug or adobt better data processing for high speed
"Electronic75" <Electronic75@discussions.microsoft.com> wrote in message
news:A0BE6B25-4A34-4C81-AFCC-78B44F95F3CB@microsoft.com...
Hello! I have a program in MFC that collects data via USB, process it and
display graphs. When data rate is relatively low(max. 1K bytes/Sec) the
program works Ok but when data speed exceeds 10K bytes/Sec program goes
crazy
after a while and shows fictionally data .
One can only guess. But data corruption at "high speeds" suggests
synchronization problems between threads. The faster it goes the higher the
probability that it will encounter invalid data states between threads.
BTW, 10Kbyres/sec is not fast. I hive similar apps displaying graphs of
MBytes/sec.
What you might consider is the elimination of the critical section. The
producer thread allocates a 'new' heap buffer for every block of data, and
passes its pointer via a PostMessage. The producer thread never again
touches that buffer and pointer. The consumer thread gets the pointer in a
message handler, processes the data appropriately, then 'delete's the
pointer. This gives you interthread block data transfer (and queueing) with
absolute thread safety and no need to think about synchronization.
You also mentioned that you update some volatile variables, without further
explanation. If you think that makes the updates thread safe you are
mistaken.
--
Scott McPhillips [VC++ MVP]