Reduce overhead/slowdown

[mbeckersys]

Execution of a program is drastically slowed down, determine cause and reduce overhead.

Evidence: stress-ng -c1 --cpu-ops=500:

• standalone: ~2s
• valgrind-nullgrind: ~9s
• valgrind-memcheck: ~31s
• valgrind-ws (--ws-every=1E6): ~227s
• valgrind-ws (--ws-every=1E6) --ws-peak-detect=yes): ~226s

Peak detection overhead seems just fine, but the general overhead is unsatisfying.

[mbeckersys]

• valgrind-ws (--ws-every=1E6): ~101s
• valgrind-ws (--ws-every=1E6 --ws-peak-detect=yes): ~103s