Using JDK 8u92 with -XX:+UseG1GC -XX:+UseStringDeduplication -Xms13g -Xmx13g,
several observations were made:

1) During load testing application response times are significantly impacted
(increase to 14 sec response times; normal response times are 1 sec) during
the next time string deduplication runs AFTER a concurrent g1 marking cycle;
further that particular string deduplication takes 14 sec to run.

2) All other string deduplications appear normal with durations in the <0.2
sec range.

3) The impact can be lessened by increasing parallel gc threads however it is
still quite significant (14 sec impact w/16 threads, 3 sec impact w/83
threads).

4) The impact occurs 100% of the time just after a concurrent g1 cycle when
the next string deduplication runs.

When String Deduplication was removed, application response times are normal
throughout the load test even after g1 concurrent cycles.