http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55354
--- Comment #11 from Konstantin Serebryany <konstantin.s.serebryany at gmail dot com> 2012-11-18 19:59:42 UTC --- The above comment is correct. -fPIE is only applicable if we build libtsan.a and link it statically to the pie executable. This mode however, works pretty well and most our users pay this price for performance. On every memory access tsan touches a few (two or three) extra cache lines. Not using -fPIE makes it touch one extra cache line. Even if that line is in L1, it still has a non-zero cost. We will try to provide benchmark numbers next week.
