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SUMMARY:Hybrid binary rewriting for memory access instrumentation - Amitab
 ha Roy (University of Cambridge)
DTSTART:20110505T150000Z
DTEND:20110505T160000Z
UID:TALK30749@talks.cam.ac.uk
CONTACT:Eiko Yoneki
DESCRIPTION:Memory access instrumentation is fundamental to many applicati
 ons such as software transactional memory systems\, profiling tools and ra
 ce detectors. In this talk I present a technique to efficiently instrument
  memory accesses in x86 machine code to support software transactional mem
 ory and profiling.  The two primary options in building such an instrument
 ation system are static and dynamic binary\nrewriting: the former instrume
 nts binaries at link time before execution\, while the latter binary rewri
 ting instruments binaries at runtime. Static binary rewriting offers extre
 mely low overhead but is hampered by the limits of static analysis. Dynami
 c binary rewriting is able to use runtime information but typically incurs
  higher overhead.\nIn this talk I discuss an alternative: hybrid binary re
 writing. Hybrid binary rewriting is built around the idea of a persistent 
 instrumentation cache (PIC) that is associated with a binary and contains 
 instrumented code from it. It supports two execution modes when using inst
 rumentation: active and passive modes. In the active execution mode\, a dy
 namic binary rewriting engine (PIN) is used to intercept execution\, and g
 enerate instrumentation into the PIC\, which is an on-disk file. This exec
 ution mode can take full advantage of runtime information. Later\, passive
  execution can be used where instrumented code is executed out of the PIC 
 and uninstrumented code directly from the native binary\, leading to overh
 eads similar to that of static binary rewriting.\n
LOCATION:SS03\, Computer Laboratory\, William Gates Builiding
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