Memory Profiling Overhead
Product Overview
I/O is either performed at the end of the execution or when the end-user decides
(please refer to Coverage Snapshots in the documentation).
As a summary, Hit Count mode and modified/multiple conditions produce the
greatest data and execution time overhead. In most cases you can select each
coverage type independently and use Pass mode by default in order to reduce this
overhead. The source code can also be partially instrumented.
Memory and Performance Profiling and Runtime Tracing
Any source file containing an instrumented routine receives a declaration for a 16
byte structure.
Within each instrumented routine, a
n
byte structure is locally declared, where
n
is:
·
16 bytes
·
+4 bytes for Runtime Tracing
·
+4 bytes for Memory Profiling
·
+3*
t
bytes for Performance Profiling, where
t
is the size of the type returned by
the clock-retrieving function
For example, if
t
is 4 bytes, each instrumented routine is increased of:
·
20 bytes for Memory Profiling only
·
20 bytes for Runtime Tracing only
·
28 bytes for Performance Profiling only
·
36 bytes for all Runtime Analysis features together
Memory Profiling Overhead
This applies to Memory Profiling for C and C++. Memory Profiling for Java does not
use source code insertion.
Any call to an allocation function is replaced by a call to the Memory Profiling
Library. See the Target Deployment Guide for more information.
These calls aim to track allocated blocks of memory. For each memory block, 16+12*
n
bytes are allocated to contain a reference to it, as well as to contain link references
and the call stack observed at allocation time.
n
depends on the Call Stack Size
Setting, which is 6 by default.
If ABWL errors are to be detected, the size of each tracked, allocated block is
increased by 2*
s
bytes where
s
is the Red Zone Size Setting (16 by default).
If FFM or FMWL errors are to be detected, a Free Queue is created whose size
depends on the Free Queue Length and Free Queue Size Settings. Queue Length is
the maximum number of tracked memory blocks in the queue. Queue Size is the
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