Qprof environment variables
	---------------------------

QPROF_REAL		- Use real-time for profiling.
QPROF_VIRTUAL		- Use virtual (user mode) time for profiling.
QPROF_INTERVAL		- Microseconds or events between profiling ticks.
			  Default 10,000 usecs or 10,000 events.
QPROF_BUFFER_SIZE	- Size of PC sample buffer in entries.  Default 400K.
QPROF_GRANULARITY	- Set to "instruction", "line", or "function".
			  Default is "function".
QPROF_ADDR2LINE		- Path of addr2line command.
			  Default /usr/bin/addr2line.
QPROF_NCOLS		- Number of columns in qprof output.  May need to
			  be adjusted if long function names are common.
QPROF_HW_EVENT		- Can be set to the name of a hardware event counter
			  to base profile sampling on that event.  Currently
			  this is functional only on Linux/Itanium, and only
			  if perfmon/libpfm are installed.  Requires that
			  qprof be built with -DHW_EVENT_SUPPORT. Try
			  "pfmon -l" to see a list of possible events.
QPROF_FILE		- Specifies the name of a file to be used for profiling
			  output instead of stderr.
QPROF_COLOR		- Specifies an ECMA 48 character attribute that will
			  be used for profiling output.  This makes sense
			  primarily when the output is being sent directly to
			  a terminal.  In this case it often allows profiling
			  output to be displayed in a different color to
			  distinguish it from other output.
			  Possible values include:
				31	red foreground
				32	green foreground
				34	blue foreground
				43	yellow background
			  The names "red", "green", "blue" are also
			  recognized.  An unrecognized value defaults to
			  34 (blue).
QPROF_STACK		- If set, include all PC values on the call stack
			  when a sample is taken.  Effectively this means
			  that the resulting count associated with each
			  function includes the time spent in its callees.
			  For deep call stacks or slow stack unwinders, this
			  may result in appreciable additional overhead or
			  measurement errors.  This works only if a link
			  to libunwind was found in the source directory
			  during the install process.
Q_DIR			- Directory for q_tools compatible profile
			  information.  If specified and QPROF_FILE is not
			  set, the normal textual profile is suppressed.
QPROF_LOOP_ON_ERROR	- Cause the default error reporting routine to
			  enter an infinite loop.  May facilitate debugging;
			  otherwise not recommended.

LD_PRELOAD 		- Used to invoke profiling library.