Add instruction counter.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4799 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 11 insertions, 0 deletions

diff --git a/qemu-doc.texi b/qemu-doc.texi
index e8641178db..057b9f6551 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -965,6 +965,17 @@ On M68K this implements the "ColdFire GDB" interface used by libgloss.
 
 Note that this allows guest direct access to the host filesystem,
 so should only be used with trusted guest OS.
+
+@item -icount [N|auto]
+Enable virtual instruction counter.  The virtual cpu will execute one
+instruction every 2^N ns of virtual time.  If @code{auto} is specified
+then the virtual cpu speed will be automatically adjusted to keep virtual
+time within a few seconds of real time.
+
+Note that while this option can give deterministic behavior, it does not
+provide cycle accurate emulation.  Modern CPUs contain superscalar out of
+order cores with complex cache heirachies.  The number of instructions
+executed often has little or no correlation with actual performance.
 @end table
 
 @c man end