VI(1) VI(1)
NAME
vi, ki - instruction simulators
SYNOPSIS
vi [ textfile ]
vi pid
ki [ textfile ]
ki pid
DESCRIPTION
Vi simulates the execution of a MIPS binary in a Plan 9
environment. It has two main uses: as a debugger and as a
statistics gatherer. Programs running under vi execute
about two hundred times slower than normal-but faster than
single stepping under db. Ki is similar to vi but interprets
SPARC binaries. The following discussion refers to vi but
applies to ki as well.
Vi will simulate the execution of a named textfile. It will
also make a copy of an existing process with process id pid
and simulate its continuation.
As a debugger vi offers more complete information than
db(1). Tracing can be performed at the level of instruc-
tions, system calls, or function calls. Vi allows break-
points to be triggered when specified addresses in memory
are accessed. A report of instruction counts, load delay
fills and distribution is produced for each run. Vi simu-
lates the CPU's caches and MMU to assist the optimization of
compilers and programs.
The command interface mirrors the interface to db; see db(1)
for a detailed description. Data formats and addressing are
compatible with db except for disassembly: vi offers only
MIPS (db -mmipsco) mnemonics for machine instructions. Ki
offers both Plan 9 and Sun SPARC formats.
Several extra commands allow extended tracing and printing
of statistics:
$t[0ics]
The t command controls tracing. Zero cancels all trac-
ing options.
i Enable instruction tracing
c Enable call tracing
s Enable system call tracing
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VI(1) VI(1)
$i[itsp]
The i command prints statistics accumulated by all code
run in this session.
i Print instruction counts and frequency.
p Print cycle profile.
t (Vi only) Print TLB and cache statistics.
s Print memory reference, working set and size
statistics.
:b[arwe]
Vi allows breakpoints to be set on any memory location.
These breakpoints monitor when a location is accessed,
read, written, or equals a certain value. For equality
the compared value is the count (see db(1)) supplied to
the command.
SEE ALSO
nm(1), db(1)
BUGS
The code generated by vc and kc are well supported, but some
unusual instructions are unimplemented.
Some Plan 9 system calls such as fork cause simulated traps.
The floating point simulation makes assumptions about the
underlying machine floating point support. The floating
point conversions performed by vi may cause a loss of preci-
sion.
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