Workshop
Introduc/ons
and
RISC-‐V
Update
krste@eecs.berkeley.edu
!
http://www.riscv.org!
2
nd
RISC-‐V
Workshop,
Berkeley,
CA
June
29,
2015
Krste
Asanović
Instruc(on
Set
Architectures
don’t
ma4er
Most
of
performance
and
energy
running
soKware
on
a
processor
is
due
to:
▪
Algorithms
▪
Applica/on
code
▪
Compiler
▪
OS/Run/mes
▪
ISA
(Instruc/on
Set
Architecture)
▪
Microarchitecture
(core
+
memory
hierarchy)
▪
Circuit
design
▪
Physical
design
▪
Fabrica/on
process
▪
In
a
system,
there’s
also
displays,
radios,
DC/DC
converters,
sensors,
actuators,
…
2
ISAs
do
ma4er
▪
Most
important
interface
in
computer
system
▪
Large
cost
to
port
and
tune
all
ISA-dependent
parts
of
a
modern
soKware
stack
▪
Large
cost
to
recompile/port/QA
all
supposedly
ISA-independent
parts
of
stack
▪
If
using
proprietary
closed-‐source,
don’t
have
code
▪
If
catch
bit
rot,
no
longer
compile
own
source
code
▪
Lost
your
own
source
code
▪
Most
of
the
cost
of
developing
a
new
chip
is
developing
soKware
for
it
▪
Most
current
large
chips
have
mul/ple
ISAs
3
So…
If
choice
of
ISA
doesn’t
have
much
impact
on
system
energy/
performance,
and
it
costs
a
lot
to
use
different
ones
Why
isn’t
there
a
free,
open
standard
ISA
that
everyone
can
use
for
everything?
4
Open
So8ware/Standards
Work!
Field
Networking
OS
Compilers
Databases
Graphics
Architecture
Standard
Free,
Open
Impl.
Ethernet,
Many
TCP/IP
Posix
C
SQL
OpenGL
-‐-‐
Linux,
FreeBSD
gcc,
LLVM
MySQL,
PostgresSQL
Mesa3D
-‐-‐
Proprietary
Impl.
Many
M/S
Windows
Intel
icc,
ARMcc
Oracle
12C,
M/S
DB2
M/S
DirectX
x86,
ARM
§
Why
not
successful
free
&
open
standards
and
free
&
open
implementa/ons,
like
other
fields?
5
京公网安备 11010802033920号
Copyright © 2005-2024 EEWORLD.com.cn, Inc. All rights reserved
评论