sv6 is a POSIX-like research operating system designed for multicore scalability based on xv6.
sv6 is not a production kernel. Think of it as a playground full of half-baked experiments, dead code, some really cool hacks, and a few great results.
Building and running sv6 in QEMU
make && make qemu
You'll need GCC version 4.7 or later and GNU make.
There are several variables at the top of the top-level
may want to override for your build environment. It is recommended
you set them in
The kernel is configured via
param.h. If you're just running sv6 in
QEMU, you don't have to modify
param.h, but you may want to read
The most important
Makefile variable is
HW. This controls the
hardware target you're building for and affects many settings both in
param.h. The default
qemu. Each of
our multicore machines also has a
HW target (like
ben), and other interesting
HW targets are mentioned below.
Builds go to
panic: unhandled inode 369 type 0 on boot: This seems to be a bug in
the virtual IDE controller of some versions of QEMU (though we're not
positive). Try upgrading (or downgrading) QEMU.
Running sv6 on real hardware
Make sure you can build and boot sv6 in QEMU first.
Start by adding a
HW target to
param.h using one of the "physical
hardware targets" in
param.h as a template.
HW targets where
MEMIDE is defined to
1 (the default), the
file system image is baked directly into the kernel image. This makes
it possible to boot a physical machine into the sv6 kernel with
nothing but the kernel image itself, and without having to worry about
messing up your disks.
The kernel image is
o.$HW/kernel.elf. This file is
multiboot-complaint, so both GRUB and SYSLINUX can boot it directly.
You can also PXE boot this image over the network using PXELINUX
(that's what we do).
To enable networking support, you'll need to clone lwIP. From the root of your sv6 clone,
git clone git://git.savannah.nongnu.org/lwip.git (cd lwip && git checkout DEVEL-1_4_1 && patch -p1 < ../lwip.patch) make clean
(If you are building another hardware target, be sure to set
sv6 can be run under an mtrace-enabled QEMU to monitor and analyze its memory access behavior. You'll need to build and install mtrace:
git clone https://github.com/aclements/mtrace.git
And build with
HW=mtrace. If mtrace isn't cloned next to the sv6
repository, then set
config.mk to the directory
To run under mtrace,
sv6 is known to run on five machines: QEMU, a 4 core Intel Core2, a 16 core AMD Opteron 8350, 48 core AMD Opteron 8431, and an 80 core Intel Xeon E7-8870. Given the range of these machines, we're optimistic about sv6's ability to run on other hardware. sv6 supports both xAPIC- and x2APIC-based architectures.
For networking, sv6 supports several models of the Intel E1000,
including both PCI and PCI-E models. If you have an E1000, you'll
probably have to add your specific model number to the table in
kernel/e1000.cc, but you probably won't have to do anything else.
Running sv6 user-space in Linux
Much of the sv6 user-space can also be compiled for and run in Linux
make HW=linux. This will place Linux-compatible binaries in
You can also boot a Linux kernel into a pure sv6 user-space!
make HW=linux also builds
o.linux/initramfs, which is a Linux initramfs
file system containing an sv6 init, sh, ls, and everything else. You
can boot this on a real machine, or run a super-lightweight Linux VM
in QEMU using
make HW=linux KERN=path/to/Linux/bzImage/or/vmlinuz qemu
sv6 supports NMI-based system-wide hardware performance counter profiling on both Intel and AMD CPUs. On recent Intel CPUs, it also supports PEBS precise event sampling and memory load latency profiling.
To profile a command, use the
perf tool. E.g.,
perf mailbench -a all / 1
perf monitors unhalted CPU cycles, but other events can
be selected from those known to
perf has run, the sampler data can be read from
To transfer the file to your computer where it can be decoded, use the
curl http://<hostname>/dev/sampler > sampler
Finally, to decode the sample file, use
./o.$HW/tools/perf-report sampler o.$HW/kernel.elf
To get stack traces from a user binary, pass its unstripped ELF image
o.$HW/bin/ls.unstripped) as the last argument instead of the
The kernel continually maintains a lot of internal statistics counters. To see the changes in these counters over a command, run, e.g.
monkstats mailbench -a all / 1