POSIX-like scalable multicore research OS kernel
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.
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
Makefileyou 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 through it.
The most important
HW. This controls the hardware target you're building for and affects many settings both in the
param.h. The default
qemu. Each of our multicore machines also has a
ben), and other interesting
HWtargets are mentioned below. Builds go to
panic: unhandled inode 369 type 0on 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.
Make sure you can build and boot sv6 in QEMU first.
Start by adding a
param.husing one of the "physical hardware targets" in
param.has a template.
MEMIDEis 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.mkto the directory containing
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.
Much of the sv6 user-space can also be compiled for and run in Linux using
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=linuxalso 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 mailbench -a all / 1
perfmonitors unhalted CPU cycles, but other events can be selected from those known to
perfhas run, the sampler data can be read from
/dev/sampler. To transfer the file to your computer where it can be decoded, use the web server:
curl http:///dev/sampler > sampler
Finally, to decode the sample file, use
./o.$HW/tools/perf-report sampler o.$HW/kernel.elf
To get stack traces from a user binary, pass its unstripped ELF image (e.g.,
o.$HW/bin/ls.unstripped) as the last argument instead of the kernel image.
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