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GSoc2010 project suggestion: swcryptX
I've been thinking about speeding up crypto following the previous
discussion, and would like to propose offering the following project for
this year's Google Summer of Code:
Abstract: The goal of this project is to provide crypto acceleration by
utilizing multiple CPU cores. The work is to extend the existing
software-only "swcrypto" crypto driver and hook that up with NetBSD's
OpenCrypto framework. Work is expected to make the opencrypto(9)
framework itself MP-safe.
Overview of operation
The opencrypto(9) framework exists to coordinate hardware acceleration in
NetBSD. Applications of the framework can be inside the kernel like the
FAST_IPSEC IPsec implementation, or in userland like OpenSSL with the
"cryptodev" engine. Crypto drivers can be realized in software or in
hardware. Hardware drivers can be used to instruct e.g. the AMD Geode LX's
AES block or a HIFN chip to perform cryptographic operations. Upon system
startup, the crypto drivers at the opencrypto(9) framework, telling what
operations they can perform. When an operation is required later, the
framework will look which crypto device is currently not busy, and offload
the operation to that device. Upon completion, the result is fed back to
The image at  illustrates the components and their interaction.
Offloading the cryptographic requests involves some overhead. Data needs
to be transferred to the hardware and back. On systems with a slow CPU,
this overhead is relatively small compared to the operation speed of the
CPU. On faster CPUs, the overhead becomes more of a burden, making the
benefit of the crypto hardware negligible.
As examples, while a hifn(4) chip can provide worthwhile speedups on
500MHz and 1GHz CPUs, no performance win is experienced on a 2.4GHz CPU.
The communication overhead involves data transfers over a PCI bus, which
is of relatively low speed compared to today's modern CPUs. Preventing the
data transfer is a worthwhile goal. In coordination with today's modern
multi-core CPUs, using one or more CPUs solely for the purpose of crypto
acceleration, a measurable improvement of crypto performance is expected.
At the same time, no special hardware requirements beyond the CPU exist.
This allows turning standard contemporary systems into fast crypto systems
The image at  illustrates the idea of interoperation between a CPU
core that runs the kernel and application codes and three cores that are
dedicated to crypto code.
This is where it gets fishy. ;) The existing opencrypto(4) framework
probably needs to be make MP-aware at the same time, employing proper use
of NetBSD's locking framework. The existing swcrypto(4) needs to be
adjusted for operation on multiple CPUs at the same time. A way to decide
how many CPUs are dedicated to run swcrypto(4) instances. CPUs that run
swcrypto(4) need to be taken out from the usual NetBSD CPU scheduling so
that they are available exclusively for crypto.
In no particular order:
* Know how to build and install a kernel
* Understanding of fine grained SMP and locking
* How to use NetBSD's kernel threads, code-wise
* How to interact with NetBSD's scheduler, code-wise
* Tell the scheduler to pin a specific kernel thread to a specific CPU
* Interaction between applications (IPsec, OpenSSL) with opencrypto(9),
* Interaction of crypto providers with opencrypto(9), code-wise
* Hardware! You won't be able to do this without at least two CPU cores
in your machine. The more the better.
* Benchmarking & a test setup for it
Please follow the NetBSD Project Application/Proposal HowTo if
you're serious to work on this project.
If you have any questions let me know, public discussion should be led
on the tech-crypto@ list.
P.S.: I'm not really in a position to mentor this. Mentors welcome! :)
P.P.S.: This proposal is also available at
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