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 application.

    The image at [1] illustrates the components and their interaction.

Limitations

    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.

Proposal

    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
    easily.

    The image at [2] 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.

Implementation Roadmap

    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.

Requirements

    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),
        code-wise
      * 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

Project Applications

    Please follow the NetBSD Project Application/Proposal HowTo[3] 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.

[1] http://www.feyrer.de/NetBSD/images/gsoc2010-swcryptX-1.png
[2] http://www.feyrer.de/NetBSD/images/gsoc2010-swcryptX-2.png
[3] http://www.netbsd.org/contrib/soc-application.html



P.S.: I'm not really in a position to mentor this. Mentors welcome! :)
P.P.S.: This proposal is also available at
         http://www.feyrer.de/NetBSD/gsoc2010-swcryptX.html