fix formatting for previous commit;
Adjust entry for linux-DVB support
This commit is contained in:
Luigi Rizzo
parent
4e23ae9366
commit
f08789c7e1
Notes:
svn2git
2020-12-08 03:00:23 +00:00
svn path=/www/; revision=33946
1 changed files with 58 additions and 38 deletions
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@ -15,7 +15,7 @@ Ideas//EN"
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<ideas>
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<cvs:keywords xmlns:cvs="http://www.FreeBSD.org/XML/CVS" version="1.0">
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<cvs:keyword name="freebsd">
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$FreeBSD: www/en/projects/ideas/ideas.xml,v 1.111 2009/03/14 10:18:18 rwatson Exp $
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$FreeBSD: www/en/projects/ideas/ideas.xml,v 1.112 2009/03/15 14:13:43 luigi Exp $
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</cvs:keyword>
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</cvs:keywords>
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@ -556,37 +556,51 @@ these buses to be a subclass of this new base class.</p>
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</desc>
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</idea>
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<idea id="kernel-linuxemu" class="soc">
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<title>Kernel support for linux device drivers</title>
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<idea id="kernel-dvb" class="soc">
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<title>Kernel support for linux DVB device drivers</title>
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<desc>
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<p><strong>Technical contact</strong>: <a href="mailto:luigi@FreeBSD.org">Luigi Rizzo</a></p>
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<p>Recently, a project was started to compile linux device drivers
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on FreeBSD through an in-kernel emulation layer, which
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<p>In early 2007 we started a project was started to support the
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building of linux device drivers on FreeBSD.
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This was done through an in-kernel emulation layer, which
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implements part of the linux kernel API on top of the FreeBSD
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kernel API. The initial implementation was good enough to
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support a few USB webcam drivers, and is documented
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<a
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href="http://info.iet.unipi.it/~luigi/FreeBSD/linux_bsd_kld.html">here</a>.</p>
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href="http://info.iet.unipi.it/~luigi/FreeBSD/linux_bsd_kld.html">here</a>.
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The code is actually available as a port, devel/linux-kmod-compat,
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and a popular driver that uses this infrastructure is
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multimedia/linux-gspca-kmod .
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</p>
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<p>We would like to use a similar approach to add support
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for DVB devices, which are widely supported in Linux
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but not in FreeBSD. In particular we expect the project to provide,
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within the FreeBSD kernel, enough of linux compatibility to build
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the core components of the drivers/media/ linux kernel, and then
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a few device drivers including one for a PCI DVB card (e.g.
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saa7134-based).
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</p>
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<p>The goal of this project is to extend this emulation layer
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to cover more of the linux kernel API. Two areas that need
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further work are the API used by network/communication device drivers (e.g.
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many USB wired and wireless device drivers; telephony cards), and the API used
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by memory-mapped devices and drivers (e.g. analog or DVB video
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acquisition cards, both USB and PCI).</p>
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<p>A Summer of Code applicant would be required to choose a significant set of
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extensions to the existing work (e.g. one of those indicated
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above), and select at least two linux device drivers to be
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ported to FreeBSD using the newly implemented functions.</p>
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<p>Before the start of the project a Summer of Code applicant is expected to
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have studied the above URL and understood the emulation technique
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used, and to have/acquire access to at least some of the hardware
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involved, so that actual functionality tests can be performed
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in addition to the compile tests.</p>
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<p>Before the start of the project, a Summer of Code applicant is expected to
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i) become familiar with the approach used by linux-kmod-compat;
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ii) set up a proper test environment, with a couple of DVB devices
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supported by linux, and a working linux installation so that
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one can compare results;
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iii) become familiar with the architecture of the linux code in
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drivers/media.
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<br/>
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Probably the attention should be focused in PCI devices, because
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at this stage the USB stack is in a transition phase and would
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pose some additional difficulties.
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</p>
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<p>
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Expected results are a working porting infrastructure, a working
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linux-dvb-kmod device driver, and a working application to demonstrate
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that the driver is working as expected. We suggest to look at
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"kaffeine" for which a FreeBSD port already exists.
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</p>
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</desc>
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</idea>
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@ -722,23 +736,20 @@ href="http://info.iet.unipi.it/~luigi/FreeBSD/linux_bsd_kld.html">here</a>.</p>
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</desc>
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</idea>
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<idea id="psched">
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<idea id="psched" class="soc">
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<title>Geom-based Disk Schedulers</title>
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<desc>
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<p><strong>Technical contact</strong>: <a
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href="mailto:luigi@freebsd.org">Luigi Rizzo</a></p>
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<p><strong>References</strong>: <a
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href="http://wiki.freebsd.org/moin.cgi/Hybrid">The Pluggable Disk
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Schedulers SoC project</a>, <a
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href="http://www.happyemi.org/hybrid/">Patches</a></p>
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<p>In a 2005 GSoC project, "Pluggable Disk Schedulers", Emiliano
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Mennucci explored the feasibility of pluggable disk schedulers
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for FreeBSD. The project was successful, but we could not explore
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certain approaches (e.g. "anticipation", where requests are delayed
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hoping that some future ones can served without a seek) due to
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architectural limitations the kernel had at the time.
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<p>
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</p>
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<p>
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Since then, the GEOM infrastructure has become available on FreeBSD
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for interacting with disk I/O requests. GEOM has enabled us to
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work on disk schedulers in a much more flexible way, allowing a
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@ -746,7 +757,8 @@ href="http://info.iet.unipi.it/~luigi/FreeBSD/linux_bsd_kld.html">here</a>.</p>
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Fabio Checconi, we have developed a prototype
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implementation of some anticipatory schedulers, see
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<a href="http://info.iet.unipi.it/~luigi/FreeBSD/#geom_sched">GEOM_SCHED</a>.
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<p>
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</p>
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<p>
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GEOM_SCHED works within the geom layer, i.e. above the device driver
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where queueing of requests may actually occur. The way GEOM_SCHED
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does scheduling is by limiting the number of outstanding requests
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@ -757,18 +769,26 @@ href="http://info.iet.unipi.it/~luigi/FreeBSD/linux_bsd_kld.html">here</a>.</p>
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(as it needs to be replicated in all drivers) but it may be
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an interesting thing to do e.g. for some popular device drivers
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such as ATA.
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<p>
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</p>
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<p>
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The proposed SoC work can address one or more of the following
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aspects:
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i) implement suitable classifiers for
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disk requests; ii) implement techniques for the auto-tuning of
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the scheduler parameters; iii) measure the performance implications
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<ul>
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<li>implement suitable classifiers for disk requests;</li>
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<li>implement techniques for the auto-tuning of
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the scheduler parameters;</li>
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<li>measure the performance implications
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of doing scheduling above the device driver, and possibly design
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and implement a suitable mechanism to push the GEOM_SCHED
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module within the device driver itself.
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<p>
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Ultimately, we expect to end up with a production quality subsystem
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for use in FreeBSD.
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module within the device driver itself.</li>
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</ul>
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Ultimately, we expect to end up with a production quality subsystem
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for use in FreeBSD.
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</p>
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<p><strong>References</strong>: <a
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href="http://wiki.freebsd.org/moin.cgi/Hybrid">The Pluggable Disk
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Schedulers SoC project</a>, <a
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href="http://www.happyemi.org/hybrid/">Patches</a></p>
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<p><strong>Requirements</strong>:</p>
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<ul>
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