http://elinux.org/index.php?title=Caching_of_information_on_udev&feed=atom&action=history 2013-06-19T21:19:36Z Revision history for this page on the wiki MediaWiki 1.22alpha http://elinux.org/index.php?title=Caching_of_information_on_udev&diff=125864&oldid=prev 2012-05-04T03:02:15Z

<p>‎<span dir="auto"><span class="autocomment">Scope</span></span></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black; text-align: center;">← Older revision</td> <td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 03:02, 4 May 2012</td> </tr><tr><td colspan="2" class="diff-lineno">Line 37:</td> <td colspan="2" class="diff-lineno">Line 37:</td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>== Scope ==</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>== Scope ==</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline"> </del># Implementation: 2 weeks</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Implementation: 2 weeks</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline"> </del># Benchmark creation: 1 week</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Benchmark creation: 1 week</div></td></tr> <tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline"> </del># Adapt to community feedback, tests and upstream: 2 weeks</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div># Adapt to community feedback, tests and upstream: 2 weeks</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>== Comments ==</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>== Comments ==</div></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Project proposals 2012]]</div></td><td class='diff-marker'>&#160;</td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>[[Category:Project proposals 2012]]</div></td></tr> <!-- diff cache key elinux:diff:version:1.11a:oldid:125858:newid:125864 --> </table>

Hisaomunakata http://elinux.org/index.php?title=Caching_of_information_on_udev&diff=125858&oldid=prev 2012-05-04T03:01:16Z

<p>Created page with &quot;; Summary: Caching device information on udev ; Proposer: Lucas De Marchi (lucas.demarchi@profusion.mobi) == Description == Currently udev is the most widely used device manage...&quot;</p> <p><b>New page</b></p><div>; Summary: Caching device information on udev<br /> <br /> ; Proposer: Lucas De Marchi (lucas.demarchi@profusion.mobi)<br /> <br /> == Description ==<br /> Currently udev is the most widely used device manager on Linux. It is<br /> responsible for managing<br /> the /dev entries, and provides several useful actions to be run on<br /> specific occasions.<br /> <br /> Right now udev does device discovery and setup on every boot. But<br /> usually this is not needed, especially on embedded devices where the<br /> hardware will not change over time. One major point of<br /> improvement then in order to speed boot now is to cache the<br /> information used by udev, and providing a way of verifying if this<br /> cache is still valid or if it needs to be re-done.<br /> <br /> Udev has several builtin handlers to address changes in the system, as<br /> reported by the kernel: load modules, find firmware, apply rules to<br /> new devices, etc. The purpose of this project is to add the necessary<br /> infrastructure in udev so these builtin handlers can ask for caching<br /> the information they need and re-play them on next boot. This<br /> infrastructure will be evaluated by applying it to module loading:<br /> instead of probing the bus on every boot to decide we need to load a<br /> certain module, we can load it nonetheless because previous boots<br /> needed them. Later on boot sequence we can verify if they were indeed<br /> needed and cache for next boot.<br /> <br /> This idea has already been discussed with the udev upstream, and<br /> they want to see how performance is improved by having such a cache.<br /> The intention is to implement this cache and create benchmarks for<br /> embedded devices, where usually the hardware is not changed between<br /> reboots.<br /> <br /> == Related work ==<br /> * http://en.wikipedia.org/wiki/Udev<br /> <br /> == Scope ==<br /> # Implementation: 2 weeks<br /> # Benchmark creation: 1 week<br /> # Adapt to community feedback, tests and upstream: 2 weeks<br /> <br /> == Comments ==<br /> <br /> [[Category:Project proposals 2012]]</div>

Hisaomunakata