<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><span style="font-family: PingFangHK-Ultralight;" class="">Hello Björn,</span><div class="" style="font-family: PingFangHK-Ultralight;"><br class=""></div><div class="" style="font-family: PingFangHK-Ultralight;">thank you very much for your quick response. So, if I understand correctly, currently LITMUS-RT does not include any energy-aware scheduler but, <b class="">is it possible to extend the already existing schedulers in LITMUS-RT with <u class="">DVFS</u> and <u class="">sleep states</u> functionality? </b>Or rather one would need to develop energy-aware RT schedulers for LITMUS-RT from scratch?</div><div class="" style="font-family: PingFangHK-Ultralight;"><br class=""></div><div class="" style="font-family: PingFangHK-Ultralight;">About your comment on CPU hot-plugging, does it mean that LITMUS-RT won't work when turning processors off/on even if the architecture allows sleep states?</div><div class="" style="font-family: PingFangHK-Ultralight;"><br class=""></div><div class="" style="font-family: PingFangHK-Ultralight;">Thanks for clearing my doubts, I'm interested in both partitioned and global approaches, so extending the existing schedulers would save some work. Also, it would be nice to have an already tested platform to start working with.</div><div class="" style="font-family: PingFangHK-Ultralight;"><br class=""></div><div class="" style="font-family: PingFangHK-Ultralight;">Kind regards!</div><div class="" style="font-family: PingFangHK-Ultralight;">David Moncada</div><div class="" style="font-family: PingFangHK-Ultralight;"><br class=""></div><div><blockquote type="cite" class=""><div class="">On Nov 7, 2016, at 1:17 AM, Björn Brandenburg <<a href="mailto:bbbrandenburg@icloud.com" class="">bbbrandenburg@icloud.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">FYI my reply to your email. You should sign up for the mailing list to receive all replies.<div class=""><br class=""></div><div class="">- Björn<br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">Begin forwarded message:</div><br class="Apple-interchange-newline"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, 'Helvetica Neue', Helvetica, sans-serif;" class=""><b class="">From: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">Björn Brandenburg <<a href="mailto:bbb@mpi-sws.org" class="">bbb@mpi-sws.org</a>><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, 'Helvetica Neue', Helvetica, sans-serif;" class=""><b class="">Subject: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class=""><b class="">Re: [LITMUS^RT] power management with litmus-rt</b><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, 'Helvetica Neue', Helvetica, sans-serif;" class=""><b class="">Date: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">7 November 2016 at 08:16:43 GMT+1<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, 'Helvetica Neue', Helvetica, sans-serif;" class=""><b class="">To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class=""><a href="mailto:litmus-dev@lists.litmus-rt.org" class="">litmus-dev@lists.litmus-rt.org</a><br class=""></span></div><br class=""><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">On 7 Nov 2016, at 06:18, David Moncada <<a href="mailto:david_moncada@icloud.com" class="">david_moncada@icloud.com</a>> wrote:<br class=""><div class=""><blockquote type="cite" class=""><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">hello, my name is <b class="">david moncada</b> and i'm currently working on <b class="">energy-aware real-time multiprocessor scheduling</b>...<div class=""><br class=""></div><div class="">i'm looking for a platform in which i can implement energy-aware real-time scheduling algorithms and measure performance. i found your system on the web and, as far as i've read about it, seem to be very complete in terms of real-time scheduling algorithms.</div><div class=""><br class=""></div><div class="">my question is: <b class="">does your system supports in some way processor voltage scaling/sleep states? </b>it if did, it would be a very valuable tool for my work…</div></div></div></blockquote><br class=""></div><div class="">Hi David,</div><div class=""><br class=""></div><div class="">depending on your definition of “support”, LITMUS^RT does or does not support DVS and sleep states.</div><div class=""><br class=""></div><div class="">One the one hand, we do nothing to prevent or interfere with Linux’s native support for DVS and sleep states. So if Linux supports your platform, you can use LITMUS^RT to develop DVS-aware real-time schedulers.</div><div class=""><br class=""></div><div class="">On the other hand, LITMUS^RT currently does not include any DVS-aware schedulers. That is, the included schedulers were developed assuming that processor speeds are constant and that processors are always online. For some schedulers, enabling DVS does not make a big difference (e.g., I assume our P-FP and PSN-EDF plugins will work just fine). For others, I’m not so certain (e.g., PFAIR and GSN-EDF may break or behave in unexpected ways).</div><div class=""><br class=""></div><div class="">LITMUS^RT does not support CPU hot-plugging.</div><div class=""><br class=""></div><div class="">If you end up using LITMUS^RT and would like to contribute patches that add or improve DVS, sleep state, or hot-plugging support, I’d be very happy to consider them. </div><div class=""><br class=""></div><div class="">Best regards,</div><div class="">Björn</div><div class=""><br class=""></div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br class=""></body></html>