Re: lowlatency kernel status?
On 2011-01-27 17:13, Scott Lavender wrote: On Wed, Jan 26, 2011 at 9:25 AM, David Henningsson mailto:david.hennings...@canonical.com>> wrote: What is really the current status of the lowlatency kernel? Are we planning to have it in universe for Natty? If so, is any work going on in that area? Alessio answered most of these questions, however I would like to add a few more comments. Alessio, would you please upload your -lowlatency kernel to the repository since there will be a delay in the documentation? I believe it is paramount to have the -lowlatency kernel in place for user experience and functionality. I also would like to note that a few items about Alessio's kernel that have been explained to me: * it is based on the -generic Ubuntu kernel * it does NOT have an invasive patch as others have declared or believed * changes in build time flags ONLY are required to build Alessio's kernel I apologize if I am being pedantic but sometimes I feel like this is an continually uphill battle, but it is one that I am committed. I talked to Andy Whitcroft yesterday about providing "derivative flavour" documentation, but he is currently busy with other tasks so this documentation will have to wait (no prognosis given). So I assume that waiting on that documentation is not an option. Again, I want to reiterate my desire to get the -lowlatency kernel into the repositories for a Natty release. Given that it is based on the -generic Ubuntu kernel and ONLY requires compile flags I would like to believe that this is possible. Also, do we have any signs of this kernel performing better than the generic one? (As for bug 690010, that's fixed upstream now, and will be fixed in the generic kernel on the next Natty kernel upload.) My experience is that the -lowlatency performs in a far superior manner than the -generic one for audio work. Using my Dell P4, 2.8ghz machine with 3 gigs memory and an MAudio Delta 44 card I test the -generic kernel using JACK and Ardour and made test recordings of guitar. I found that the -generic kernel provided stable performance (i.e. no xruns) at slightly over 22msecs. Using the same machine I installed Alessio's -lowlatency kernel and testing it in the same manner. I found that the -lowlatency kernel provided stable performance (i.e. no xruns) at just under 3msecs. I hope all find this information useful. Thanks, it's the first time I've actually seen some numbers, that's great and could point as confirmation that there is actually a need for this kernel. Would you (and others) mind redoing the test with the 2.6.38-1-generic kernel? It is not yet installed by default, but you can test it with sudo apt-get install linux-image-2.6.38-1-generic (then reboot and choose the right kernel in grub.) And to be fair, I guess it should be tested against a 2.6.38 version of the lowlatency kernel as well. I have confirmed that bug #690010 is fixed in this kernel. -- David Henningsson, Canonical Ltd. http://launchpad.net/~diwic -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
On Thu, Jan 27, 2011 at 12:03 PM, Scott Lavender wrote: > > > On Thu, Jan 27, 2011 at 10:13 AM, Scott Lavender > wrote: > >> My experience is that the -lowlatency performs in a far superior manner >> than the -generic one for audio work. >> >> Using my Dell P4, 2.8ghz machine with 3 gigs memory and an MAudio Delta 44 >> card I test the -generic kernel using JACK and Ardour and made test >> recordings of guitar. I found that the -generic kernel provided stable >> performance (i.e. no xruns) at slightly over 22msecs. >> >> Using the same machine I installed Alessio's -lowlatency kernel and >> testing it in the same manner. I found that the -lowlatency kernel provided >> stable performance (i.e. no xruns) at just under 3msecs. >> >> I hope all find this information useful. >> >> ScottL >> >> >> > I should point out that my the performance experienced with the -generic > kernel suffered from not being able to have real-time privileges presumably > due to the bug mentioned above. > > -- > Ubuntu-Studio-devel mailing list > Ubuntu-Studio-devel@lists.ubuntu.com > Modify settings or unsubscribe at: > https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel > > in lucid, i use the -realtime kernel with my firewire device regularly... i have tested the -lowlatency kernel in both maverick and natty (more in natty) and it seems i can actually push my JACK settings a little more... im not positive this is happening, and there are more variables than kernel involved, but the -lowlatency kernel in natty is at least as good performance wise for me as lucid with -realtime... i use a presonus firepod, and i test with JACK running around 1.2ms latency (not that i need it that low usually)... the generic kernel is a no-go for me using firewire + JACK... i have a pretty strict zero xrun policy, so i cant say i get less xruns, i get 1 or 2 here or there opening an application, but not during normal operation... dont take my word for it though... you can add abogani's ppa easily by reading https://launchpad.net/~abogani/+archive/ppa and running in a terminal sudo add-apt-repository ppa:abogani/ppa then, you can install both linux-realtime and/or linux/lowlatency in natty and see how your hardware works... assuming this is a test install of natty anyways, you are probably not worried about adding PPA's, but http://ubuntu-tweak.com/ has a very nice and easy GUI way to purge PPA's and the PPA's packages from the system that i have used in lucid... IF you get a chance to test, let us know what you find and what hardware you are testing with.. thanks -- MH http://opensourcemusician.libsyn.com/ http://wnclug.ourproject.org/ -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
On Thu, Jan 27, 2011 at 10:13 AM, Scott Lavender wrote: > My experience is that the -lowlatency performs in a far superior manner > than the -generic one for audio work. > > Using my Dell P4, 2.8ghz machine with 3 gigs memory and an MAudio Delta 44 > card I test the -generic kernel using JACK and Ardour and made test > recordings of guitar. I found that the -generic kernel provided stable > performance (i.e. no xruns) at slightly over 22msecs. > > Using the same machine I installed Alessio's -lowlatency kernel and testing > it in the same manner. I found that the -lowlatency kernel provided stable > performance (i.e. no xruns) at just under 3msecs. > > I hope all find this information useful. > > ScottL > > > I should point out that my the performance experienced with the -generic kernel suffered from not being able to have real-time privileges presumably due to the bug mentioned above. -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
On Wed, Jan 26, 2011 at 9:25 AM, David Henningsson < david.hennings...@canonical.com> wrote: > What is really the current status of the lowlatency kernel? Are we planning > to have it in universe for Natty? If so, is any work going on in that area? > Alessio answered most of these questions, however I would like to add a few more comments. Alessio, would you please upload your -lowlatency kernel to the repository since there will be a delay in the documentation? I believe it is paramount to have the -lowlatency kernel in place for user experience and functionality. I also would like to note that a few items about Alessio's kernel that have been explained to me: * it is based on the -generic Ubuntu kernel * it does NOT have an invasive patch as others have declared or believed * changes in build time flags ONLY are required to build Alessio's kernel I apologize if I am being pedantic but sometimes I feel like this is an continually uphill battle, but it is one that I am committed. > > I talked to Andy Whitcroft yesterday about providing "derivative flavour" > documentation, but he is currently busy with other tasks so this > documentation will have to wait (no prognosis given). So I assume that > waiting on that documentation is not an option. > > Again, I want to reiterate my desire to get the -lowlatency kernel into the repositories for a Natty release. Given that it is based on the -generic Ubuntu kernel and ONLY requires compile flags I would like to believe that this is possible. > Also, do we have any signs of this kernel performing better than the > generic one? (As for bug 690010, that's fixed upstream now, and will be > fixed in the generic kernel on the next Natty kernel upload.) > > > My experience is that the -lowlatency performs in a far superior manner than the -generic one for audio work. Using my Dell P4, 2.8ghz machine with 3 gigs memory and an MAudio Delta 44 card I test the -generic kernel using JACK and Ardour and made test recordings of guitar. I found that the -generic kernel provided stable performance (i.e. no xruns) at slightly over 22msecs. Using the same machine I installed Alessio's -lowlatency kernel and testing it in the same manner. I found that the -lowlatency kernel provided stable performance (i.e. no xruns) at just under 3msecs. I hope all find this information useful. ScottL -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
On 2011-01-26 23:52, Tim Cook wrote: On Wed, 2011-01-26 at 16:35 +0100, Alessio Igor Bogani wrote: Also, do we have any signs of this kernel performing better than the generic one? Users (aka Ubuntu Studio developers, testers and users) should say that. Sorry I couldn't provide that certainty. I can say qualitatively that it is significantly better than the generic. I have no idea how to deliver any quantitative results. Are there test banks for this? Can you specify this a little bit - when and how is it better? Lower latency in jack? Fewer xruns? Or something else? -- David Henningsson, Canonical Ltd. http://launchpad.net/~diwic -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
On Wed, 2011-01-26 at 16:35 +0100, Alessio Igor Bogani wrote: > > Also, do we have any signs of this kernel performing better than the generic > > one? > > Users (aka Ubuntu Studio developers, testers and users) should say > that. Sorry I couldn't provide that certainty. I can say qualitatively that it is significantly better than the generic. I have no idea how to deliver any quantitative results. Are there test banks for this? --Tim signature.asc Description: This is a digitally signed message part -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
David, 2011/1/26 David Henningsson : > What is really the current status of the lowlatency kernel? Are we planning > to have it in universe for Natty? If so, is any work going on in that area? It is sync-ed with the generic one. Binaries are available in my PPA (https://launchpad.net/~abogani/+archive/ppa/+packages) and sources are available on Zinc (http://kernel.ubuntu.com/git?p=abogani/ubuntu-natty-lowlatency.git;a=summary). There are implemented a series of hacks to avoid space duplication on archives and for simplify a bit the maintenance. > Also, do we have any signs of this kernel performing better than the generic > one? Users (aka Ubuntu Studio developers, testers and users) should say that. Sorry I couldn't provide that certainty. Ciao, Alessio -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
Re: lowlatency kernel status?
On Wed, Jan 26, 2011 at 10:25 AM, David Henningsson wrote: > What is really the current status of the lowlatency kernel? Are we planning > to have it in universe for Natty? If so, is any work going on in that area? > > I talked to Andy Whitcroft yesterday about providing "derivative flavour" > documentation, but he is currently busy with other tasks so this > documentation will have to wait (no prognosis given). So I assume that > waiting on that documentation is not an option. > > Also, do we have any signs of this kernel performing better than the generic > one? (As for bug 690010, that's fixed upstream now, and will be fixed in the > generic kernel on the next Natty kernel upload.) Good news! David, could you email the list when this fixed -generic is uploaded and we can do some -generic / -lowlatency latency comparisons? Thanks, Ronan -- Ubuntu-Studio-devel mailing list Ubuntu-Studio-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
