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| SCHED_DEADLINE v6 released |
| By special contributor cloud on 2012-10-27 01:05:38 |
| A new version of the real-time Linux scheduler called SCHED_DEADLINE has been released on the Linux Kernel Mailing List. For people who missed previous submissions, it consists of a new deadline-based CPU scheduler for the Linux kernel with bandwidth isolation (resource reservation) capabilities. It supports global/clustered multiprocessor scheduling through dynamic task migrations. This new version takes into account previous comments/suggestions and is aligned to the latest mainline kernel. A video about SCHED_DEADLINE is also available on YouTube. |
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| RE[11]: lie-nux at it again. |
| By rklrkl on 2012-10-27 15:00:47 |
|
> a "package manager" denotes a hierarchical file system. Nope, a package manager doesn't denote that. It's a way of resolving package dependencies when a one or more parent packages are installed, removed or updated. It also handles one or more software repositories and can be used for entire OS upgrades. In other words, far superior to Windows Update or Apple's Software Update, both of which only handle MS or Apple products respectively and aren't used for OS updates either. The fact that almost every Linux system has its partitions formatted with a hierarchical file system that packages sit on top of is a full two levels of abstraction away from a package manager. > if you take a walk and re-consider linux again... boring, complicated, un-reliable, pretentious. Not boring at all - particularly with massive choices you get for your desktop environment (instead of one for Mac OS X or maybe two if you're suffering Windows 8) and how you can customise it, which is usually where Linux desktops shine (think Compiz with all its special effects). I bet most Windows and Mac desktops look identically boring, with just the background colour/image changed and a stupidly large number of document icons on the Desktop. Now if "boring" you mean not many commercial games for it, then I might agree, but there is a Linux client for Steam in beta right now, plus more and more games are working under WINE, never mind stuff like indie game houses supporting Linux (Humble Indie Bundle anyone?). As for "complicated", you can pretty do most things by the GUI in Linux now and with things like Ubuntu's Software Centre, installing new packages is actually easier than Windows (I hate Windows myriad of package installers and updaters - it's nasty when every app updates in radically different ways). Linux is one of the most reliable OS'es on the planet - only some of the BSD variants (UNIX again!) can beat it for uptimes. It's pretty rare to get a whole kernel crash nowadays that isn't triggered by some sort of hardware fault. It's why Linux is the only OS used for tiny embedded systems (watches, phones etc), through to larger consumer products (hard disk recorders, TVs, wireless routers) right through to servers and mainframes (the most popular OS on the Top 500 supercomputers? Linux). I'm not sure how "pretentious" is an accusation you can level at Linux - I think Apple have that moniker well and truly sewn up. I've found Mac OS X to be a rather inferior UNIX to Linux with a shiny (prententious!) desktop layer on top that is no more functional than the average Linux desktop. > try running lie-nux on your next airplane. good luck not "crashing". I believe many airlines use Linux for their in-flight entertainment systems, but I couldn't speak about the more critical flight systems. I wouldn't be surprised if some of those run a hardened/real-time Linux variant to be honest. |
 - Score: 4 |
| RE: lie-nux at it again. |
| By Gullible Jones on 2012-10-27 15:31:08 |
|
There's a little truth to this. Try running $ dd if=/dev/zero of=~/dumpfile bs=4G count=1 on a system with 2 GB of RAM and any amount of swap space; the OS will hang for a long, long time. (If you don't have swap space, the command will fail because you don't have enough memory. But it's not safe to run without swap space... right?) Mind you, Windows is just as bad about this - it just doesn't have tools like dd preinstalled that can easily crash your computer. :) |
| - Score: 2 |
| RE[12]: lie-nux at it again. |
| By MOS6510 on 2012-10-27 15:44:49 |
|
You're picking nice features from a huge range of Linux distributions. Yes, of course Linux can run on much more limited hardware than let's say Windows and it has a number of nice DE/GUIs, but can it run those graphical wonders on limited hardware? IIRC you could run Linux on a 386 with 1 MB, but that rules out KDE, GNOME, XFCE. The Ubuntu tool you mentioned may be very nifty, but what use it is for Slackware users? Or anyone not using a GUI. Package managers may be nice, but not everything is in a repository and even when everything is you can still break the system. Windows and OS X users can't even spell the word 'dependency'. For some reason these "inferior" systems don't have this problem. Sure, Linux can make a great server operating system or a mediocre desktop system that's great for the more technical minded, but often when the positive points of Linux are presented they tend to be picked from various distributions. |
| - Score: 2 |
| RE[2]: lie-nux at it again. |
| By No it isnt on 2012-10-27 16:37:14 |
|
You sure? I get dd: memory exhausted by input buffer of size 4294967296 bytes (4,0 GiB) Lowering to bs=1G, dd will complete without much noticeable slowdown. |
| - Score: 3 |
| RE[9]: lie-nux at it again. |
| By Bill Shooter of Bul on 2012-10-27 17:04:30 |
| Do you understand how much of a troll you are acting like? WereCalf is being very nice in putting up with your nonsensical non sequiturs. It really sounds as if you are projecting some other hurt you have in your life into this pseudo-technical argument ( no offense to werecalf who is being very nice and technical). But seriously, relax. Play some crazy violent video games, have a beer and chill. |
| - Score: 4 |
| RE[10]: lie-nux at it again. |
| By Athlander on 2012-10-27 17:42:20 |
| I don't think sameer is trolling - he's just exhibiting some social attitudes one can find in south Asia. WereCatf challenged him, thereby challenging his masculinity and his place in society, he tried to assert his superiority by spouting some half-baked ideas and failed. |
| - Score: 5 |
| RE[3]: lie-nux at it again. |
| By Gullible Jones on 2012-10-27 17:44:58 |
|
You're right, my mistake. For the Bad Things to happen, bs has to be set to something between physical RAM and total (physical + virtual) memory. That said, I have never seen large writes fail to produce a noticeable slowdown. Not on an HDD anyway, I'm not sure about SSDs. I suspect that slowdowns during big writes are unavoidable on normal-spec desktops. |
| - Score: 2 |
| RE[2]: lie-nux at it again. |
| By Alfman on 2012-10-27 18:30:32 |
|
Gullible Jones, The OP's clearly trolling, but you post an interesting question. "$ dd if=/dev/zero of=~/dumpfile bs=4G count=1" I don't get your result, it says "invalid number" for any value over 2G, probably because it's using a 32bit signed int to represent the size (on a 32 bit system). "Mind you, Windows is just as bad about this - it just doesn't have tools like dd preinstalled that can easily crash your computer." My own opinion is that this is a case of garbage in, garbage out. dd is a powerful tool and was not designed to second guess what the user wanted to do. You've asked it to allocate a huge 4GB buffer, fill that buffer with data from one file, and then write it out to another. If it has enough ram (including swap?) to do that it *will* execute your request as commanded. If it does not have enough ram, it will fail, just as expected. It's not particularly efficient, but it is doing exactly what you asked it to do. Windows behaves the exact same way, which is the correct way. You could use smaller buffers, or use a truncate command to create sparse files. Maybe we could argue that GNU tools are too complicated for normal people to use, but lets not forget that the unix command line is in the domain of power users, most of us don't really want our commands to be dumbed down. "(If you don't have swap space, the command will fail because you don't have enough memory. But it's not safe to run without swap space... right?)" I don't believe in swap ;) Look at it this way, if a system with 2GB ram + 2GB swap is good enough, then a system with 4GB ram + 0 swap should also be good enough. I get that swap space is so cheap that one might as well use it "just in case" or to extend the life of an older system, but personally I prefer to upgrade the ram than rely on swap. Edited 2012-10-27 18:38 UTC |
| - Score: 3 |
| RE[3]: lie-nux at it again. |
| By Gullible Jones on 2012-10-27 18:43:29 |
|
I realize the above is correct behavior... What bothers me is that (by default anyway) is that it can be used by a limited user to create an an effective denial-of-service attack. Stalling or crashing a multiuser system should IMO (ideally) be something that root, and only root, can do. :P OTOH, the presence of tools like dd is why I much prefer Linux to Windows. Experienced users shouldn't have to jump through hoops to do simple things. Edit: re swap, I wish there were a way of hibernating without it. In my experience it is not very helpful, even on low-memory systems. Edited 2012-10-27 18:44 UTC |
| - Score: 3 |
| RE[12]: lie-nux at it again. |
| By MOS6510 on 2012-10-27 18:49:04 |
| QNX is owned by RIM, the makers of the BlackBerry. |
| - Score: 3 |
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