Ubuntu 7.10 was released today. You can get it from one of the official mirrors or from our unofficial mirror. Notable new features include:
- Improved support for multiple monitors, rotatable monitors, etc.
- Plug and play printer detection
- NTFS writing support out-of-box
- Kernel "dynamic ticks", meaning that the kernel doesn't have to wake up 1000 times per second any more, thus saving power.
- Full or partial hard disk encryption selectable at install time
Okay, this still isn't "research" news, but I like it.
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The EPA has issued its report on data center energy consumption.
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By way of Ars Technica, we find that Citrix (whose software provides virtual Windows desktop environments accessible anywhere, among other things) has purchased XenSource, the commercial arm of the Xen hypervisor virtualization project. Hopefully they'll make it less of a pain to use and deploy Xen.
Also, VMware went public last Tuesday with a successful IPO. Hopefully they'll keep putting out non-commercial freeware like VMware server and player. Maybe we'll some day seen a free (but likely crippled) version of ESX?
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By way of slashdot, we find that the Linux kernel (2.6.23 and up) now sports three virtualization techniques out-of-box: KVM, Xen (just merged), and Lguest (also recently merged).
Lguest in particular looks interesting, as it doesn't require virtualization hardware support (like KVM), but is as simple as a single modprobe (as opposed to the Xen behemoth). Performance isn't too great right now, though (-30%).
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This Ars Technica article spotlights the development of power-aware technologies at the chip, system, network, and data center levels. It analyzes recent developments in terms of granularity, i.e. the frequency of reaction. Overall, a well written article.
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This article talks about the performance issues on multi-core system. It basically recommends to use the parallelism, such as OpenMP, in order to take full advantage of it. It also gives the common issues limiting the performance. I think it's a very good article to summarize idea.
http://www.devx.com/go-parallel/Article/34428
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Here are the paper list proposing research using the OpenMP library in Power-aware computing area.
1. Chun Liu, et. al, "Exploiting Barriers to Optimize Power Consumption of CMPs", IPDPS 2005.
This work is to use slack time among processors. By figuring out stall time at the end of each iteration, it reduces the frequency to save power without performance degradation. The evaluation in th paper is done only with simulator, not real experiment. SpecOMP is used to verify the idea.
2. Matthew Curtis-Maury, et. al, "Online Power-Performance Adaptation of Multithreaded Programs using Hardware Event-Based Prediction", ICS 2006.
This paper designed and implemented a framework that can adaptively regulate the concurrency level during program execution. So, the processors/threads configuration is changed based to achieve near-optimal energy efficiency. It build power/performance models and uses the hardware counters. For evaluation, 4 hyperthreaded Intel processors are used.
3. Jian Li, et. al, "Dynamic Power-Performance Adaptation of Parallel Computation on Chip Multiprocessors", HPCA 2006.
This paper proposes a heuristic method to determine # of processors and frequency level on one CMP node. All evaluation are performed on simulator. It does not expand the approach to multiple CMP nodes.
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This presentation file explains why the hybrid of MPI/OpenMP programming is required.
It comes with the examples and strategies.
Also, it talks about when the hybrid mode performs better.
http://www.nersc.gov/nusers/services/tr ... hybrid.ppt
Also, here are the paper list focusing on the performance in hybrid MPI/OpenMP applications.
1. Felix Wolf, et. al, "Automatic performance anlysis of hybrid MPI/OpenMP applications", Journal of Systems Architecture 2003.
2. Laksono Adhianto, et. al, "Performance Modeling of Communication and Computation in Hybrid MPI/OpenMP applications", ICPADS 2006.
3. Edmond Chow, et. al, "Assessing Performance of Hybrid MPI/OpenMP Programs on SMP Clusters"
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The ext3cow file system has been released for the 2.6 Linux kernel. This extension to ext3 adds "copy on write" (cow) functionality, which in turn allows the user to view the file system as it existed in the past. Unlike fixed checkpointing, this means that a user could dial in any time whatsoever, and see a consistent filesystem from that moment. It would be interesting to see what the performance characteristics of the system are.
If you're interested, you can get it from ext3cow.com; it consists of a kernel patch based on kernel 2.6.20.3, as well as some userland tools.
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Three tenured professors were having a dialogue. The first argued that it is wrong to kill sheep because they provide us with milk and wool. The second argued that it is wrong to kill cows because they provide us with milk and plow our fields. The third argued that it is wrong to kill pigs because they provide us with bacon, ham, and pork chops.
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