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  • Computer is dying--what should I be looking for?

    - by Will
    Okay, I'm a bit knowledgeable with pooters and such, but i'm confused. My computer is dying slowly, and I'm not sure what part is causing this. Computer details: Vista, dell machine, intel Q6600, 2.4 Core Duo (quad core), standard memory and drive (unknown manufacturer). Symptoms: I would best describe the symptoms as memory corruption. After a couple days on, I start getting applications crashing or failing to open for a lack of "resources". Sounds are corrupted. Onscreen text gets corrupted; the characters of text are garbled, not the pixels on the screen. Video memory seems untouched as I haven't seen any misplaced pixels. Recently I've lost files on disk. I've also experienced errors reporting a supposed lack of disk space, even though I have fifty gigs free. There was one point where I couldn't get to the POST when booting up. After I cleaned everything (see next) this hasn't happened. Diagnostic steps: First thing I did was clean the case. There was a lot of dust buildup on heatsinks, so I cleaned all that up. No help. Next, I disconnected and reconnected everything, from power cables to memory (did not reseat cpu). No change. Last, I ran the standard vista memory diagnostics and ran checkdisk. Both reported no errors found. I have not run any POST tests, now that I think about it. I'm at a loss at this point. Disk appears fine, memory too. I'd expect motherboard issues to result in the thing not booting up, yet it does every time. What should I be looking at? What more can I do?

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  • How to fix Windows 7 device removal notification loop

    - by Barry Kelly
    Bit of an odd one this. One of our PCs is getting caught in a loop some time after being turned on, usually after a USB storage device has been attached - sometimes an iPod, sometimes a GPS. Specifically, Windows Explorer starts showing a drive icon and letter (E:, as of right now) for the System partition (the small hidden one at the start of the boot drive). Then, the icon disappears. Then it reappears again. And disappears. It does this very quickly, at what looks like maybe 50 times a second. CPU usage in this loop is also very high; averages about 66%. This machine has an i7 920 CPU, which is quad core with hyperthreading; so this usage rate works out to about 5 100% busy threads, along with whatever normal idle load is (particularly Task Manager itself). Inspecting with Process Explorer shows that the device removal notification infrastructure has gone berserk. The threads in system service processes (i.e. apart from Windows Explorer) which are using all the CPU power relate to device notification. The Disk Management MMC snap-in also fails to run when the loop starts. The only way to break the loop, it seems, is to reboot the machine. Anyone seen anything similar to this, and know of a way to fix it? Machine details: Windows 7 x64, fully patched i7 920, 12GB RAM Intel SSD 80GB (X25-M, I believe; not G2) 2TB 5.2K disk for bulk storage AMD HD 5870 Further hardware details await. I'm going to go through and update all drivers I can find.

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  • Windows Server 2008 R2 grinds to a screeching halt during file copy operations

    - by skolima
    When my Windows Server 2008 R2 machine is performing any large disk operations (copying 10GB files from one drive to another, copying similar file over network, merging HyperV snapshots, compressing large files), performance of the whole machine slows down terribly, everything becomes unresponsive. This is noticeable in any situation when the disk access is large enough not to fit in the cache. Are there any settings available for tuning this behaviour? I can accept slower file transfer if this would give me more responsiveness. System details: Dell Optiflex 960, Core 2 Quad Q9650, 8GB RAM, 2 SATA drives - 320GB (ST3320418AS) and 1TB (ST31000528AS), NCQ active on both, Intel 82564LM-3 Gigabit Ethernet, ATI HD 3450 graphics, Intel ICH10 bridge. We have multiple machines like this, every one is exhibiting the same behaviour. I though this was overkill for a workstation, apparently I was mistaken. Update: I guess I shouldn't have mentioned the HyperV at all. The above configuration is a standard workstation setup at the company I work for, this is not a server of any kind. I have at most 3 virtual machines working, and usually I'm the only person accessing them. Never the less, the slowdown occurs even when no VMs are running. On a Linux machine I'd simply ionice the copy process and I could forget about it, is there any way to manage IO priorities on Windows?

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  • Minecraft server hosting hardware specifications [on hold]

    - by Andrew Wright
    I am planning on purchasing a server to rent off Minecraft game servers, largely to friends. I am planning on purchasing a 128GB RAM server to save on colocation costs (as I am likely to need more than 32GB and would have to rent 2U of space...) I am hoping for some advice about the processing power needed to deal with this level of RAM. The servers will be run in a shared environment on linux in a VM to make backups easier. The server I have in mind is dual CPU. I have been considering at the low end dual Xeon E5-2609V2 Quad-Core 2.5Ghz, and at the high end dual Xeon E5-2650V2 Eight-Core 2.6Ghz. The difference between these is 6.4 GT/s and 8 GT/s and £3000 for the lower spec server, £4300 for the higher spec. I was hoping I could get advice about whether it is worth paying for the extra/higher speed processor or if I would be wasting my money? Thank you for any help - I appreciate that this is not directly related to professional system administration.

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  • Win7 taskbar freezes on startup for about 1-2 mins

    - by Mike
    Running Win7 64-bit for about 4 months now. Never had this problem, didn't install anything new recently. When I boot up I can't do anything in the taskbar, it's frozen for about 1-2 minutes then everything is normal. I can right click on my desktop and move my mouse around. This randomly just started happening a couple days ago after a reboot. I have a 3.2ghz quad, SSD, 4 gig ram, etc. and it usually starts up quickly. After some troubleshooting (including running antivirus and Anti-Malware), it doesn't appear to be software related, but appears to be services related. I can boot up in safe mode and safe mode with networking just fine. I can also boot up normally with all my regular software loading at startup, BUT with all my services turned off. Now the odd part. When I run msconfig to disable all the services at startup and go through ticking them on 5-10 at a time or so and booting up it seems to be somewhat random. Ticking everything on from "Application Experience" halfway down to about "Quality Windows Audio Video Experience" and I can boot without the 1-2 min. freeze. Then I start ticking the stuff below that from a couple of Remote Accesses to Smart Card and Task Scheduler, etc. But the weird part is sometimes it will freeze sometimes it won't. I can't narrow it down. Then if it freezes, I'll boot up in safe mode and turn the ones I just turned on back off and I'll reboot normally but it will freeze again. Which makes no sense because that configuration just worked without freezing just before. I got frustrated enough that I backed up and wiped my hard drive (formatted and everything) and reinstalled Win7 but when I booted up, the freeze happened again. Any ideas? Thanks in advance.

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  • How many iptables block rules is too many

    - by mhost
    We have a server with a Quad-Core AMD Opteron Processor 2378. It acts as our firewall for several servers. I've been asked to block all IPs from China. In a separate network, we have some small VPS machines (256MB and 512MB). I've been asked to block china on those VPS's as well. I've looked online and found lists which requires 4500 block rules. My question is will putting in all 4500 rules be a problem? I know iptables can handle far more rules than that, what I am concerned about is since these are blocks that I don't want to have access to any port, I need to put these rules before any allow. This means all legitimate traffic needs to be compared to all those rules before getting through. Will the traffic be noticeably slower after implementing this? Will those small VPS's be able to handle processing that many rules for every new packet (I'll put an established allow before the blocks)? My question is not How many rules can iptables support?, its about the effect that these rules will have on load and speed. Thanks.

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  • vmware server 64 bit on ubuntu 9.10 64 bit with P2V windows 2003 SBS poor network speed

    - by RobertHC
    configuration is ubuntu 2.6.31-21 64 bit vmware 2.0.2 64 bit last release hardware is core 2 quad with 8GB ram guest is win 2003 server SBS 32 bit Dear friends, we have a converted physical to virtual windows sbs 2003, converted with last converter available nowadays http://www.vmware.com/products/converter/ vCenter converter. Running the P2V 2K3 SBS on vmware server, it does boot fine, but we do note an abnormal CPU activity and a poor lan speed. As attempts we did what follow. We removed all unneeded peripherals, we removed one NIC (phisycal server was 2 nics), we changed the vmx to ged the nic recognized as intel instead than amd, we removed 1 cpu (physical was 2 cpu), we removed anything was reported as failed driver from system events monitor. Nothing to do, no way and funny results. Let's read some tests results. All are made with the same file copied in different source folders. Copying from client side (both directions copy, to/from server) results are i.e. 10 seconds, copying the same files from server side (again from and to server) results are different... from client to server, speed is round about (bit more) 10 seconds, but from server to client direction is slower: double the time. Beeing very fast and launching a simultaneous copy "from server to client"+"from client to server", this made from the server side, results in a stuck traffic... 45 seconds to do the copy. vmware tools are installed and e1000 driver has been updated. With one processor CPU activity is still going up and down but much less than with two. Because of test, we installed win 2k8 STD 64 bit. We repeated all the above tests with exactly the same file result is just one: always 5 seconds (this matches the lan speed) Any idea about this issue is welcome and thank you if any. Kind regards R.

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  • Linux 'top' utility widly inaccurate (more so for multi-CPU/core hardware)?

    - by amn
    Hi all. After using 'top' for long time, albeit basically, I have grown to distrust it's '% CPU' column reports. I have a 8-core (quad core Intel i7 920 with hyperthreading) hardware, and see some wild numbers when running a process that should not use more than 5% overall. top happily reports 50%, and I suspect it is not so. My question is, is it a known fact that it's inaccurate when several CPUs/cores are present? I used 'mpstat' from the 'sysstat' package, and it's showings are much more conservative, certainly within my expectations. I did press '1' for 'top' to switch it to show all the core and us/sy/io stats, but the numbers are substantially higher than with 'mpstat'... I know that my expectations can be unfound as well, but my gut feeling tells me 'top' is wrong! :-) The reason I need to know is because the process I am monitoring only guarantees quality of service with CPU usage "less than 80%" (however vague that sounds), and I need to know how much headroom I have left. It's a streaming server.

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  • Hourly SQL Server 2005 Slowness (Possibly caused by SYSTEM)

    - by Zorlack
    We're trying to diagnose the cause of slowness on our Database server. We're running the latest rev SQL Server 2005 on Windows 2008x64. The behavior that we're seeing is this: We see the SYSTEM process spike one of the CPUs for about 2 minutes, during this time SQL server slows down by a factor of 10. The slowness lasts until SYSTEM is done, then in an hour everything starts again. During these slowdowns disk writes don't spike, paging doesn't spike, the only noticeable precursor we see is that SYSTEM maxes out one of the sixteen (HT)CPUs. Note that this doesn't happen at the top of the hour, it just happens once an hour, and it shifts a bit depending on the length of the incident. At the moment this is causing intermittent slowdowns, but when the server is really busy it can cause Worker Thread starvation. The server is a Dual Quad Dell R710 with 96GB of RAM and RAID10 data/log disks. Has anyone experienced this kind of problem? Does anyone know where we should look? Edit: SQL Server Version is 9.0.4035

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  • Display on secondary video card (Nvidia 8400 GS): horrible refresh, bogs system

    - by minameismud
    This is my work computer, but it's a small shop. We do business software development. The most hardcore thing we create is some web animations with html5 and fancy javascript/css. The base machine is a Dell Precision T3500 - Xeon W3550 (3.07GHz quad), 6GB ram, pair of 500GB harddrives, and Win 7 x64 Enterprise SP1. My primary video card is an ATI FirePro V4800 1GB in a PCIe slot of some speed driving a pair of 23s at 1920x1080 through DisplayPort-HDMI adapters. The secondary card is an NVidia GeForce 8400GS in a PCI slot driving a single 17" at 1280x1024 through DVI. On either of the 23" monitors, windows move smoothly, scroll quickly, and are generally very responsive. On the 17", it's slow, chunky, and when I'm trying to scroll a ton of content, Windows will occasionally suggest I drop to the Windows Basic theme. I've updated drivers for both cards, and I've gotten every Windows update relating to video. Specifically: ATI FirePro Provider: Advanced Micro Devices, Inc Date: 6/22/2014 Version: 13.352.1014.0 NVidia 8400 GS Provider: NVIDIA Date: 7/2/2014 Version: 9.18.13.4052 Unfortunately, new hardware isn't really an option. Is there anything I can do software-wise to speed up the NVidia-driven monitor?

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  • Perfmon % Processor Time vs. task manager's CPU usage

    - by nat
    I'm new to using Perfmon and performance monitoring in general (so go easy on me please ;) I know that Perfmon doesn't have anything exactly like Task Manager's CPU usage display, but I'm trying to figure out how to monitor user's CPU usage via Perfmon in a similar way, and trying to understand the measurements (or how to convert the numbers to get a similar understanding) For example, if in Task Manager, a particular user is consistently using more than 5% CPU, I would want to contact the user about it. I learn best by example, so here is exactly what I'm trying to do, with a specific example: This is for a 32-bit Dual Quad Core Windows 2003 web server (8 CPUs), there are many web sites on the server, each running within their own application pool/worker process ID. Through other research here I learned of a registry change that I made so that the PID shows up with the w3wp process so I can easily identify the site later by cross-referencing it. I set up a counter with the following settings: Process -> % Processor Time -> all instances Here is an example. Say I'm interested in "black line" user in this graph below, as his process is spiking quite high compared to all the other users: (I wasn't allowed to post the image as I'm a new user on this site.. I've uploaded the image to:) http://i35.tinypic.com/106yn8k.jpg So... using this as an example, I see that they have an AVERAGE % PROCESSOR TIME of 23.264 , and have spiked as high as 103.124 So what exactly does this 23.264 number mean to me? Is it similar to an average of Task Manager's CPU reading for this user? Or, since this server has 8 CPUs, should I divide this number by 8? (23.264/8 = 2.9% AVERAGE CPU LOAD?) Thanks in advance.

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  • GPGPU programming with OpenGL ES 2.0

    - by Albus Dumbledore
    I am trying to do some image processing on the GPU, e.g. median, blur, brightness, etc. The general idea is to do something like this framework from GPU Gems 1. I am able to write the GLSL fragment shader for processing the pixels as I've been trying out different things in an effect designer app. I am not sure however how I should do the other part of the task. That is, I'd like to be working on the image in image coords and then outputting the result to a texture. I am aware of the gl_FragCoords variable. As far as I understand it it goes like that: I need to set up a view (an orthographic one maybe?) and a quad in such a way so that the pixel shader would be applied once to each pixel in the image and so that it would be rendering to a texture or something. But how can I achieve that considering there's depth that may make things somewhat awkward to me... I'd be very grateful if anyone could help me with this rather simple task as I am really frustrated with myself. UPDATE It seems I'll have to use an FBO, getting one like this: glBindFramebuffer(...)

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  • Improve Efficiency for This Text Processing Code

    - by johnv
    I am writing a program that counts the number of words in a text file which is already in lowercase and separated by spaces. I want to use a dictionary and only count the word IF it's within the dictionary. The problem is the dictionary is quite large (~100,000 words) and each text document has also ~50,000 words. As such, the codes that I wrote below gets very slow (takes about 15 sec to process one document on a quad i7 machine). I'm wondering if there's something wrong with my coding and if the efficiency of the program can be improved. Thanks so much for your help. Code below: public static string WordCount(string countInput) { string[] keywords = ReadDic(); /* read dictionary txt file*/ /*then reads the main text file*/ Dictionary<string, int> dict = ReadFile(countInput).Split(' ') .Select(c => c) .Where(c => keywords.Contains(c)) .GroupBy(c => c) .Select(g => new { word = g.Key, count = g.Count() }) .OrderBy(g => g.word) .ToDictionary(d => d.word, d => d.count); int s = dict.Sum(e => e.Value); string k = s.ToString(); return k; }

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  • Is it possible that a single-threaded program is executed simultaneously on more than one CPU core?

    - by Wolfgang Plaschg
    When I run a single-threaded program that i have written on my quad core Intel i can see in the Windows Task Manager that actually all four cores of my CPU are more or less active. One core is more active than the other three, but there is also activity on those. There's no other program (besided the OS kernel of course) running that would be plausible for that activitiy. And when I close my program all activity an all cores drops down to nearly zero. All is left is a little "noise" on the cores, so I'm pretty sure all the visible activity comes directly or indirectly (like invoking system routines) from my program. Is it possible that the OS or the cores themselves try to balance some code or execution on all four cores, even it's not a multithreaded program? Do you have any links that documents this technique? Some infos to the program: It's a console app written in Qt, the Task Manager states that only one thread is running. Maybe Qt uses threads, but I don't use signals or slots, nor any GUI. Link to Task Manager screenshot: http://img97.imageshack.us/img97/6403/taskmanager.png This question is language agnostic and not tied to Qt/C++, i just want to know if Windows or Intel do to balance also single-threaded code on all cores. If they do, how does this technique work? All I can think of is, that kernel routines like reading from disk etc. is scheduled on all cores, but this won't improve performance significantly since the code still has to run synchronous to the kernel api calls. EDIT Do you know any tools to do a better analysis of single and/or multi-threaded programs than the poor Windows Task Manager?

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  • What is faster- Java or C# (Or good old C)?

    - by Rexsung
    I'm currently deciding on a platform to build a scientific computational product on, and am deciding on either C#, Java, or plain C with Intels compiler on Core2 Quad CPU's. It's mostly integer arithmetic. My benchmarks so far show Java and C are about on par with each other, and dotNET/C# trails by about 5%- however a number of my coworkers are claiming that dotNET with the right optimizations will beat both of these given enough time for the JIT to do its work. I always assume that the JIT would have done it's job within a few minutes of the app starting (Probably a few seconds in my case, as it's mostly tight loops), so I'm not sure whether to believe them Can anyone shed any light on the situation? Would dotNET beat Java? (Or am I best just sticking with C at this point?). The code is highly multithreaded and data sets are several terabytes in size. Haskell/erlang etc are not options in this case as there is a significant quantity of existing legacy C code that will be ported to the new system, and porting C to Java/C# is a lot simpler than to Haskell or Erlang. (Unless of course these provide a significant speedup). Edit: We are considering moving to C# or Java because they may, in theory, be faster. Every percent we can shave off our processing time saves us tens of thousands of dollars per year. At this point we are just trying to evaluate whether C, Java, or c# would be faster.

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  • Unexpected performance curve from CPython merge sort

    - by vkazanov
    I have implemented a naive merge sorting algorithm in Python. Algorithm and test code is below: import time import random import matplotlib.pyplot as plt import math from collections import deque def sort(unsorted): if len(unsorted) <= 1: return unsorted to_merge = deque(deque([elem]) for elem in unsorted) while len(to_merge) > 1: left = to_merge.popleft() right = to_merge.popleft() to_merge.append(merge(left, right)) return to_merge.pop() def merge(left, right): result = deque() while left or right: if left and right: elem = left.popleft() if left[0] > right[0] else right.popleft() elif not left and right: elem = right.popleft() elif not right and left: elem = left.popleft() result.append(elem) return result LOOP_COUNT = 100 START_N = 1 END_N = 1000 def test(fun, test_data): start = time.clock() for _ in xrange(LOOP_COUNT): fun(test_data) return time.clock() - start def run_test(): timings, elem_nums = [], [] test_data = random.sample(xrange(100000), END_N) for i in xrange(START_N, END_N): loop_test_data = test_data[:i] elapsed = test(sort, loop_test_data) timings.append(elapsed) elem_nums.append(len(loop_test_data)) print "%f s --- %d elems" % (elapsed, len(loop_test_data)) plt.plot(elem_nums, timings) plt.show() run_test() As much as I can see everything is OK and I should get a nice N*logN curve as a result. But the picture differs a bit: Things I've tried to investigate the issue: PyPy. The curve is ok. Disabled the GC using the gc module. Wrong guess. Debug output showed that it doesn't even run until the end of the test. Memory profiling using meliae - nothing special or suspicious. ` I had another implementation (a recursive one using the same merge function), it acts the similar way. The more full test cycles I create - the more "jumps" there are in the curve. So how can this behaviour be explained and - hopefully - fixed? UPD: changed lists to collections.deque UPD2: added the full test code UPD3: I use Python 2.7.1 on a Ubuntu 11.04 OS, using a quad-core 2Hz notebook. I tried to turn of most of all other processes: the number of spikes went down but at least one of them was still there.

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  • Bash: how to simply parallelize tasks?

    - by NoozNooz42
    I'm writing a tiny script that calls the "PNGOUT" util on a few hundred PNG files. I simply did this: find $BASEDIR -iname "*png" -exec pngout {} \; And then I looked at my CPU monitor and noticed only one of the core was used, which is quite sad. In this day and age of dual, quad, octo and hexa (?) cores desktop, how do I simply parallelize this task with Bash? (it's not the first time I've had such a need, for quite a lot of these utils are mono-threaded... I already had the case with mp3 encoders). Would simply running all the pngout in the background do? How would my find command look like then? (I'm not too sure how to mix find and the '&' character) I if have three hundreds pictures, this would mean swapping between three hundreds processes, which doesn't seem great anyway!? Or should I copy my three hundreds files or so in "nb dirs", where "nb dirs" would be the number of cores, then run concurrently "nb finds"? (which would be close enough) But how would I do this?

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  • Orthogonal projection and texture coordinates in opengl

    - by knuck
    I'm writing a 2D game in Opengl. I already set up the orthogonal projection so I can easily know where a quad will end up on screen. The problem is, I also want to be able to map pixels directly to texture coords, so I also applied an orthogonal transformation (using gluOrtho2d) to the texture. Now I can map pixels directly using integers and glTexCoord2i. The thing is, after googling/reading/asking, I found out no one really knows (apparently) the behavior of glTexCoord2i, but it works just fine the way I'm using. Some sample test code I wrote follows: glBegin(GL_QUADS); glTexCoord2i(16,0); glVertex2f(X, Y); glTexCoord2i(16,16); glVertex2f(X, Y+32); glTexCoord2i(32, 16); glVertex2f(X+32, Y+32); glTexCoord2i(32, 0); glVertex2f(X+32, Y); glEnd(); So, is there any problem with what I'm doing, or is what I'm doing correct?

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  • Performance degrades for more than 2 threads on Xeon X5355

    - by zoolii
    Hi All, I am writing an application using boost threads and using boost barriers to synchronize the threads. I have two machines to test the application. Machine 1 is a core2 duo (T8300) cpu machine (windows XP professional - 4GB RAM) where I am getting following performance figures : Number of threads :1 , TPS :21 Number of threads :2 , TPS :35 (66 % improvement) further increase in number of threads decreases the TPS but that is understandable as the machine has only two cores. Machine 2 is a 2 quad core ( Xeon X5355) cpu machine (windows 2003 server with 4GB RAM) and has 8 effective cores. Number of threads :1 , TPS :21 Number of threads :2 , TPS :27 (28 % improvement) Number of threads :4 , TPS :25 Number of threads :8 , TPS :24 As you can see, performance is degrading after 2 threads (though it has 8 cores). If the program has some bottle neck , then for 2 thread also it should have degraded. Any idea? , Explanations ? , Does the OS has some role in performance ? - It seems like the Core2duo (2.4GHz) scales better than Xeon X5355 (2.66GHz) though it has better clock speed. Thank you -Zoolii

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  • Splitting build cross the network?

    - by Dandikas
    Is there a known solution for splitting build process cross the network machines? Use case: We are an average software development company. We own around 50 development workstations (Quad Core 2.66Ghz, 4 GB ram, 200 GB raid). No need to tell that at any single moment not every machine is loaded to the max. There are 5 to 15 projects running simultaneously at any single moment. Obviously all of them are continuously build on server, than deployed to proper environment. Single project build is taking from 3 to 15 minutes. The problem: Whenever we build 5 projects in a row the last project is going to be ready after around 25 - 50 minutes. Building in parallel does not solve the problem (build is only a part of the game, than you need to deploy, run tests etc.) YES the correct solution is to add another build server, but "That involves buying new Expensive hardware, and we already spent a lot!". Yea, right(damn them)! Anyway. What about splitting build among developers workstation? Lets say whenever we need to build project "A" we check 5 workstations and start build on all that are not overloaded. The build can be canceled by a developer if he really needs all the power of his machine as long as there is at least 1 machine that is still building. After build is finished deployment can be performed to a proper environment (hosted on some server, not on workstation :) ). The bigger the company the more this makes sense to me. Anyone tried something like this? Are there any good practices? Any helpful software? (90% of the projects are .net C#)

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  • QuadTrees - how to update when internal items are moving

    - by egarcia
    I've implemented a working QuadTree. It subdivides 2-d space in order to accomodate items, identified by their bounding box (x,y,width,height) on the smallest possible quad (up to a minimum area). My code is based on this implementation (mine is in Lua instead of C#) : http://www.codeproject.com/KB/recipes/QuadTree.aspx I've been able to successfully implement insertions and deletions successfully. I've turn now my attention to the update() function, since my items' position and dimensions change over time. My first implementation works, but it is quite naïve: function QuadTree:update(item) self:remove(item) return self.root:insert(item) end Yup, I basically remove and reinsert every item every time they move. This works, but I'd like to optimize it a bit more; after all, most of the time, moving items still remain on the same quadTree node most of the iterations. Is there any standard way to deal with this kind of update? In case it helps, my code is here: http://github.com/kikito/passion/blob/master/ai/QuadTree.lua I'm not looking for someone to implement it for me; pointers to an existing working implementation (even in other languages) would suffice.

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  • Threading is slow and unpredictable?

    - by Jake
    I've created the basis of a ray tracer, here's my testing function for drawing the scene: public void Trace(int start, int jump, Sphere testSphere) { for (int x = start; x < scene.SceneWidth; x += jump) { for (int y = 0; y < scene.SceneHeight; y++) { Ray fired = Ray.FireThroughPixel(scene, x, y); if (testSphere.Intersects(fired)) sceneRenderer.SetPixel(x, y, Color.Red); else sceneRenderer.SetPixel(x, y, Color.Black); } } } SetPixel simply sets a value in a single dimensional array of colours. If I call the function normally by just directly calling it it runs at a constant 55fps. If I do: Thread t1 = new Thread(() => Trace(0, 1, testSphere)); t1.Start(); t1.Join(); It runs at a constant 50fps which is fine and understandable, but when I do: Thread t1 = new Thread(() => Trace(0, 2, testSphere)); Thread t2 = new Thread(() => Trace(1, 2, testSphere)); t1.Start(); t2.Start(); t1.Join(); t2.Join(); It runs all over the place, rapidly moving between 30-40 fps and sometimes going out of that range up to 50 or down to 20, it's not constant at all. Why is it running slower than it would if I ran the whole thing on a single thread? I'm running on a quad core i5 2500k.

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  • OpenGL Colour Interpolation

    - by Will-of-fortune
    I'm currently working on an little project in C++ and OpenGL and am trying to implement a colour selection tool similar to that in photoshop, as below. However I am having trouble with interpolation of the large square. Working on my desktop computer with a 8800 GTS the result was similar but the blending wasn't as smooth. This is the code I am using: GLfloat swatch[] = { 0,0,0, 1,1,1, mR,mG,mB, 0,0,0 }; GLint swatchVert[] = { 400,700, 400,500, 600,500, 600,700 }; glVertexPointer(2, GL_INT, 0, swatchVert); glColorPointer(3, GL_FLOAT, 0, swatch); glDrawArrays(GL_QUADS, 0, 4); Moving onto my laptop with Intel Graphics HD 3000, this result was even worse with no change in code. I thought it was OpenGL splitting the quad into two triangles, so I tried rendering using triangles and interpolating the colour in the middle of the square myself but it still doesnt quite match the result I was hoping for. Any help would be appreciated. Thanks.

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  • Adding a decal using multitexturing on an iPhone

    - by Axis
    I'm trying to overlay one image on top of another onto a simple quad. I set my bottom image as texture unit 0, and then my top image (which has a variable alpha) as texture unit 1. Unit 2 has mode GL_DECAL, which means the bottom texture should show up when the alpha is 0, and the top texture should show when the alpha is 1. But, only the top texture shows up and the bottom one doesn't appear at all. It's just white where the bottom texture should show through. glGetError() doesn't report any problems. Any help is appreciated. Thanks! glVertexPointer(3, GL_FLOAT, 0, boxVertices); glEnableClientState(GL_VERTEX_ARRAY); glClientActiveTexture(GL_TEXTURE0); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glTexCoordPointer(2, GL_FLOAT, 0, boxTextureCoords); glClientActiveTexture(GL_TEXTURE1); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glTexCoordPointer(2, GL_FLOAT, 0, boxTextureCoords); glClientActiveTexture(GL_TEXTURE0); glEnable(GL_TEXTURE_2D); glClientActiveTexture(GL_TEXTURE1); glEnable(GL_TEXTURE_2D); glClientActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, one.texture); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glClientActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, two.texture); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL); glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

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  • Thoughts on GoGrid vs EC2

    - by Jason
    I am currently hosting my SaaS application at GoGrid (Microsoft stack). Here's what I have: Database Server - physical box, 12 GB RAM, 2 X Quad Core CPU (2.13 GHz Xeon E5506) 2 Web / App servers - cloud servers, 2 GB RAM, 2 VCPUs 300 GB monthly bandwidth I am paying around $900 / month for this. My web / app servers are busting at the seams and need to be upgraded to 4 GB of RAM. I also need a firewall, and GoGrid just added this service for an additional $200. After the upgrade, I will be paying around $1,400. I started looking at Amazon EC2, specifically this config: Database server - "High Memory Double Extra Large Instance" - 34 GB RAM, 13 EC2 compute units 2 Web / App servers - "Large Instance" - 7.5 GB RAM, 4 EC2 compute units If I go with 1 year reserved instances, my upfront cost would be $4,500 and my monthly would be $700. This comes to $1,075 / month when amortized. Amazon also includes a firewall for free. Here are my questions: Do any of you have experience running a database (especially SQL Server) on an EC2 instance? How did it perform compared to a dedicated machine? One of my major concerns is with disk I/O. Amazon's description of a compute unit is fairly vague. Any ideas on how the CPU performance on the database servers would compare? I am hoping that the Amazon solution will provide significantly better performance than my current or even improved GoGrid setup. Having a virtual database server would also be nice in terms of availability. Right now I would be in serious trouble if I had any hardware issues. Thanks for any insight...

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