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  • How to get Windows Server 2008 VM to use multiple cores

    - by David Fraser
    I have a Windows Server 2008 machine running in VirtualBox. On initial installation, only one processor was made available, but now I want to run it as a multiprocessor machine. I have made all four cores available in the VirtualBox settings (as well as enabling VT-x/AMD-V and Nested Paging), but Task Manager still only shows one CPU. However, the four CPU cores are visible in Device Manager under Processors. In the event log on startup, I can see the following relevant events: EventLog.6009 Microsoft (R) Windows (R) 6.00.6002 Service Pack 2 Multiprocessor Free Kernel-Processor-Power.4 Processor 0 exposes the following: 1 idle state(s), 0 performance state(s), 0 throttle state(s) Kernel-Processor-Power.4 Processor 255 exposes the following: 0 idle state(s), 0 performance state(s), 0 throttle state(s) Kernel-Processor-Power.4 Processor 255 exposes the following: 0 idle state(s), 0 performance state(s), 0 throttle state(s) Kernel-Processor-Power.4 Processor 255 exposes the following: 0 idle state(s), 0 performance state(s), 0 throttle state(s) How can I make this system actually boot up as a multiprocessor machine?

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  • intel HD graphics with integrated tv tuner

    - by Tamir
    Hi all! I have new Dell laptop with Intel HD graphics with integrated TV tuner. How can i use this TV tuner? should I install third party software for using it or just configure something? I tried to google it but couldn't find a thing :-( so, How can I use this TV tuner? Many thanks!

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  • Computer freezes for 2+ seconds, mouse still moves

    - by xsaero00
    I have this problem on my workstation. The computer would effectively freeze for 2-5 seconds for no apparent reason, then continue as normal. While frozen the mouse would still be movable, but only on one of screens in my multi-screen setup. What can be the likely cause. System: CPU: i7-920 Memory: 12G of Patriot DDR3, 6 modules OS: SLED 11, Suse Linux Enterprise Desktop, using Gnome Main board: Asus P6T Video: two Nvidia 9500GT connected to three displays I am using memory at recommended settings of 8-8-8-1333. It has an XMP profile. Th CPU is a bit overclocked to 3.3 GHz, but my cooling more than allows for it. I ran the computer with all overclocks off and lower memory speed but the issue was still there. Any ideas? Where should I start looking?

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  • How to get Windows Server 2008 VM to use multiple cores

    - by David Fraser
    I have a Windows Server 2008 machine running in VirtualBox. On initial installation, only one processor was made available, but now I want to run it as a multiprocessor machine. I have made all four cores available in the VirtualBox settings (as well as enabling VT-x/AMD-V and Nested Paging), but Task Manager still only shows one CPU. However, the four CPU cores are visible in Device Manager under Processors. In the event log on startup, I can see the following relevant events: EventLog.6009 Microsoft (R) Windows (R) 6.00.6002 Service Pack 2 Multiprocessor Free Kernel-Processor-Power.4 Processor 0 exposes the following: 1 idle state(s), 0 performance state(s), 0 throttle state(s) Kernel-Processor-Power.4 Processor 255 exposes the following: 0 idle state(s), 0 performance state(s), 0 throttle state(s) Kernel-Processor-Power.4 Processor 255 exposes the following: 0 idle state(s), 0 performance state(s), 0 throttle state(s) Kernel-Processor-Power.4 Processor 255 exposes the following: 0 idle state(s), 0 performance state(s), 0 throttle state(s) How can I make this system actually boot up as a multiprocessor machine?

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  • Display with intel integrated graphics, bitcoin mine with Radeon 6950

    - by karategeek6
    I'm on Ubuntu Linux 11.04 64 bit. I have an intel i5 with integrated graphics and a Radeon 6950, with one monitor. I would like to run my graphics on the integrated card, and run bitcoin mining on the 6950. I have bitcoin mining working when I use the 6950 for both display and mining. Every time I try and and use the integrated graphics instead, OpenCL doesn't recognize my 6950. Using aticonfig --initial when using the integrated graphics for display breaks things. So I used the xorg.conf it created as a basis and tried to manually edit it. I really don't know what I'm doing, though. My last attempt is given below. The graphics ran off the integrated card, but the 6950 wasn't recognized. Any help would be greatly appreciated! xorg.conf: #Section "ServerLayout" # Identifier "Intel Layout" # Screen "Default Screen" # Identifier "aticonfig Layout" # Screen "aticonfig-Screen[0]-0" # Screen 0 "aticonfig-Screen[0]-0" 0 0 #EndSection Section "Module" Load "glx" EndSection # Intel Section "Device" Identifier "Intel Integrated Graphics" Driver "intel" BusID "PCI:0:2:0" EndSection Section "Monitor" Identifier "Default Monitor" Option "VendorName" "Monitor Vendor" Option "ModelName" "Monitor Name" Option "DPMS" "true" EndSection Section "Screen" Identifier "Default Screen" Device "Intel Integrated Graphics" Monitor "Default Monitor" DefaultDepth 24 EndSection # ATI Section "Device" Identifier "aticonfig-Device[0]-0" Driver "fglrx" BusID "PCI:1:0:0" EndSection Section "Monitor" Identifier "aticonfig-Monitor[0]-0" Option "VendorName" "ATI Proprietary Driver" Option "ModelName" "Generic Autodetecting Monitor" Option "DPMS" "true" EndSection Section "Screen" Identifier "aticonfig-Screen[0]-0" Device "aticonfig-Device[0]-0" Monitor "aticonfig-Monitor[0]-0" DefaultDepth 24 SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection

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  • SQL 2008 R2: Data\Log partions

    - by Reese Hirth
    I have a SQL Server setup that a previous IT person set up with a 2TB data partition and a 1TB log partition. The OS partition is 244GB and SQL is installed on a separate 1TB partition. We have an additional 8TB of storage that I would like the new IT staff to bring on line. He wants to create 4 new 2TB data partition. I see this as confusing. Can't we just backup the current data partition, blow it away, and create a new 10TB data partition I'm responsible for administering the data on the server but am not allowed to do the setup myself. This is a GIS server running ArcGIS Server with around 60 geodatabases ranging from 20BG to a couple that may grow to over a TB. So, 5-2TB data partitions or 1-10TB partition. Thanks for the advice.

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  • Nvidia 9 series or Intel HD 2000? [closed]

    - by EApubs
    I just tested an Nvidia 9300 GS card with a Intel Corei3 HD 2000 graphics system. Here is the windows experience index scores I got : Nvidia 9300 GS : Base Score 3.9 Processor : 7.1 Memory : 7.5 Graphics : 3.9 Gaming Graphics : 5.1 Hard Disk : 5.9 Intel HD 2000 : Base Score : 5.2 Processor : 7.1 Memory : 5.9 Graphics : 5.2 Gaming Graphics : 5.8 Hard Disk : 5.9 My questions are : When using Intel HD graphics, it reduces the score of my Ram! How is that possible? It checks the speed of the ram. Not the size (i think). Intel graphics take some of the ram space but how can that effect the speed? From both of them, what will be the good choice?

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  • PC wont boot with more than 1 stick of RAM.

    - by Aidan
    Hi Guys, I've got the following computer and I've just put in a new CPU QX9650 and I've run into this problem since making this hardware change. Whenever I put more than 1 of my 4 sticks of ram into my machine it wont load an OS. It'll go through the BIOS but BSOD on windows load. It also wont let me install an OS from disk or boot into Linux. I've ran memtest with all 4 sticks in and I get 10k+ errors on test5. Each stick of ram on it's own is fine and functions properly. I only have problems when all 4 sticks are in the machine at the same time. System specs.. CPU: QX9650 Mobo: Asus P5B 2104 BIOS RAM: 2xPC25400 DDR2 , 2xPC2 6400 both OCZ. Is the problem on my end or is the CPU faulty?

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  • PC wont boot with more than 1 stick of RAM.

    - by Aidan
    Hi Guys, I've got the following computer and I've just put in a new CPU QX9650 and I've run into this problem since making this hardware change. Whenever I put more than 1 of my 4 sticks of ram into my machine it wont load an OS. It'll go through the BIOS but BSOD on windows load. It also wont let me install an OS from disk or boot into Linux. I've ran memtest with all 4 sticks in and I get 10k+ errors on test5. Each stick of ram on it's own is fine and functions properly. I only have problems when all 4 sticks are in the machine at the same time. System specs.. CPU: QX9650 Mobo: Asus P5B 2104 BIOS RAM: 2xPC25400 DDR2 , 2xPC2 6400 both OCZ. Is the problem on my end or is the CPU faulty?

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  • /data/tmp on database server?

    - by Mellon
    I am on a Linux ubuntu machine with MySQL installed. My teacher gave out an assignment which mentioned "copy cars.dat to /data/tmp on the MySQL database server" without any explanations, I do not know what is the "/data/tmp on database server" means exactly? Basically after that I need to execute SQL statement like LOAD DATA INFILE '/data/tmp/cars.dat' INTO TABLE cars So, what does copy cars.dat to /data/tmp on the database server means as there is no /data/tmp directory even? Personally, I checked /etc/mysql/my.cnf file, inside which there are definitions of : ... basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp ... Does it mean to copy cars.dat to the tmpdir which is just /tmp under root directory??

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  • kill SIGABRT does not generate core file from daemon started from crontab.

    - by Guma
    I am running CentOS 5.5 and working on server application that sometimes I need to force core dump so I can see what is going on. If I start my server from shell and send kill SIGABRT, a core file is created. If I start same program from crontab and then I send the same signal to it the server is "killed" but no core file is generated. Does any one know why is that and what need to be added to my code or changed in system settings to allow core file generation? Just a side note I have ulimit set to unlimited in /etc/profile I have set kernel.core_uses_pid = 1 kernel.core_pattern=/var/cores/%h-%e-%p.core in /etc/sysctl.conf Also my server app was added to crontab under same login id as I am running it from shell. Any help greatly appreciated

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  • Datacenter Backup Strategy

    - by EasyEcho
    What are common approaches to backup solutions in remote data centers? I am already familiar with general backup principals and have a very good backup strategy for our local data center but am having great difficulty extending it to a remote data center. We currently do a full backup on Friday, differential Mon - Thu, rotate offsite Friday morning ...rinse and repeat week after week. BTW, we use disks and have been very happy with this approach. We could buy a large storage server and backup everything to it, but this solution doesn't give you offsite. We could encrypt and upload to Amazon or some other online storage but that would take a large amount of time given the data and would be rather expensive paying for the bandwidth leaving the data center and receiving at amazon. We could drive to the data center every Friday and continue to rotate disks as we do now. But that just seems old fashion. What am I missing, are there better options?

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  • Is there any way to limit the turbo boost speed / intensity on i7 lap?

    - by Anonymous
    I've just got a used i7 laptop, one of these overheating pavilions from HP with quad cores. And I really want to find a compromise between the temp and performance. If I use linpack, or some other heavy benchmark, the temp easily gets to 95+, and having a TJ of 100 Degrees, for a 2630QM model, it really gets me throttling, that no cooling pad or even an industrial fan could solve. I figured later that it is due to turbo boost, and if I set my power settings to use 99% of the CPU instead of 100%, and it seems to disable the turbo boost, so the temp gets better. But then again it loses quite a bit of performance. The regular clock is 2GHz, and in turbo boost it gets to 2.6Ghz, but I just wonder if I could limit it to around 2.3Ghz, that would be a real nice thing. Also there is another question I've hard time getting answer to. It seems to me that clocks are very quickly boosting up to max even when not needed, eg, it's ok if the CPU has 0% load, the clocks get to their 800MHz, but even if it gets to about 5% it quickly jumps to a max and even popping up turbo, which seems very strange to me. So I wonder if there is any way to adjust the sensitivity of the Speed Step feature. I believe it would be more logical to demand increased clock if it hits let's say 50% load. I do understand that most of these features are probably hardwired somewhere in the CPU itself or the MB, which has no tuning options just like on many laptops. But I would appreciate if you could recommend some thing, or some software. Thanks

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  • SQL server availability issue: large query stops other connections from connecting

    - by Carlos
    I've got a high-spec (multicore, RAID) server running MS SQL 2008, with several databases on it. I have a low throughput process that periodically needs a small amount of information from one of the DBs, and the code seems to work fine. However, sometimes when one of my colleagues does a huge query against one of the other DBs, I see full CPU usage on the machine, and connections from my app time out. Why does this happen? I would have thought the many cores and harddisks would somehow (together with cleverly written DB server) be able to keep at least some of the resources free for other apps? I'm pretty sure he doesn't use multiple connections for his query. What can I do to prevent this?

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  • How to achieve redundancy across data centers?

    - by BrandonBT
    I have a LAMP server with a lot of hardware redundancy built in. I am not worried about the server becoming unavailable. What I am worried about, however, are potential network issues in the data center the server is in. What I would like to have is another server in another data center for redundancy. Load balancing is less of a concern. With that said, I am relatively clueless on two points: How to have two servers in two geographically separate data centers that have exactly the same data, in terms of both files and MySQL databases. How to ensure that all traffic coming into one data center are automatically transferred to the other database in the case of a network or server failure at the first data center. Any guidance on how to accomplish the above two problems would be greatly appreciated.

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  • i7-980X at 70% speed

    - by Buxley
    Hi we bought a nice computer to use to solve optimization problems. Intel i7-980X@3,33 GHz with 12 GB of Team Group 1600 MHz DDR3 RAM. When we use Gurobi the computer uses all 12 cores at maximum in the beginning of the solve. However after a while (about 8 hrs) it all cores jump between 65 and 85% When I solve the same models on an i7 930 all cores are at a near 100% level even after longer solution times. We first thought that the Hard disk was the bottleneck since Gurobi writes out nodefiles after the memorylimit is used. However since the new computer have 12 GB of RAM we put the memorylimit to 7 GB so the solver only used the RAM and still with the same performance in the processor. Any ideas about the bottleneck? As I said earlier it works at 100% for the first hours or so . Thanks very much for any answers! Our plan was to overclock it but we can't even get it to work at normal speed yet!

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  • i7 x980 at 70% speed

    - by Buxley
    Hi we bought a nice computer to use to solve optimization problems. intel i7 X980@3,33 Mhz with 12 Gb of Team Group 1600 MHz ddr3 Ram. When we use Gurobi The Computer uses all 12 cores at maximum in the beginning of the solve. However after a while (about 8 hrs) it all cores jump between 65 and 85% When I solve the same models on an I7 930 all cores are at a near 100% level even after longer solution times. we first thought that the Harddisk was the bottleneck since Gurobi writes out nodefiles after the memorylimit is used. However since the new computer have 12 GB of Ram we put the memorylimit to 7 GB so the solver only used the RAM and still with the same performance in the processor. Any Ideas about the bottleneck? As I said earlier it works at 100% for the first hours or so . Thanks very much for any answers! Our plan was to overclock it but we can't even get it to work at normal speed yet!

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  • What is good RAM for my CPU?

    - by Jason94
    I'm going to upgrade my RAM, but I have no clue what to look for. There is cheap and there is expensive RAM. What should I look for? What are good attributes for intel i5? The i5 CPU and motherboeard supports 1600 MHz (PC3-12800), but there is still to much to choose from. There are CL10 (10-10-10-27) @ 1.5V CL11 @ 1.35V CL9 (9-9-9-24) @ 1.5V CL9 (9-9-9-24) @ 1.65V Higher CL is better? CL is classification? And I guess a high voltage is also good since thats what overclockers do to the ram (increase the voltage)?

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  • Recovering damaged external hard disk by installing internally

    - by nfarshchi
    I had a 1TB Western Digital (My book series) 3.5" USB3. One day, the SATA to USB3 converter board was damaged and has not worked since. I decided to open the cover and use the HDD as an internal HDD. When I attached the HDD to my PC and booted up in Windows, it asked me which type of ????? I want to use "MBR or GBR" (I dont remember the exact question) I chose MBR and Windows gave me a 1TB empty Hard drive. I tried to recover with recover my files and some other recovery programs but no success. Some one told me that you should choosed GBR instead of MBR . How can I do that now? Another guy told me that the SATA to USB3 converter board is coded to save data on HDD and you can not use them internally without losing data, and I should find another SATA to USB3 board (exact same). It is impossible to find because they are not produced any more. Please help me to find a solution to bring back my data. UPDATE I have 1TB WD "Mybook" USB 3. the board that convert sata to usb3 was damaged. so when the HDD was in the box computer did not recognize it. I opened the box and remove HDD to use it internal. after connecting to my PC windows showed me one massage that I had two choice MBR or GPT I choosed MBR one and windows gave me 1TB empty new volume. I tried many recovery software to recover my data but no success. I brought it to one expert recovery company and they told me the converter board (SATA to USB3) make some encryption on data and with out that board you cannot recover any thing. so I bought another empty WD box and put the HDD inside but even after that also there is no file. I tried to recover again in this state but no success. so I have some unanswered question. does this converted boards make any password or encryption? if yes how can I solve it? does using many recovery programs affected my data? any suggestion or solution for bring back my data? I had use recovery programs such as : recover my files , EaseUS data recovery, easy recovery, test disk, Ontrack easy recovery . Note: when I was using test disk it asked me to choose which partition table I want to use. as it was I choose NTFS, does this made any change on data?

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  • Export data to Excel from Silverlight/WPF DataGrid

    - by outcoldman
    Data export from DataGrid to Excel is very common task, and it can be solved with different ways, and chosen way depend on kind of app which you are design. If you are developing app for enterprise, and it will be installed on several computes, then you can to advance a claim (system requirements) with which your app will be work for client. Or customer will advance system requirements on which your app should work. In this case you can use COM for export (use infrastructure of Excel or OpenOffice). This approach will give you much more flexibility and give you possibility to use all features of Excel app. About this approach I’ll speak below. Other way – your app is for personal use, it can be installed on any home computer, in this case it is not good to ask user to install MS Office or OpenOffice just for using your app. In this way you can use foreign tools for export, or export to xml/html format which MS Office can read (this approach used by JIRA). But in this case will be more difficult to satisfy user tasks, like create document with landscape rotation and with defined fields for printing. At this article I'll show you how to work with Excel object from .NET 4 and Silverlight 4 with dynamic objects and give you an approach which allow you to export data from DataGrid Silverlight and WPF controls. Read more...

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  • Parallelism in .NET – Part 3, Imperative Data Parallelism: Early Termination

    - by Reed
    Although simple data parallelism allows us to easily parallelize many of our iteration statements, there are cases that it does not handle well.  In my previous discussion, I focused on data parallelism with no shared state, and where every element is being processed exactly the same. Unfortunately, there are many common cases where this does not happen.  If we are dealing with a loop that requires early termination, extra care is required when parallelizing. Often, while processing in a loop, once a certain condition is met, it is no longer necessary to continue processing.  This may be a matter of finding a specific element within the collection, or reaching some error case.  The important distinction here is that, it is often impossible to know until runtime, what set of elements needs to be processed. In my initial discussion of data parallelism, I mentioned that this technique is a candidate when you can decompose the problem based on the data involved, and you wish to apply a single operation concurrently on all of the elements of a collection.  This covers many of the potential cases, but sometimes, after processing some of the elements, we need to stop processing. As an example, lets go back to our previous Parallel.ForEach example with contacting a customer.  However, this time, we’ll change the requirements slightly.  In this case, we’ll add an extra condition – if the store is unable to email the customer, we will exit gracefully.  The thinking here, of course, is that if the store is currently unable to email, the next time this operation runs, it will handle the same situation, so we can just skip our processing entirely.  The original, serial case, with this extra condition, might look something like the following: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) break; customer.LastEmailContact = DateTime.Now; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re processing our loop, but at any point, if we fail to send our email successfully, we just abandon this process, and assume that it will get handled correctly the next time our routine is run.  If we try to parallelize this using Parallel.ForEach, as we did previously, we’ll run into an error almost immediately: the break statement we’re using is only valid when enclosed within an iteration statement, such as foreach.  When we switch to Parallel.ForEach, we’re no longer within an iteration statement – we’re a delegate running in a method. This needs to be handled slightly differently when parallelized.  Instead of using the break statement, we need to utilize a new class in the Task Parallel Library: ParallelLoopState.  The ParallelLoopState class is intended to allow concurrently running loop bodies a way to interact with each other, and provides us with a way to break out of a loop.  In order to use this, we will use a different overload of Parallel.ForEach which takes an IEnumerable<T> and an Action<T, ParallelLoopState> instead of an Action<T>.  Using this, we can parallelize the above operation by doing: Parallel.ForEach(customers, (customer, parallelLoopState) => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) parallelLoopState.Break(); else customer.LastEmailContact = DateTime.Now; } }); There are a couple of important points here.  First, we didn’t actually instantiate the ParallelLoopState instance.  It was provided directly to us via the Parallel class.  All we needed to do was change our lambda expression to reflect that we want to use the loop state, and the Parallel class creates an instance for our use.  We also needed to change our logic slightly when we call Break().  Since Break() doesn’t stop the program flow within our block, we needed to add an else case to only set the property in customer when we succeeded.  This same technique can be used to break out of a Parallel.For loop. That being said, there is a huge difference between using ParallelLoopState to cause early termination and to use break in a standard iteration statement.  When dealing with a loop serially, break will immediately terminate the processing within the closest enclosing loop statement.  Calling ParallelLoopState.Break(), however, has a very different behavior. The issue is that, now, we’re no longer processing one element at a time.  If we break in one of our threads, there are other threads that will likely still be executing.  This leads to an important observation about termination of parallel code: Early termination in parallel routines is not immediate.  Code will continue to run after you request a termination. This may seem problematic at first, but it is something you just need to keep in mind while designing your routine.  ParallelLoopState.Break() should be thought of as a request.  We are telling the runtime that no elements that were in the collection past the element we’re currently processing need to be processed, and leaving it up to the runtime to decide how to handle this as gracefully as possible.  Although this may seem problematic at first, it is a good thing.  If the runtime tried to immediately stop processing, many of our elements would be partially processed.  It would be like putting a return statement in a random location throughout our loop body – which could have horrific consequences to our code’s maintainability. In order to understand and effectively write parallel routines, we, as developers, need a subtle, but profound shift in our thinking.  We can no longer think in terms of sequential processes, but rather need to think in terms of requests to the system that may be handled differently than we’d first expect.  This is more natural to developers who have dealt with asynchronous models previously, but is an important distinction when moving to concurrent programming models. As an example, I’ll discuss the Break() method.  ParallelLoopState.Break() functions in a way that may be unexpected at first.  When you call Break() from a loop body, the runtime will continue to process all elements of the collection that were found prior to the element that was being processed when the Break() method was called.  This is done to keep the behavior of the Break() method as close to the behavior of the break statement as possible. We can see the behavior in this simple code: var collection = Enumerable.Range(0, 20); var pResult = Parallel.ForEach(collection, (element, state) => { if (element > 10) { Console.WriteLine("Breaking on {0}", element); state.Break(); } Console.WriteLine(element); }); If we run this, we get a result that may seem unexpected at first: 0 2 1 5 6 3 4 10 Breaking on 11 11 Breaking on 12 12 9 Breaking on 13 13 7 8 Breaking on 15 15 What is occurring here is that we loop until we find the first element where the element is greater than 10.  In this case, this was found, the first time, when one of our threads reached element 11.  It requested that the loop stop by calling Break() at this point.  However, the loop continued processing until all of the elements less than 11 were completed, then terminated.  This means that it will guarantee that elements 9, 7, and 8 are completed before it stops processing.  You can see our other threads that were running each tried to break as well, but since Break() was called on the element with a value of 11, it decides which elements (0-10) must be processed. If this behavior is not desirable, there is another option.  Instead of calling ParallelLoopState.Break(), you can call ParallelLoopState.Stop().  The Stop() method requests that the runtime terminate as soon as possible , without guaranteeing that any other elements are processed.  Stop() will not stop the processing within an element, so elements already being processed will continue to be processed.  It will prevent new elements, even ones found earlier in the collection, from being processed.  Also, when Stop() is called, the ParallelLoopState’s IsStopped property will return true.  This lets longer running processes poll for this value, and return after performing any necessary cleanup. The basic rule of thumb for choosing between Break() and Stop() is the following. Use ParallelLoopState.Stop() when possible, since it terminates more quickly.  This is particularly useful in situations where you are searching for an element or a condition in the collection.  Once you’ve found it, you do not need to do any other processing, so Stop() is more appropriate. Use ParallelLoopState.Break() if you need to more closely match the behavior of the C# break statement. Both methods behave differently than our C# break statement.  Unfortunately, when parallelizing a routine, more thought and care needs to be put into every aspect of your routine than you may otherwise expect.  This is due to my second observation: Parallelizing a routine will almost always change its behavior. This sounds crazy at first, but it’s a concept that’s so simple its easy to forget.  We’re purposely telling the system to process more than one thing at the same time, which means that the sequence in which things get processed is no longer deterministic.  It is easy to change the behavior of your routine in very subtle ways by introducing parallelism.  Often, the changes are not avoidable, even if they don’t have any adverse side effects.  This leads to my final observation for this post: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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  • Writing algorithm on 2D data set in plain english

    - by Alexandre P. Levasseur
    I have started an introductory Java class and the material is absolutely horrendous and I have to get excellent grades to be accepted into the master's degree, hence my very beginner question: In my assignment I have to write algorithms (no pseudo-code yet) to solve a board game (Sudoku). Essentially, the notes say that an algorithm is specification of the input(s), the output(s) and the treatments applied to the input to get the output. My question lies on the wording of algorithms because I could probably code it but I can't seem to put it on paper in a coherent way. The game has a 9x9 board and one of the algorithms to write has to find the solution by looking at 3 squares (either horizontal or vertical) and see if one of the three sub-squares match the number you are looking for. If none match then the number you are looking to place is in one of the other 2 set of 3 sub-squares (see image to get a better idea). I really can't get my head around how to formulate the solution into the terms described above or maybe it's just too simple, here's what I was thinking: Input: A 2-dimensional set of data of size 9 by 9 to be solved and a number to search for. Ouput: A 2-dimensional set of data of size 9 by 9 either solved or partially solved. Treatment: Scan each set of 3x9 and 9x3 squares. For each line or column of a 3x3 square check if the number matches a line (or column). If it does then move to the next line (or column). If not then proceed to the next 3x3 square in the same line (or column). Rinse and repeat. Does that make sense as an algorithm written in plain english ? I'm not looking for an answer to the algorithm per se but rather on the formulation of algorithms in plain english.

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