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  • Mongodb performance on Windows

    - by Chris
    I've been researching nosql options available for .NET lately and MongoDB is emerging as a clear winner in terms of availability and support, so tonight I decided to give it a go. I downloaded version 1.2.4 (Windows x64 binary) from the mongodb site and ran it with the following options: C:\mongodb\bin>mkdir data C:\mongodb\bin>mongod -dbpath ./data --cpu --quiet I then loaded up the latest mongodb-csharp driver from http://github.com/samus/mongodb-csharp and immediately ran the benchmark program. Having heard about how "amazingly fast" MongoDB is, I was rather shocked at the poor benchmark performance. Starting Tests encode (small).........................................320000 00:00:00.0156250 encode (medium)........................................80000 00:00:00.0625000 encode (large).........................................1818 00:00:02.7500000 decode (small).........................................320000 00:00:00.0156250 decode (medium)........................................160000 00:00:00.0312500 decode (large).........................................2370 00:00:02.1093750 insert (small, no index)...............................2176 00:00:02.2968750 insert (medium, no index)..............................2269 00:00:02.2031250 insert (large, no index)...............................778 00:00:06.4218750 insert (small, indexed)................................2051 00:00:02.4375000 insert (medium, indexed)...............................2133 00:00:02.3437500 insert (large, indexed)................................835 00:00:05.9843750 batch insert (small, no index).........................53333 00:00:00.0937500 batch insert (medium, no index)........................26666 00:00:00.1875000 batch insert (large, no index).........................1114 00:00:04.4843750 find_one (small, no index).............................350 00:00:14.2812500 find_one (medium, no index)............................204 00:00:24.4687500 find_one (large, no index).............................135 00:00:37.0156250 find_one (small, indexed)..............................352 00:00:14.1718750 find_one (medium, indexed).............................184 00:00:27.0937500 find_one (large, indexed)..............................128 00:00:38.9062500 find (small, no index).................................516 00:00:09.6718750 find (medium, no index)................................316 00:00:15.7812500 find (large, no index).................................216 00:00:23.0468750 find (small, indexed)..................................532 00:00:09.3906250 find (medium, indexed).................................346 00:00:14.4375000 find (large, indexed)..................................212 00:00:23.5468750 find range (small, indexed)............................440 00:00:11.3593750 find range (medium, indexed)...........................294 00:00:16.9531250 find range (large, indexed)............................199 00:00:25.0625000 Press any key to continue... For starters, I can get better non-batch insert performance from SQL Server Express. What really struck me, however, was the slow performance of the find_nnnn queries. Why is retrieving data from MongoDB so slow? What am I missing? Edit: This was all on the local machine, no network latency or anything. MongoDB's CPU usage ran at about 75% the entire time the test was running. Edit 2: Also, I ran a trace on the benchmark program and confirmed that 50% of the CPU time spent was waiting for MongoDB to return data, so it's not a performance issue with the C# driver.

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  • SQL Profiler: Read/Write units

    - by Ian Boyd
    i've picked a query out of SQL Server Profiler that says it took 1,497 reads: EventClass: SQL:BatchCompleted TextData: SELECT Transactions.... CPU: 406 Reads: 1497 Writes: 0 Duration: 406 So i've taken this query into Query Analyzer, so i may try to reduce the number of reads. But when i turn on SET STATISTICS IO ON to see the IO activity for the query, i get nowhere close to one thousand reads: Table Scan Count Logical Reads =================== ========== ============= FintracTransactions 4 20 LCDs 2 4 LCTs 2 4 FintracTransacti... 0 0 Users 1 2 MALs 0 0 Patrons 0 0 Shifts 1 2 Cages 1 1 Windows 1 3 Logins 1 3 Sessions 1 6 Transactions 1 7 Which if i do my math right, there is a total of 51 reads; not 1,497. So i assume Reads in SQL Profiler is an arbitrary metric. Does anyone know the conversion of SQL Server Profiler Reads to IO Reads? See also SQL Profiler CPU / duration unit Query Analyzer VS. Query Profiler Reads, Writes, and Duration Discrepencies

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  • WMI Windows 7 vs Server 2003 R2 Problem

    - by Shahmir Javaid
    I have the below procedures running one after the Other. It seems to work fine in Windows 7 but fails on Windows Server 2003 R2. Any Ideas Why? Am i suppose to be disposing For Cpu ManagementObjectSearcher cpuSearcher = new ManagementObjectSearcher("root\\CIMv2", "SELECT * FROM Win32_Processor"); foreach (ManagementObject cpuObj in cpuSearcher.Get()) { cpu.Add(new cpuinfo(cpuObj["Name"].ToString())); cpuObj.Dispose(); } cpuSearcher.Dispose(); For Memory ManagementObjectSearcher memSearcher = new ManagementObjectSearcher("root\\CIMv2", "SELECT Capacity FROM Win32_PhysicalMemory"); //Get total Memory foreach (ManagementObject memObj in memSearcher.Get()) { MemTotal += (Int64.Parse((memObj["Capacity"].ToString()))); memObj.Dispose(); } Any Help would be apreaciated

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  • Equivalents to Z80 DJNZ instruction on other architectures?

    - by Justin Ethier
    First a little background. The z80 CPU has an instruction called DJNZ which can be used in a similar manner as a for loop. Basically DJNZ decrements the B register and jumps to a label if not zero. For example: ld b,96 ; erase all of the line disp_version_erase_loop: call _vputblank ; erase pixels at cursor (uses b reg) djnz disp_version_erase_loop ; loop Of course you can do the same thing using regular comparison and jump instructions, but often it is handy to use the single instruction. With that out of the way, my question is, do other CPU architectures include a similar control instruction?

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  • C# Confusing Results from Performance Test

    - by aip.cd.aish
    I am currently working on an image processing application. The application captures images from a webcam and then does some processing on it. The app needs to be real time responsive (ideally < 50ms to process each request). I have been doing some timing tests on the code I have and I found something very interesting (see below). clearLog(); log("Log cleared"); camera.QueryFrame(); camera.QueryFrame(); log("Camera buffer cleared"); Sensor s = t.val; log("Sx: " + S.X + " Sy: " + S.Y); Image<Bgr, Byte> cameraImage = camera.QueryFrame(); log("Camera output acuired for processing"); Each time the log is called the time since the beginning of the processing is displayed. Here is my log output: [3 ms]Log cleared [41 ms]Camera buffer cleared [41 ms]Sx: 589 Sy: 414 [112 ms]Camera output acuired for processing The timings are computed using a StopWatch from System.Diagonostics. QUESTION 1 I find this slightly interesting, since when the same method is called twice it executes in ~40ms and when it is called once the next time it took longer (~70ms). Assigning the value can't really be taking that long right? QUESTION 2 Also the timing for each step recorded above varies from time to time. The values for some steps are sometimes as low as 0ms and sometimes as high as 100ms. Though most of the numbers seem to be relatively consistent. I guess this may be because the CPU was used by some other process in the mean time? (If this is for some other reason, please let me know) Is there some way to ensure that when this function runs, it gets the highest priority? So that the speed test results will be consistently low (in terms of time). EDIT I change the code to remove the two blank query frames from above, so the code is now: clearLog(); log("Log cleared"); Sensor s = t.val; log("Sx: " + S.X + " Sy: " + S.Y); Image<Bgr, Byte> cameraImage = camera.QueryFrame(); log("Camera output acuired for processing"); The timing results are now: [2 ms]Log cleared [3 ms]Sx: 589 Sy: 414 [5 ms]Camera output acuired for processing The next steps now take longer (sometimes, the next step jumps to after 20-30ms, while the next step was previously almost instantaneous). I am guessing this is due to the CPU scheduling. Is there someway I can ensure the CPU does not get scheduled to do something else while it is running through this code?

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  • Why won't the VisualVM Profiler profile my application?

    - by Luke
    I've created a simple 1 file java application that iterates through a loop, calls some functions, allocates some memory, adds some numbers, etc. I run that application via eclipse's Run As->Java Application. The running application shows up in Java VisualVM under Local. I double click on that application and go to the Profiler tab. The default settings are: Start profiling from classes: my.main.package.** Do not profile classes: java.*, javax.*, sun.*, sunw.*, com.sun.* I click on CPU. The CPU and Memory buttons gray out. Nothing happens. The Status says profiling inactive. When my application terminates the Status says application terminated. What am I doing wrong here? Are there some settings I need to tweak? Do I need to set a VM flag when I launch my application?

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  • 32 bit dll importing in 64 bit .Net application

    - by scatterbraiin
    hello i'm having a problem, i try to solve it since yesterday but no luck. i have 32 bit delphi dll which i want to import in .NET Win Application. this application has to be built on ANY CPU mode. of course, there's BadImageFormatException coming, which means that in x64 application can't be loaded x86 dll.. i googled around and find solution, it said i have to do wrapper, but it wasn't clear for me. can anybody tell how to solve this problem, is there any possible way i can import 32bit Delphi dll in program builted Any CPU or x64 mode(maybe another solution).

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  • Performance of DrawingVisual vs Canvas.OnRender for lots of constantly changing shapes

    - by romkyns
    I'm working on a game-like app which has up to a thousand shapes (ellipses and lines) that constantly change at 60fps. Having read an excellent article on rendering many moving shapes, I implemented this using a custom Canvas descendant that overrides OnRender to do the drawing via a DrawingContext. The performance is quite reasonable, although the CPU usage stays high. However, the article suggests that the most efficient approach for constantly moving shapes is to use lots of DrawingVisual instances instead of OnRender. Unfortunately though it doesn't explain why that should be faster for this scenario. Changing the implementation in this way is not a small effort, so I'd like to understand the reasons and whether they are applicable to me before deciding to make the switch. Why could the DrawingVisual approach result in lower CPU usage than the OnRender approach in this scenario?

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  • How to set WCF threads to schedual differently

    - by Gilad
    Hi, I'm running a winservice that has 2 main objectives. Execute/Handle exposed webmethods. Run Inner processes that consume allot of CPU. The problem is that when I execute many inner processes |(as tasks) that are queued to the threadpool or taskpool, the execution of the webmethods takes much more time as WCF also queues its executions to the same threadpool. This even happens when setting the inner processes task priority to lowest and setting the webmethods thread priority to heights. I hoped that Framework 4.0 would improve this, and they have, but still it takes quite allot of time for the system to handle the WCF queued tasks if the CPU is handling other inner tasks. Is it possible to change the Threadpool that WCF uses to a different one? Is it possible to manually change the task queue (global task queue, local task queue). Is it possible to manually handle 2 task queues that behave differently ? Any help in the subject would be appropriated. Gilad.

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  • How to maximize http.sys file upload performance

    - by anelson
    I'm building a tool that transfers very large streaming data sets (possibly on the order of terabytes in a single stream; routinely in the tens of gigabytes) from one server to another. The client portion of the tool will read blocks from the source disk, and send them over the network. The server side will read these blocks off the network and write them to a file on the server disk. Right now I'm trying to decide which transport to use. Options are raw TCP, and HTTP. I really, REALLY want to be able to use HTTP. The HttpListener (or WCF if I want to go that route) make it easy to plug in to the HTTP Server API (http.sys), and I can get things like authentication and SSL for free. The problem right now is performance. I wrote a simple test harness that sends 128K blocks of NULL bytes using the BeginWrite/EndWrite async I/O idiom, with async BeginRead/EndRead on the server side. I've modified this test harness so I can do this with either HTTP PUT operations via HttpWebRequest/HttpListener, or plain old socket writes using TcpClient/TcpListener. To rule out issues with network cards or network pathways, both the client and server are on one machine and communicate over localhost. On my 12-core Windows 2008 R2 test server, the TCP version of this test harness can push bytes at 450MB/s, with minimal CPU usage. On the same box, the HTTP version of the test harness runs between 130MB/s and 200MB/s depending upon how I tweak it. In both cases CPU usage is low, and the vast majority of what CPU usage there is is kernel time, so I'm pretty sure my usage of C# and the .NET runtime is not the bottleneck. The box has two 6-core Xeon X5650 processors, 24GB of single-ranked DDR3 RAM, and is used exclusively by me for my own performance testing. I already know about HTTP client tweaks like ServicePointManager.MaxServicePointIdleTime, ServicePointManager.DefaultConnectionLimit, ServicePointManager.Expect100Continue, and HttpWebRequest.AllowWriteStreamBuffering. Does anyone have any ideas for how I can get HTTP.sys performance beyond 200MB/s? Has anyone seen it perform this well on any environment?

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  • learning the Lower levels of computing

    - by Ben
    I am a software developer with four years experience in .Net development, I always like to keep up to date with the latest technologies (.net related normally) being released and love learning them. I didn't however go to university and learnt all I know through helpful colleagues, .Net courses, the internet and good old books. I feel that I am a good developer, but without learning the lower levels of a computer as you would in the first year of a computer related Uni course, I get lost when talking to people about a lot of more technical lower level computing. Is there a book(s) that anyone could recommend, that would cover the lower levels of what is going on when I click "Run" in Visual Studio? I feel out of my depth when my boss says to me "Thats running in the CPU cache" or "you're limited by disk reads there", and would like to feel more confident when talking about how the hardware talks to each other (CPU to RAM etc). Apologise if thats a vague question, or has been asked before (i did check and couldn't find anything on here that answers my question).

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  • In a multithreaded app, would a multi-core or multiprocessor arrangement be better?

    - by Michael
    I've read a lot on this topic already both here (e.g., stackoverflow.com/questions/1713554/threads-processes-vs-multithreading-multi-core-multiprocessor-how-they-are or http://stackoverflow.com/questions/680684/multi-cpu-multi-core-and-hyper-thread) and elsewhere (e.g., ixbtlabs.com/articles2/cpu/rmmt-l2-cache.html or software.intel.com/en-us/articles/multi-core-introduction/), but I still am not sure about a couple things that seem very straightforward. So I thought I'd just ask. (1) Is a multi-core processor in which each core has dedicated cache effectively the same as a multiprocessor system (balanced of course for processor speed, cache size, and so on)? (2) Let's say I have some images to analyze (i.e., computer vision), and I have these images loaded into RAM. My app spawns a thread for each image that needs to be analyzed. Will this app on a shared cache multi-core processor run slower than on a dedicated cache multi-core processor, and would the latter run at the same speed as on an equivalent single-core multiprocessor machine? Thank you for the help!

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  • How to utilize my computation resources.

    - by carter-boater
    Hi all, I wrote a program to solve a complicated problem. This program is just a c# console application and doesn't do console.write until the computation part is finished, so output won't affect the performance. The program is like this: static void Main(string[] args) { Thread WorkerThread = new Thread(new ThreadStart(Run), StackSize); WorkerThread.Priority = ThreadPriority.Highest; WorkerThread.Start(); Console.WriteLine("Worker thread is runing..."); WorkerThread.Join(); } Now it takes 3 minute to run, when I open my task manager, I see it only take 12% of the cpu time. I actually have a i7 intel cpu with 6G three channel DDR3 memory. I am wondering how I can improve the utilization of my hardware. Thanks a lot

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  • How to ignore/prevent javadoc folder from validation during Eclipse Build?

    - by h2g2java
    In my war is a huge javadoc folder. There is no point in validating it since javadocs are produced by Sun(Oracle) javadoc utility. I have forgotten how I did it the last time. I need to tell Eclipse build not to validate that particular folder. Reasons why I need it: 1. the html produced by Sun javadoc generation utility does not meet the requirement that Eclipse uses - there is a bug report in Eclipse but Eclipse responds that Sun javadoc generator non-compliance is not their fault and that Eclipse intends to stick to their strict compliance. Which results in lots of html errors listed in the problems tab. 2. the javadoc folder is a remote link and high activity on that link is using up my cpu resource, and because it is a link to a remote location, that cpu high activity is sustained for long time until it finishes scanning the whole 35MB javadocs. Thanks - need help.

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  • What is the bit size of long on 64-bit Windows?

    - by acidzombie24
    Not to long ago someone told me that long are not 64 bits on 64 bit machines and i should always use int. This did not make sense to me. I seen docs (such as the one on apples official site) say that long are indeed 64 bits when compiling for a 64bit CPU. I looked up what it was on windows and found Windows: long and int remain 32-bit in length, and special new data types are defined for 64-bit integers. from http://www.intel.com/cd/ids/developer/asmo-na/eng/197664.htm?page=2 What should i use? should i define something like uw, sw ((un)signed width) as a long if not on windows. Otherwise do a check on the target CPU bitsize?

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  • Identify cause of hundreds of AJP threads in Tomcat

    - by Rich
    We have two Tomcat 6.0.20 servers fronted by Apache, with communication between the two using AJP. Tomcat in turn consumes web services on a JBoss cluster. This morning, one of the Tomcat machines was using 100% of CPU on 6 of the 8 cores on our machine. We took a heap dump using JConsole, and then tried to connect JVisualVM to get a profile to see what was taking all the CPU, but this caused Tomcat to crash. At least we had the heap dump! I have loaded the heap dump into Eclipse MAT, where I have found that we have 565 instances of java.lang.Thread. Some of these, obviously, are entirely legitimate, but the vast majority are named "ajp-6009-XXX" where XXX is a number. I know my way around Eclipse MAT pretty well, but haven't been able to find an explanation for it. If anyone has some pointers as to why Tomcat may be doing this, or some hints on finding out why using Eclipse MAT, that'd be appreciated!

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  • OpenMP + SSE gives no speedup

    - by Sayan Ghosh
    Hi, My Professor found out this interesting experiment of 3D Linearly separable Kernel Convolution using SSE and OpenMP, and gave the task to me to benchmark the statistics on our system. The author claims a crazy 18 fold speedup from the serial approach! Might not be always, but we were expecting at least a 2-4 times speedup running this on a Dual Core Intel. http://software.intel.com/en-us/articles/16bit-3d-convolution-sse4openmp-implementation-on-penryn-cpu/#comment-41994 Alas, we could find exactly no speedup. The serial code performs always better, with or without OpenMP. I am using Linux, and observed a certain trend...when no other processes are running on the system, after a while the loadavg starts increasing, and the the %CPU utilization falls down. Another probable false positive which I ran into accidentally...I started the program, then immediately paused it. Then I ran it on background with bg, and saw a speedup of more than 2. This happens all the time! Any advice would be great. Thanks, Sayan

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  • Referencing a x86 assembly in a 64bit one

    - by Jörg Battermann
    In one project we have a dependency on a legacy system and its .Net assembly which is delivered as a 'x86' and they do not provide a 'Any CPU' and/or 64bit one. Now the project itself juggles with lots of data and we hit the limitations we have with a forced x86 on the whole project due to that one assembly (if we used 64bit/any cpu it would raise a BadImageFormatException once that x86 is loaded on a 64bit machine). Now is there a (workaround)way to use a x86 assembly in a 64bit .net host app? That tiny dependency on that x86 assembly makes and keeps 99% of the project heavily limited.

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  • What's a reliable and practical way to protect software with a user license ?

    - by Frank
    I know software companies use licenses to protect their softwares, but I also know there are keygen programs to bypass them. I'm a Java developer, if I put my program online for sale, what's a reliable and practical way to protect it ? How about something like this, would it work ? <1> I use ProGuard to protect the source code. <2> Sign the executable Jar file. <3> Since my Java program only need to work on PC [I need to use JDIC in it], I wrap the final executable Jar into an .exe file which makes it harder to decompile. <4> When a user first downloads and runs my app, it checks for a Pass file on his PC. <5> If the Pass file doesn't exist, run the app in demo mode, exits in 5 minutes. <6> When demo exits a panel opens with a "Buy Now" button. This demo mode repeats forever unless step <7> happens. <7> If user clicks the "Buy Now" button, he fills out a detailed form [name, phone, email ...], presses a "Verify Info" button to save the form to a Pass file, leaving license Key # field empty in this newly generated Pass file. <8> Pressing "Verify Info" button will take him to a html form pre-filled with his info to verify what he is buying, also hidden in the form's input filed is a license Key number. He can now press a "Pay Now" button to goto Paypal to finish the process. <9> The hidden license Key # will be passed to Paypal as product Id info and emailed to me. <10> After I got the payment and Paypal email, I'll add the license Key # to a valid license Key list, and put it on my site, only I know the url. The list is updated hourly. <11> Few hours later when the user runs the app again, it can find the Pass file on his PC, but the license Key # value is empty, so it goes to the valid list url to see if its license Key # is on the list, if so, write the license Key # into the Pass file, and the next time it starts again, it will find the valid license Key # and start in purchased mode without exiting in 5 minutes. <12> If it can't find its license Key # on the list from my url, run in demo mode. <13> In order to prevent a user from copying and using another paid user's valid Pass file, the license Key # is unique to each PC [I'm trying to find how], so a valid Pass file only works on one PC. Only after a user has paid will Paypal email me the valid license Key # with his payment. <14> The Id checking goes like this : Use the CPU ID : "CPU_01-02-ABC" for example, encrypt it to the result ID : "XeR5TY67rgf", and compare it to the list on my url, if "XeR5TY67rgf" is not on my valid user list, run in demo mode. If it exists write "XeR5TY67rgf" into the Pass File license field. In order to get a unique license Key, can I use his PC's CPU Id ? Or something unique and useful [ relatively less likely to change ]. If so let's say this CPU ID is "CPU_01-02-ABC", I can encrypt it to something like "XeR5TY67rgf", and pass it to Paypal as product Id in the hidden html form field, then I'll get it from Paypal's email notification, and add it to the valid license Key # list on the url. So, even if a hacker knows it uses CPU Id, he can't write it into the Pass file field, because only encrypted Ids are valid Ids. And only my program knows how to generate the encrypted Ids. And even if another hacker knows the encrypted Id is hidden in the html form input field, as long as it's not on my url list, it's still invalid. Can anyone find any flaw in the above system ? Is it practical ? And most importantly how do I get hold of this unique ID that can represent a user's PC ? Frank

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  • Why Eventmachine Defer slower than Ruby Thread?

    - by allenwei
    I have two scripts which using mechanize to fetch google index page. I assuming Eventmachine will faster than ruby thread, but not. Eventmachine code cost "0.24s user 0.08s system 2% cpu 12.682 total" Ruby Thread code cost "0.22s user 0.08s system 5% cpu 5.167 total " Am I use eventmachine in wrong way? Who can explain it to me, thanks! 1 Eventmachine require 'rubygems' require 'mechanize' require 'eventmachine' trap("INT") {EM.stop} EM.run do num = 0 operation = proc { agent = Mechanize.new sleep 1 agent.get("http://google.com").body.to_s.size } callback = proc { |result| sleep 1 puts result num+=1 EM.stop if num == 9 } 10.times do EventMachine.defer operation, callback end end 2 Ruby Thread require 'rubygems' require 'mechanize' threads = [] 10.times do threads << Thread.new do agent = Mechanize.new sleep 1 puts agent.get("http://google.com").body.to_s.size sleep 1 end end threads.each do |aThread| aThread.join end

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  • SQL 2008 Encryption Scan

    - by Mike K.
    We recently upgraded a database server from SQL 2005 to SQL 2008 64 bit. CPU utilization is oftentimes running at 100% on all four processors now (this never happended on the SQL 2005 server). When I run sp_lock I see a number of processes waiting on a resource called [ENCRYPTION_SCAN]. I am not using any SQL 2008 encryption features. Does anyone know why I would have tasks waiting on this resource? It appears that whenever I have four processes waiting on this resource, CPU hits 100% on all four processors.

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  • Computationally intensive scala process using actors hangs uncooperatively

    - by Chick Markley
    I have a computationally intensive scala application that hangs. By hangs I means it is sitting in the process stack using 1% CPU but does not respond to kill -QUIT nor can it be attached via jdb attach. Runs 2-12 hours at 800-900% CPU before it gets stuck The application is using ~10 scala.actors. Until now I have had great success with kill -QUIT but I am bit stumped as to how to proceed. The actors write a fair amount to stdout using println which is redirected to a text file but has not been helpful so far diagnostically. I am just hoping there is some obvious technique when kill -QUIT fails that I am ignorant of. Or just confirmation that having multiple actors println asynchronously is a real bad idea (though I've been doing it for a long time only recently with these results) Details scala 2.8.1 & 2.8.0 mac osx 10.6.5 java version "1.6.0_22" Thanks

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