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  • Which opcodes are faster at the CPU level?

    - by Geotarget
    In every programming language there are sets of opcodes that are recommended over others. I've tried to list them here, in order of speed. Bitwise Integer Addition / Subtraction Integer Multiplication / Division Comparison Control flow Float Addition / Subtraction Float Multiplication / Division Where you need high-performance code, C++ can be hand optimized in assembly, to use SIMD instructions or more efficient control flow, data types, etc. So I'm trying to understand if the data type (int32 / float32 / float64) or the operation used (*, +, &) affects performance at the CPU level. Is a single multiply slower on the CPU than an addition? In MCU theory you learn that speed of opcodes is determined by the number of CPU cycles it takes to execute. So does it mean that multiply takes 4 cycles and add takes 2? Exactly what are the speed characteristics of the basic math and control flow opcodes? If two opcodes take the same number of cycles to execute, then both can be used interchangeably without any performance gain / loss? Any other technical details you can share regarding x86 CPU performance is appreciated

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  • What CPU hardware performance counter tool do you guys use?

    - by Hao Shen
    I just want to know the popular tool that I can use. Originally, I used Perfmon2. However, recently, I installed the lastest Ubuntu 12 on my Ivy Bridge i7 machine. Then there is some compilation error for the Pfmon. :< From here http://comments.gmane.org/gmane.comp.linux.perfmon2.devel/3255 , it seems that the Perfmon2 will not work after the kernel 2.6.30. So it suggests to use perf tool. I just want to confirm is there any popular application level performance counter monitor tool which can be used for the later kernel version?

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  • Is there any performance comparison between Perl web frameworks?

    - by DVK
    I have seen mentions (which sounded like unsubstantiated opinions, and dated ones at that) that Embperl is the fastest Perl web framework. I was wondering if there's a consensus on the relative speed of the major stable Perl web frameworks, or ideally, some sort of fact-based performance comparisons between implementations of the same sample webapps, or individual functionalities (e.g. session handling or form data processing), etc...?

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  • SQL Server "Long running transaction" performance counter: why no workee?

    - by Sleepless
    Please explain to me the following observation: I have the following piece of T-SQL code that I run from SSMS: BEGIN TRAN SELECT COUNT (*) FROM m WHERE m.[x] = 123456 or m.[y] IN (SELECT f.x FROM f) SELECT COUNT (*) FROM m WHERE m.[x] = 123456 or m.[y] IN (SELECT f.x FROM f) COMMIT TRAN The query takes about twenty seconds to run. I have no other user queries running on the server. Under these circumstances, I would expect the performance counter "MSSQL$SQLInstanceName:Transactions\Longest Transaction Running Time" to rise constantly up to a value of 20 and then drop rapidly. Instead, it rises to around 12 within two seconds and then oscillates between 12 and 14 for the duration of the query after which it drops again. According to the MS docs, the counter measures "The length of time (in seconds) since the start of the transaction that has been active longer than any other current transaction." But apparently, it doesn't. What gives?

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  • What could cause Vista machines to degrade in performance?

    - by gencha
    We have installed several machines running Windows Vista at a client site. These machines run the same set of applications each day and are not operated with by any user. They mainly run a 3D application for digital signage purposes. After a few months I noticed that several machines suffer from really bad stuttering. The performance is unacceptable. At first I figured it was faulty hardware. But after putting a fresh image on them, they run perfectly fine again. These are Core i7 machines with GTX 280 graphics adapters. They should be able to handle the workload without any trouble (and they do, at least for a while). I really have no idea how to track down the source of this issue. Especially since not all of the machines display the same issue.

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  • How anti-virus on the host machne affects performance of virtual machines?

    - by Ladislav Mrnka
    I'm diagnosing some issue with Oracle virtual box where virtual machine sometimes perform terribly slow (much slower then notebook with worse configuration): Notebook i7 (2 cores with HT = 4 logical CPUs), 4GB RAM, 5400 rpm disk, Win 7 64bit Virtual machine (Oracle Virtual Box) Host: i7 (4 cores with HT = 8 logical CPUs, 12 GB RAM, system runs from SSD, virtual machine from 7200 rpm disk, Win 7 64bit) Virtual machine: 4 cores assigned, 8 GB RAM assigned, Win 2008 R2 Enterprise (64 bit) Virtual machine uses bridge to separate network interface (machine has two) VPN for network communication No other virtual machine runs on the host Host has installed ESET Smart Security All SW is updated with last version. My question is if anti-virus on the host machine can somehow affect performance of the virtual machine and if so how can I turn it off without turning the anti-virus itself?

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  • Testing performance from around the world - how do I get a linux shell easily in multiple countries?

    - by Matthew O'Riordan
    We are building a socket based service where latency is paramount, and as such we have servers distributed into 7 data centres around the world. However, whilst we know we're bringing the servers closer to the clients, it's very difficult to know how effective this is, and importantly, what difference this makes compared to our competitors. As such, we want to run simple scripts that test latency and throughput for both our service and our competitors, which is easy enough using Amazon, however Amazon only have 7 data centres. We would like to know for example how we perform in locations all over the world such as South Africa, Australia, China, Peru etc. Does anyone know of any service where we could piggy back off their global infrastructure and run some scripts to test this performance? The obvious contenders are people like Monitis, but I don't think they would allow us to run custom scripts, only standard protocol monitors. Thanks for your help. Matt

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  • Does NTFS performance degrade significantly in volumes larger than five or six TB?

    - by Josh Yeager
    One of my customers is planning to set up a new document store, which will probably grow by 1-2TB per year. One of my co-workers says that Windows performance is extremely bad if it has a single NTFS volume that is bigger than five or six TB. He thinks that we need to set up their system with multiple volumes so that no single volume will exceed that limit. Is this a real problem? Does Windows or NTFS slow down when the volume size reaches several terabytes? Or is it possible to create a single volume of 10 or more TB?

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  • Is there a MySQL performance benchmark to measure the impact of utf8_unicode_ci versus utf8_general_ci?

    - by MiniQuark
    I read here and there that using the utf8_unicode_ci collation ensures a better treatment of unicode text (for example, it knowns how to expand characters such as 'œ' into 'oe' for searching and ordering) compared to the default utf8_general_ci which basically just strips diacritics. Unfortunately, both sources indicate that utf8_unicode_ci is slightly slower than utf8_general_ci. So my question is: what does "slightly slower" mean? Has anyone run benchmarks? Are we talking about a -0.01% performance impact or rather something like -25%? Thanks for your help.

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  • How can I get a windows server to collate and email 4 daily reports/graphs for server performance

    - by Glyn Darkin
    I run a windows 2008 webserver and would like to setup the most basic performance monitoring in the world. What i would like is: a plot of ASP.Net request time for each w3wp process for a 24hour period a plot of CPU% utilisation for each w3wp process for a 24hour period a plot of Memory utilisation for each w3wp process for a 24hour period a plot of network utilisation for each w3wp process for a 24hour period a plot of disk utilisation for each w3wp process for a 24hour period I would these plots to be emailed to me each morning. Anybody know what is the simplest way to set this up? Thanks for your help in advance. Glyn

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  • Performance problem with an Intel Wireless 5100

    - by Piet
    I just installed 12.04 on a HP Elitebook 2530p. The performance with wireless connection to an Eminem 4551 is very bad. Wired connection just works great. If I connect to my router (Eminent 4551) wired I have a good performance accessing internet pages with Firefox. When I try to access the same internet pages wireless I get a real bad performance. piet@piet-HP-EliteBook-2530p:~$ lspci 00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 07) 00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:03.0 Communication controller: Intel Corporation Mobile 4 Series Chipset MEI Controller (rev 07) 00:03.2 IDE interface: Intel Corporation Mobile 4 Series Chipset PT IDER Controller (rev 07) 00:03.3 Serial controller: Intel Corporation Mobile 4 Series Chipset AMT SOL Redirection (rev 07) 00:19.0 Ethernet controller: Intel Corporation 82567LM Gigabit Network Connection (rev 03) 00:1a.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03) 00:1a.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03) 00:1a.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03) 00:1a.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03) 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03) 00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 03) 00:1c.2 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 3 (rev 03) 00:1d.0 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) 00:1d.1 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) 00:1d.2 USB controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) 00:1d.7 USB controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93) 00:1f.0 ISA bridge: Intel Corporation ICH9M-E LPC Interface Controller (rev 03) 00:1f.2 SATA controller: Intel Corporation 82801IBM/IEM (ICH9M/ICH9M-E) 4 port SATA Controller [AHCI mode] (rev 03) 02:00.0 Network controller: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection 44:06.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller (rev 05) 44:06.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 22) piet@piet-HP-EliteBook-2530p:~$

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  • SQL SERVER – SQL Server Performance: Indexing Basics – SQL in Sixty Seconds #006 – Video

    - by pinaldave
    A DBA’s role is critical, because a production environment has to run 24×7, hence maintenance, trouble shooting, and quick resolutions are the need of the hour.  The first baby step into any performance tuning exercise in SQL Server involves creating, analyzing, and maintaining indexes. Though we have learnt indexing concepts from our college days, indexing implementation inside SQL Server can vary.  Understanding this behavior and designing our applications appropriately will make sure the application is performed to its highest potential. Vinod Kumar and myself we often thought about this and realized that practical understanding of the indexes is very important. One can not master every single aspects of the index. However there are some minimum expertise one should gain if performance is one of the concern. More on Indexes: SQL Index SQL Performance I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. Here is the interview of Vinod Kumar by myself. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Video

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  • Unexpected SQL Server 2008 Performance Tip: Avoid local variables in WHERE clause

    - by Jim Duffy
    Sometimes an application needs to have every last drop of performance it can get, others not so much. We’re in the process of converting some legacy Visual FoxPro data into SQL Server 2008 for an application and ran into a situation that required some performance tweaking. I figured the Making Microsoft SQL Server 2008 Fly session that Yavor Angelov (SQL Server Program Manager – Query Processing) presented at PDC 2009 last November would be a good place to start. I was right. One tip among the list of incredibly useful tips Yavor presented was “local variables are bad news for the Query Optimizer and they cause the Query Optimizer to guess”. What that means is you should be avoiding code like this in your stored procs even though it seems such an intuitively good idea. DECLARE @StartDate datetime SET @StartDate = '20091125' SELECT * FROM Orders WHERE OrderDate = @StartDate Instead you should be referencing the value directly in the WHERE clause so the Query Optimizer can create a better execution plan. SELECT * FROM Orders WHERE OrderDate = '20091125' My first thought about this one was we reference variables in the form of passed in parameters in WHERE clauses in many of our stored procs. Not to worry though because parameters ARE available to the Query Optimizer as it compiles the execution plan. I highly recommend checking out Yavor’s session for additional tips to help you squeeze every last drop of performance out of your queries. Have a day. :-|

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  • Performance of concurrent software on multicore processors

    - by Giorgio
    Recently I have often read that, since the trend is to build processors with multiple cores, it will be increasingly important to have programming languages that support concurrent programming in order to better exploit the parallelism offered by these processors. In this respect, certain programming paradigms or models are considered well-suited for writing robust concurrent software: Functional programming languages, e.g. Haskell, Scala, etc. The actor model: Erlang, but also available for Scala / Java (Akka), C++ (Theron, Casablanca, ...), and other programming languages. My questions: What is the state of the art regarding the development of concurrent applications (e.g. using multi-threading) using the above languages / models? Is this area still being explored or are there well-established practices already? Will it be more complex to program applications with a higher level of concurrency, or is it just a matter of learning new paradigms and practices? How does the performance of highly concurrent software compare to the performance of more traditional software when executed on multiple core processors? For example, has anyone implemented a desktop application using C++ / Theron, or Java / Akka? Was there a boost in performance on a multiple core processor due to higher parallelism?

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  • Configuration Tips for better Performance with ADF Mobile Apps

    - by SRINI INDLA
    Some tips to keep in mind to make sure ADF Mobile application's performance is optimal: 1. Select release mode in deployment profile. This is perhaps the most important thing to remember to ensure best performance for ADF Mobile Apps. Selecting this option causes the deployer to package optimized JVM and minified JS libs with the mobile app there by significantly improving the over all performance of the application. 2. For iOS you do not need to do anything else other than selecting  release mode in deploy profile. However, on Android you have to create a keystore and configure it in JDev --> Tools --> Preferences --> ADF Mobile --> Platforms : Android as shown in the snapshot below 3. Steps for generating the Keystore for Android using keytool :  4. Logging level setting in logging.properties: Make sure the log level is set to SEVERE for both framework logger as well as the application logger as follows oracle.adfmf.framework.level=SEVERE oracle.adfmf.application.level=SEVERE 5. When using SOAP WebServices with WebService Data Control make sure you select the option to copy the WSDL. This will cause the JDev to download the WSDL and all the XSDs referenced by the WSDL from the server at design time and package them with the application during deployment. This way the application does not incur the cost of downloading these resources at run time from the device.

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  • Bad Performance With Games Under Wine in Ubuntu 12.04

    - by Pandem
    I'm somewhat new to Linux. I've dabbled with it before but never more than just experimentation in a VM or dual boot where I almost always reverted back to Windows soon after (more due to a lack of commitment than a dislike for the OS). Anyway my problem is that in the two games (Guild Wars and Team Fortress 2) I've tried so far I get fairly bad performance. Despite both games having a "Platinum" rating I've still been forced to run both in DirectX 8, otherwise they either crash, have texture defects or the UI is missing. By "bad performance" I mean sub-30 FPS where there are some players and regular large framerate drops with video settings on low. Currently in my mind I believe the performance issues are just a problem with the drivers because my graphics card is a AMD 7850 which is virtually brand new and probably not properly supported yet but I'm unsure and would appreciate advice or tips to improve things. I have Ubuntu 12.04 installed and I am usually logged in a Gnome Classic session. I have installed AMD's proprietary drivers (Catalyst version 12.4) and have Wine 1.4 installed. I have used Winetricks to install DX9/DX10 dlls and other things.

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  • Haskell web frameworks survey

    - by Phuc Nguyen
    There are several web frameworks for Haskell like Happstack, Snap, and Yesod, and probably a few more. In what aspects do they differ from each other? For example: features (e.g. server only, or also client scripting, easy support for different kinds of database) maturity (e.g. stability, documentation quality) scalability (e.g. performance, handy abstraction) main targets Also, what are examples of real-world sites / web apps using these frameworks? Many thanks.

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  • Oracle ZFSSA Hybrid Storage Pool Demo

    - by Darius Zanganeh
    The ZFS Hybrid Storage Pool (HSP) has been around since the ZFSSA first launched.  It is one of the main contributors to the high performance we see on the Oracle ZFSSA both in benchmarks as well as many production environments.  Below is a short video I made to show at a high level just how impactful this HSP pool is on storage performance.  We squeeze a ton of performance out of our drives with our unique use of cache, write optimized ssd and read optimized ssd.  Many have written and blogged about this technology, here it is in action. Demo of the Oracle ZFSSA Hybrid Storage Pool and how it speeds up workloads.

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  • "Optimal" game loop for 2D side-scroller

    - by MrDatabase
    Is it possible to describe an "optimal" (in terms of performance) layout for a 2D side-scroller's game loop? In this context the "game loop" takes user input, updates the states of game objects and draws the game objects. For example having a GameObject base class with a deep inheritance hierarchy could be good for maintenance... you can do something like the following: foreach(GameObject g in gameObjects) g.update(); However I think this approach can create performance issues. On the other hand all game objects' data and functions could be global. Which would be a maintenance headache but might be closer to an optimally performing game loop. Any thoughts? I'm interested in practical applications of near optimal game loop structure... even if I get a maintenance headache in exchange for great performance.

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  • Java Alphabetize Algorithm Insertion sort vs Bubble Sort

    - by Chris Okyen
    I am supposed to "Develop a program that alphabetizes three strings. The program should allow the user to enter the three strings, and then display the strings in alphabetical order." It's instructed that I need to use the String library compareTo()/charAt()/toLowerCase() to make all the characters lowercase so the Lexicon comparison is also a alphabetical comparison. Input Pseudo Code: String input[3]; Scanner keyboard = new Scanner(System.in); System.out.println("Enter three strings: "); for(byte i = 0; i < 3; i++) input[i] = keyboard.next() The sorting would be Insertion Sort: 321 2 3 1 2 31 231 1 23 1 2 3 1 23 1 23 123 Bubble Sort 321 231 213 123 Which would be more efficient in this case? The bubble sort seems to be more efficient though they seem to have equal stats for worst best and avg case, but I read the Insertion Sort is quicker for small amounts of data like my case.

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  • For what types of applications is Python a bad choice?

    - by Casey Patton
    I just started learning Python, and I'd like to get some more context on the language. I realize that Python is a slow language relative to C or C++, etc. Thus, Python is probably not the best choice for applications that need to run quickly. Outside of this, it seems like Python is a great general purpose language that is easy to read and write. The available libraries give it a huge amount of functionality. Outside of performance critical applications, where is it a bad choice to use Python (and why)?

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  • What criteria would I use SQL Stream Insight vs TPL Dataflow [closed]

    - by makerofthings7
    There is an add-in to the Task Parallel Library (TPL) called TPL Dataflow that allows a variety of data processing scenarios. It seems that there are some parallels to the SQL Stream Insight product, however since SQL's Stream Insight has some interesting licensing around it, and it has a better performance depending on what license I get... I found myself asking myself should I use TPL Dataflow and not have any licensing issues, and possibly better performance. Can anyone tell me if performance is a valid criteria for comparing SQL Stream Insight vs TPL Dataflow? What other criteria should I be looking at when comparing the two?

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