Dr. Dobb's Journal - February 2008 - (Page 76) d02sutt_p3ma 12/11/07 9:32 AM Page 76 Effective Concurrency continued from page 74 hardware, so new features that are unthink- Figure 1: Illustrating Amdahl’s Law for s = p. able today will be possible on 16-core and 64core machines. In each case, it’s a matter of finding what previously unthinkable work could now be enabled by new machines, and enabling it—at first by gurus building their own libraries and frameworks, then by more and more developers as the tools became more mainstream. But don’t show me ray-traced bouncing balls or Mandelbrot graphics or the other usual embarrassingly parallel but niche (or downright useless) clichés—what we’re looking for are real ideas of real software we could imagine real kids and grandmothers using that could become possible on manycore machines. Here’s a quick potential example: Researchers know how to do speech recognition with near-human-quality accuracy in the lab, which is astonishingly good and would enable breakthrough user interfaces if it could be done that reliably in real time. The only trouble is that the software takes a week to run…on a single core. Can it be parallelized, and if so how many cores would we need to get a useful answer in a useful time? Bunches of smart people (and the smart money behind them) are investing hard work not only to find out the answer to that question, but also to find more questions like it. 3. Reduce s Using O(K) Concurrency Figure 2: Illustrating Gustafson’s Law, total work = s + Np. Figure 3: Applying Gustafson’s Law to p while also pipelining s. Just because something can’t be made O(N) parallel doesn’t mean it doesn’t contain any 76 Dr. Dobb’s Journal l www.ddj.com l February 2008 http://www.sparxsystems.com http://www.sparxsystems.com http://www.ddj.com
Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - February 2008 Dr. Dobb's Journal - February 2008 Contents Hmmmm Alia Vox Developer Diaries Developer’s Notebook South American Software Development Conversations Inside Visual Studio 2008 BibPort: Creating Bibliographic References Continuous LINQ The ZK Framework Static Testing C++ Code The Agile Edge Effective Concurrency Swaine’s Flames Dr. Dobb's Journal - February 2008 Dr. Dobb's Journal - February 2008 - Dr. Dobb's Journal - February 2008 (Page Cover1) Dr. Dobb's Journal - February 2008 - Dr. Dobb's Journal - February 2008 (Page Cover2) Dr. Dobb's Journal - February 2008 - Dr. Dobb's Journal - February 2008 (Page 1) Dr. Dobb's Journal - February 2008 - Dr. Dobb's Journal - February 2008 (Page 2) Dr. Dobb's Journal - February 2008 - Dr. Dobb's Journal - February 2008 (Page 3) Dr. Dobb's Journal - February 2008 - Contents (Page 4) Dr. Dobb's Journal - February 2008 - Contents (Page 5) Dr. Dobb's Journal - February 2008 - Hmmmm (Page 6) Dr. Dobb's Journal - February 2008 - Hmmmm (Page 7) Dr. Dobb's Journal - February 2008 - Hmmmm (Page 8) Dr. Dobb's Journal - February 2008 - Hmmmm (Page 9) Dr. Dobb's Journal - February 2008 - Alia Vox (Page 10) Dr. Dobb's Journal - February 2008 - Alia Vox (Page 11) Dr. Dobb's Journal - February 2008 - Developer Diaries (Page 12) Dr. Dobb's Journal - February 2008 - Developer Diaries (Page 13) Dr. Dobb's Journal - February 2008 - Developer’s Notebook (Page 14) Dr. Dobb's Journal - February 2008 - Developer’s Notebook (Page 15) Dr. Dobb's Journal - February 2008 - South American Software Development (Page 16) Dr. Dobb's Journal - February 2008 - South American Software Development (Page 17) Dr. Dobb's Journal - February 2008 - South American Software Development (Page 18) Dr. Dobb's Journal - February 2008 - South American Software Development (Page 19) Dr. Dobb's Journal - February 2008 - Conversations (Page 20) Dr. Dobb's Journal - February 2008 - Conversations (Page 21) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 22) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 23) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 24) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 25) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 26) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 27) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 28) Dr. Dobb's Journal - February 2008 - Inside Visual Studio 2008 (Page 29) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 30) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 31) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 32) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 33) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 34) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 35) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 36) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 37) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 38) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 39) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 40) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 41) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 42) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 43) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 44) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 45) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 46) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 47) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 48) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 49) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 50) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 51) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 52) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 53) Dr. Dobb's Journal - February 2008 - BibPort: Creating Bibliographic References (Page 54) Dr. Dobb's Journal - February 2008 - Continuous LINQ (Page 55) Dr. Dobb's Journal - February 2008 - Continuous LINQ (Page 56) Dr. Dobb's Journal - February 2008 - Continuous LINQ (Page 57) Dr. Dobb's Journal - February 2008 - Continuous LINQ (Page 58) Dr. Dobb's Journal - February 2008 - Continuous LINQ (Page 59) Dr. Dobb's Journal - February 2008 - The ZK Framework (Page 60) Dr. Dobb's Journal - February 2008 - The ZK Framework (Page 61) Dr. Dobb's Journal - February 2008 - The ZK Framework (Page 62) Dr. Dobb's Journal - February 2008 - The ZK Framework (Page 63) Dr. Dobb's Journal - February 2008 - The ZK Framework (Page 64) Dr. Dobb's Journal - February 2008 - The ZK Framework (Page 65) Dr. Dobb's Journal - February 2008 - Static Testing C++ Code (Page 66) Dr. Dobb's Journal - February 2008 - Static Testing C++ Code (Page 67) Dr. Dobb's Journal - February 2008 - Static Testing C++ Code (Page 68) Dr. Dobb's Journal - February 2008 - Static Testing C++ Code (Page 69) Dr. Dobb's Journal - February 2008 - Static Testing C++ Code (Page 70) Dr. Dobb's Journal - February 2008 - The Agile Edge (Page 71) Dr. Dobb's Journal - February 2008 - The Agile Edge (Page 72) Dr. Dobb's Journal - February 2008 - The Agile Edge (Page 73) Dr. Dobb's Journal - February 2008 - Effective Concurrency (Page 74) Dr. Dobb's Journal - February 2008 - Effective Concurrency (Page 75) Dr. Dobb's Journal - February 2008 - Effective Concurrency (Page 76) Dr. Dobb's Journal - February 2008 - Effective Concurrency (Page 77) Dr. Dobb's Journal - February 2008 - Effective Concurrency (Page 78) Dr. Dobb's Journal - February 2008 - Effective Concurrency (Page 79) Dr. Dobb's Journal - February 2008 - Swaine’s Flames (Page 80) Dr. Dobb's Journal - February 2008 - Swaine’s Flames (Page Cover3) Dr. Dobb's Journal - February 2008 - Swaine’s Flames (Page Cover4)
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