Group items tagged Profile - Coders

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.NET Memory Profiler - 0 views

shared by Joel Bennett on 13 Feb 09 - Cached

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Fabulous Adventures In Coding : The Stack Is An Implementation Detail, Part One - 0 views

blogs.msdn.com/...-an-implementation-detail.aspx clr cli .NETGeneral c# memory allocation

shared by Matteo Spreafico on 14 Aug 09 - Cached

Almost every article I see that describes the difference between value types and reference types explains in (frequently incorrect) detail about what “the stack” is and how the major difference between value types and reference types is that value types go on the stack.
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I find this characterization of a value type based on its implementation details rather than its observable characteristics to be both confusing and unfortunate. Surely the most relevant fact about value types is not the implementation detail of how they are allocated, but rather the by-design semantic meaning of “value type”, namely that they are always copied “by value”.
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Of course, the simplistic statement I described is not even true. As the MSDN documentation correctly notes, value types are allocated on the stack sometimes. For example, the memory for an integer field in a class type is part of the class instance’s memory, which is allocated on the heap.
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As long as the implementation maintains the semantics guaranteed by the specification, it can choose any strategy it likes for generating efficient code
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That Windows typically does so, and that this one-meg array is an efficient place to store small amounts of short-lived data is great, but it’s not a requirement that an operating system provide such a structure, or that the jitter use it. The jitter could choose to put every local “on the heap” and live with the performance cost of doing so, as long as the value type semantics were maintained
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I would only be making that choice if profiling data showed that there was a large, real-world-customer-impacting performance problem directly mitigated by using value types. Absent such data, I’d always make the choice of value type vs reference type based on whether the type is semantically representing a value or semantically a reference to something.
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Userprofile Management - 0 views

www.eblogin.com/...sp-Userprofile.aspx User Profile Sharepoint Internet Computer Information Technology 2010

shared by Blog city on 21 Feb 11 - No Cached

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Programming as if Performance Mattered, by James Hague [2004-04-04] - 3 views

dadgum.com/performance.html optimization low-level erlang

shared by Fabien Cadet on 01 Nov 09 - Cached

I frequently see bare queries from programmers in discussion forums, especially from new programmers, who are worried about performance. These worries often stem from popular notions about what operations are "slow." Division. Square roots. Mispredicted branches. Cache unfriendly data structures.
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Inevitably someone chimes in that making out-of-context assumptions, especially without profiling, is a bad idea. And they're right.
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The golden rule of programming has always been that clarity and correctness matter much more than the utmost speed. Very few people will argue with that. And yet do we really believe it? If we did, then 99% of all programs would be written in something like Python. Or Erlang.
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At the same time, such concerns and advice seem to remain constant despite rapid advances in hardware.
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That tempting, enticing, puzzle-solving activity called "optimization," it hasn't gone away either.
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Only now the process is on a different level. It isn't machine level twiddling and cycle counting, but it isn't simply mathematical analysis of algorithms either.
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The big difference is that the code changes I made are substantially safer than running a program and having it silently hang the system. All array accesses are bounds-checked. There's no way to accidentally overwrite a data structure. There's no way to create a memory leak.
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Really, this is what those cycle-counting programmers from 1985 dreamed of.
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Fabien Cadet on 01 Nov 09

« I frequently see bare queries from programmers in discussion forums, especially from new programmers, who are worried about performance. These worries often stem from popular notions about what operations are "slow." Division. Square roots. Mispredicted branches. Cache unfriendly data structures. »

<div class="cArrow"> </div><div class="cContentInner">« I frequently see bare queries from programmers in discussion forums, especially from new programmers, who are worried about performance. These worries often stem from popular notions about what operations are "slow." Division. Square roots. Mispredicted branches. Cache unfriendly data structures. »</div>

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