I've been trying to compare the memory footprint between a VB6 application and .Net application. Trying to determine what's the average difference between the two. The .Net code is for the most part a direct translation of the VB6 and for the most part has the same instructions as they would be programmed in C#. So while it's an apple t...
Knuth recently objected to 64-bit systems, saying that for programs which fit in 4 gigs of memory, "they effectively throw away half of the cache" because the pointers are twice as big as on a 32-bit system. My question is: can this problem be avoided by installing a 32-bit operating system on a 64-bit machine? And are there any bandw...
When using copy-on-write semantics to share memory among processes, how can you test if a memory page is writable or if it is marked as read-only? Can this be done by calling a specific assembler code, or reading a certain spot in memory, or through the OS's API? ...
Isn't the point of caching things in main memory to avoid the expensive disk i/o? If you're caching things in the swap space of a hard drive, how does that avoid disk i/o? ...
Is the memory space consumed by one object with 100 attributes the same as that of 100 objects, with one attribute each? How much memory is allocated for an object? How much additional space is used when adding an attribute? ...
I'm running my C++ program in gdb. I'm not real experienced with gdb, but I'm getting messages like: warning: HEAP[test.exe]: warning: Heap block at 064EA560 modified at 064EA569 past requested size of 1 How can I track down where this is happening at? Viewing the memory doesn't give me any clues. Thanks! ...
I'm currently writing a C# application that does a lot of digital signal processing, which involves a lot of small fine-tuned memory xfer operations. I wrote these routines using unsafe pointers and they seem to perform much better than I first thought. However, I want the app to be as fast as possible. Would I get any performance benef...
Vista's Resource Monitor includes a reading for "Hard Faults/sec". Is there an equivalent performance counter I can use in C# to get this reading? I've tried the "Page Faults/sec" under the memory category, but that appears to be something different. ...
Hi all, Does anyone know how much memory MyISAM and innoDB use? How does their memory usages compare when dealing with small tables vs. when dealing with bigger tables (up to 32 GB)? I know innoDB is heavier than MyISAM, but just how much more? Any help would be appreciated. Thanks, jb ...
I have some code in C# which has a com wrapper. This com wrapper is used in a native c++ application. The c++ code uses a method which returns an array of instances of a class from the c# library. The instances come from a SafeArray like so: for (long i =min; i<=max;i++) { IMyInterface *l = (IMyInterface *)malloc(sizeof IMyInterf...
We have Core2 machines (Dell T5400) with XP64. We observe that when running 32-bit processes, the performance of memcpy is on the order of 1.2GByte/s; however memcpy in a 64-bit process achieves about 2.2GByte/s (or 2.4GByte/s with the Intel compiler CRT's memcpy). While the initial reaction might be to just explain this away as due to...
Hello, I'm trying to take advantage of the constant memory, but I'm having a hard time figuring out how to nest arrays. What I have is an array of data that has counts for internal data but those are different for each entry. So based around the following simplified code I have two problems. First I don't know how to allocate the dat...
My huge 32-bit web services LLBLGen-based data access application is running alone on a dedicated 64-bit machine. Its physical memory consumption steadily grows up to approximately 2GB when the process releases almost all of the allocated space (up to 1,5GB) and continues to grow from that point again. There is no observable increase in ...
This is a question that was sparked by Rob Walker's answer here. Suppose I declare a class/struct like so: struct { char A; int B; char C; int D; }; Is it safe to assume that these members will be declared in exactly that order in memory, or is this a compiler dependent thing? I'm asking because I had always assumed...
Is it possible to share a single 'god' instance among everyone that links to this code, to be placed in a shared object? god* _god = NULL; extern "C" { int set_log_level(int level) { if(_god == NULL) return -1; _stb->log_level(level); return 0; } int god_init(){ if(_god == NULL){ _god = new god(); //Magic happ...
Most of my PHP apps have an ob_start at the beginning, runs through all the code, and then outputs the content, sometimes with some modifications, after everything is done. ob_start() //Business Logic, etc header->output(); echo apply_post_filter(ob_get_clean()); footer->output(); This ensures that PHP errors get displayed within the ...
What are the actual performance differences between Int64 and Int32 on 32 and 64 bit MS Windows? It would also be great to see some actual timings of Int64 vs Int32 on each of the two operating system variants. XP or Vista would also be interesting. See also this question about memcpy performance. ...
I've read some C++ books explaining how it's important to delete new-allocated memory. I have learnt some strategies like encapsuling the created object inside another object where its destructor will be called, etc, etc. However, if we have a singleton used during all the life of a program.. is it "really" important to delete it? As ...
SQL Server 2000: Is there a way to find out server memory / CPU parameters in Query Analyzer? ...
I need to configure Tomcat memory settings as part of a larger installation, so manually configuring tomcat with the configuration app after the fact is out of the question. I thought I could just throw the JVM memory settings into the JAVA_OPTS environment variable, but I'm testing that with jconsole to see if it works and it... doesn't...