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Re: Value question (memory consumption) [message #29928 is a reply to message #29925]

Tue, 30 November 2010 13:51

dolik.rce
Messages: 1792
Registered: August 2008
Location: Czech Republic

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luzr wrote on Tue, 30 November 2010 13:21

andreincx wrote on Mon, 29 November 2010 16:57

Memory consumption is higher with U++ allocator. I've tested with USEMALLOC flag and the memory consumption was half, but has same behavior, only part of the memory is released.

Have you tested in debug or release (Optimal)? Those numbers look quite high to me (for U++ allocator). In debug mode, U++ inserts a LOT of debugging info into the heap, so the consumption is higher.

(Will have to test myself... Smile

I tested with optimal and U++ allocator.

luzr wrote on Tue, 30 November 2010 13:25

Yes, only "very large" (> app. 64KB) memory blocks are returned to OS. Rest is kept for later reuse. Anyway, this behaviour is pretty typical for most allocators, only maybe some of them have different threshold.

This explains it. Smile

SetCount() allocates all in one big block so it is returned, but Add() causes allocations of 1+2+4+8+...2^16B (that is up to 64KB) which are not returned (any further are bigger than 64KB and therefore returned). That should make ~128KB of non-returned blocks and that agrees exactly with what I measured for Vector<int>. For Vector<Value> it leaves more non-returned blocks probably because there are some additional allocations when constructing the Value...

Thanks for explanation,
Honza

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