How bad in LOH fragmentation on 64-bit systems

Question

Large object heap fragmentation is an obvious issue on 32 bit systems since the address space is relatively small and therefore you can run out of it and hit an OutOfMemoryException quite "quickly"

Since 64-bit address space is a lot larger, running out of addresses is less of an issue (for our scenario). Therefore, the main issue is how this affects the performance of the machine.

Is the free space in the LOH reserved but uncommitted, or does it stay committed? Even if it's committed, if it's unused wouldn't it be paged out and not actually take up physical memory?

In our specific scenario, we are less worried about hitting an OOM due to not having enough address space since this will: 1. Take a while and 2. Our service will be automatically restarted when this happens.

We are more concerned about the effect this will have on the overall performance of the machine we are running on.

Can anyone shed light on the subject?

Ed S. · Answer 1 · 2018-06-13T21:26:09.880

2

I try not to simply post direct links, but this page is probably not going anywhere and it explains the ins and outs of the LOH much better than I could here.

The Large Object Heap Uncovered

edited Jun 13 '18 at 21:26

answered Apr 19 '12 at 17:49

Ed S.

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Well, the page is gone somewhere! – Luke Marlin May 21 '18 at 16:37
@LukeMarlin: Haha so it has! – Ed S. Jun 06 '18 at 22:13
Do you know which issue it was by any chance? Seemed like an interesting read :) – Luke Marlin Jun 08 '18 at 08:33
@LukeMarlin: found it and updated post. Yes, it could move again.... but that's a long article, I'm not pasting it all here. – Ed S. Jun 13 '18 at 21:26

How bad in LOH fragmentation on 64-bit systems

1 Answers1