# Very different performance in different computers due to garbage collection?

**URL:** <https://discourse.julialang.org/t/very-different-performance-in-different-computers-due-to-garbage-collection/87563>\
**Category:** Performance\
**Tags:** question, performance, garbage-collection, speed-optimization\
**Created:** [September 21, 2022, 10:00am UTC](https://discourse.julialang.org/t/very-different-performance-in-different-computers-due-to-garbage-collection/87563 "2022-09-21T10:00:41Z")\
**Posts on this page:** 1\
**Showing post:** 23

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**Author:** ![jeff.bezanson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jeff.bezanson/32/48_2.png) [@jeff.bezanson](https://discourse.julialang.org/u/jeff.bezanson)\
**Post date:** [September 21, 2022, 10:43pm UTC](https://discourse.julialang.org/t/very-different-performance-in-different-computers-due-to-garbage-collection/87563/23 "2022-09-21T22:43:56Z")

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Thanks! How many threads are you using? Does the problem happen with one thread?  
In the desktop profile, we mostly see threads waiting for gc to finish, but it’s not clear whether that’s a cause or an effect. For example maybe using the CPU pause instruction in jl\_safepoint\_wait\_gc is causing the kernel to de-schedule us for a long time on one system.

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