# Why does increasing the number of identical parallel operations increases each operation time?

**URL:** <https://discourse.julialang.org/t/why-does-increasing-the-number-of-identical-parallel-operations-increases-each-operation-time/57014>\
**Category:** Performance\
**Tags:** linearalgebra, distributed\
**Created:** [March 12, 2021, 11:08am UTC](https://discourse.julialang.org/t/why-does-increasing-the-number-of-identical-parallel-operations-increases-each-operation-time/57014 "2021-03-12T11:08:36Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [March 12, 2021, 1:33pm UTC](https://discourse.julialang.org/t/why-does-increasing-the-number-of-identical-parallel-operations-increases-each-operation-time/57014/5 "2021-03-12T13:33:53Z")

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> [@lmiq](#):
>
> think the problem can be associated with the fact that if one wants to generate a single sequence of random numbers, all threads will be accessing the same seed sequentially,

That’s not how `rand` works in Julia; it’s generating “independent” pseudorandom streams (i.e. starting from different seeds) on different processes or threads, so no synchronization is involved.

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