--- title: How fast can you open 1000 files? – Daniel Lemire's blog description: Jarred Sumner noted on X that macOS has slow file opening due to thread contention. Daniel Lemire tested this by writing a C++ program to open 1000 files using... canonical: https://daily.dev/posts/how-fast-can-you-open-1000-files-daniel-lemire-s-blog-vwps5mrkv twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: How fast can you open 1000 files? – Daniel Lemire's blog | daily.dev og:description: Jarred Sumner noted on X that macOS has slow file opening due to thread contention. Daniel Lemire tested this by writing a C++ program to open 1000 files using... og:url: https://daily.dev/posts/how-fast-can-you-open-1000-files-daniel-lemire-s-blog-vwps5mrkv og:image: https://api.daily.dev/og/posts/vwps5mRKV.png og:image:alt: How fast can you open 1000 files? – Daniel Lemire's blog og:image:width: 1200 og:image:height: 630 og:locale: en --- [Daniel Lemire](https://daily.dev/sources/lemire) [Read post](https://api.daily.dev/r/vwps5mRKV) # [How fast can you open 1000 files? – Daniel Lemire's blog](https://api.daily.dev/r/vwps5mRKV "Go to post") Jarred Sumner noted on X that macOS has slow file opening due to thread contention. Daniel Lemire tested this by writing a C++ program to open 1000 files using varying thread counts on an Apple M2 laptop and a big x64 Linux server. Results showed macOS is slower despite better hardware, while Linux performed better overall. More threads didn't always mean better performance, and thread pools sometimes helped on the bigger machine. [#c++](/tags/c%2B%2B "Check all #c++ posts")[#linux](/tags/linux "Check all #linux posts")[#mac](/tags/mac "Check all #mac posts")[#performance](/tags/performance "Check all #performance posts") Mar 01, 2025•3m read time•From [lemire.me](https://api.daily.dev/r/vwps5mRKV "lemire.me") [](https://api.daily.dev/r/vwps5mRKV "Go to post") 30 Impressions8 Upvotes Comment Bookmark Copy Share your thoughtsPost [](https://daily.dev/sources/lemire) [Daniel Lemire](https://daily.dev/sources/lemire "https://daily.dev/sources/lemire") Authored by Daniel Lemire, a computer science professor and researcher, this blog covers a wide rang... Read more 21 Followers • 127 Upvotes #### Would you recommend this post? 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