{"id":152307,"date":"1993-09-01T00:00:00","date_gmt":"1993-09-01T00:00:00","guid":{"rendered":"https:\/\/www.microsoft.com\/en-us\/research\/msr-research-item\/false-sharing-and-its-effect-on-shared-memory-performance\/"},"modified":"2018-10-16T22:06:14","modified_gmt":"2018-10-17T05:06:14","slug":"false-sharing-and-its-effect-on-shared-memory-performance","status":"publish","type":"msr-research-item","link":"https:\/\/www.microsoft.com\/en-us\/research\/publication\/false-sharing-and-its-effect-on-shared-memory-performance\/","title":{"rendered":"False Sharing and Its Effect on Shared Memory Performance"},"content":{"rendered":"<div class=\"asset-content\">\n<p>False sharing occurs when processors in a shared-memory parallel system make references to different data objects within the same coherence block (cache line or page), thereby inducing unnecessary coherence operations. False sharing is widely believed to be a serious problem for parallel program performance, but a precise definition and quantification of the problem has proven to be elusive. We explain why. In the process, we present a variety of possible definitions for false sharing, and discuss the merits and drawbacks of each. Our discussion is based on experience gained during a four-year study of multiprocessor memory architecture and its effect on the behavior of applications in a sixteen-program suite. Using trace-based simulation, we present experimental evidence to support the claim that false sharing is a serious problem. Unfortunately, we find that the various computationally tractable approaches to quantifying the problem are either heuristic in nature, or fail to agree with intuition.<\/p>\n<\/div>\n<p><!-- .asset-content --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>False sharing occurs when processors in a shared-memory parallel system make references to different data objects within the same coherence block (cache line or page), thereby inducing unnecessary coherence operations. False sharing is widely believed to be a serious problem for parallel program performance, but a precise definition and quantification of the problem has proven [&hellip;]<\/p>\n","protected":false},"featured_media":0,"template":"","meta":{"msr-url-field":"","msr-podcast-episode":"","msrModifiedDate":"","msrModifiedDateEnabled":false,"ep_exclude_from_search":false,"_classifai_error":"","msr-author-ordering":null,"msr_publishername":"Advanced Computing Systems Association","msr_publisher_other":"","msr_booktitle":"","msr_chapter":"","msr_edition":"","msr_editors":"","msr_how_published":"","msr_isbn":"","msr_issue":"","msr_journal":"","msr_number":"MSR-TR-93-01","msr_organization":"","msr_pages_string":"16","msr_page_range_start":"16","msr_page_range_end":"","msr_series":"","msr_volume":"","msr_copyright":"","msr_conference_name":"","msr_doi":"","msr_arxiv_id":"","msr_s2_paper_id":"","msr_mag_id":"","msr_pubmed_id":"","msr_other_authors":"William J. Bolosky, Michael L. 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