{"id":361865,"date":"2017-02-06T14:34:36","date_gmt":"2017-02-06T22:34:36","guid":{"rendered":"https:\/\/www.microsoft.com\/en-us\/research\/?post_type=msr-research-item&#038;p=361865"},"modified":"2018-10-16T20:06:38","modified_gmt":"2018-10-17T03:06:38","slug":"designing-chip-networks-throughput-accelerators","status":"publish","type":"msr-research-item","link":"https:\/\/www.microsoft.com\/en-us\/research\/publication\/designing-chip-networks-throughput-accelerators\/","title":{"rendered":"Designing On-Chip Networks for Throughput Accelerators"},"content":{"rendered":"<p>As the number of cores and threads in throughput accelerators such as Graphics Processing Units (GPU) increases, so does the importance of on-chip interconnection network design. This article explores throughput-effective Network-on-Chips (NoC) for future compute accelerators that employ Bulk-Synchronous Parallel (BSP) programming models such as CUDA and OpenCL. A hardware optimization is \u201cthroughput effective\u201d if it improves parallel application-level performance per unit chip area. We evaluate performance of future looking workloads using detailed closed-loop simulations modeling compute nodes, NoC, and the DRAM memory system. We start from a mesh design with bisection bandwidth balanced to off-chip demand. Accelerator workloads tend to demand high off-chip memory bandwidth which results in a many-to-few traffic pattern when coupled with expected technology constraints of slow growth in pins-per-chip. Leveraging these observations we reduce NoC area by proposing a \u201ccheckerboard\u201d NoC which alternates between conventional\u00a0<i>full<\/i>\u00a0routers and\u00a0<i>half<\/i>\u00a0routers with limited connectivity. Next, we show that increasing network terminal bandwidth at the nodes connected to DRAM controllers alleviates a significant fraction of the remaining imbalance resulting from the many-to-few traffic pattern. Furthermore, we propose a \u201cdouble checkerboard inverted\u201d NoC organization which takes advantage of channel slicing to reduce area while maintaining the performance improvements of the aforementioned techniques. This organization also has a simpler routing mechanism and improves average application throughput per unit area by 24.3%.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>As the number of cores and threads in throughput accelerators such as Graphics Processing Units (GPU) increases, so does the importance of on-chip interconnection network design. This article explores throughput-effective Network-on-Chips (NoC) for future compute accelerators that employ Bulk-Synchronous Parallel (BSP) programming models such as CUDA and OpenCL. A hardware optimization is \u201cthroughput effective\u201d if [&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":"ACM","msr_publisher_other":"","msr_booktitle":"","msr_chapter":"","msr_edition":"ACM Transactions on Architecture and Code Optimization (TACO)","msr_editors":"","msr_how_published":"","msr_isbn":"","msr_issue":"","msr_journal":"ACM Transactions on Architecture and Code Optimization (TACO)","msr_number":"","msr_organization":"","msr_pages_string":"35","msr_page_range_start":"35","msr_page_range_end":"","msr_series":"","msr_volume":"10","msr_copyright":"","msr_conference_name":"","msr_doi":"https:\/\/doi.org\/10.1145\/2512429","msr_arxiv_id":"","msr_s2_paper_id":"","msr_mag_id":"","msr_pubmed_id":"","msr_other_authors":"","msr_other_contributors":"","msr_speaker":"","msr_award":"","msr_affiliation":"","msr_institution":"","msr_host":"","msr_version":"","msr_duration":"","msr_original_fields_of_study":"","msr_release_tracker_id":"","msr_s2_match_type":"","msr_citation_count_updated":"","msr_published_date":"2013-09-01","msr_highlight_text":"","msr_notes":"","msr_longbiography":"","msr_publicationurl":"http:\/\/dl.acm.org\/citation.cfm?doid=2509420.2512429","msr_external_url":"","msr_secondary_video_url":"","msr_conference_url":"","msr_journal_url":"","msr_s2_pdf_url":"","msr_year":0,"msr_citation_count":0,"msr_influential_citations":0,"msr_reference_count":0,"msr_s2_match_confidence":0,"msr_microsoftintellectualproperty":true,"msr_s2_open_access":false,"msr_s2_author_ids":[],"msr_pub_ids":[],"msr_hide_image_in_river":0,"footnotes":""},"msr-research-highlight":[],"research-area":[13552,13547],"msr-publication-type":[193715],"msr-publisher":[],"msr-focus-area":[],"msr-locale":[268875],"msr-post-option":[],"msr-field-of-study":[],"msr-conference":[],"msr-journal":[],"msr-impact-theme":[],"msr-pillar":[],"class_list":["post-361865","msr-research-item","type-msr-research-item","status-publish","hentry","msr-research-area-hardware-devices","msr-research-area-systems-and-networking","msr-locale-en_us"],"msr_publishername":"ACM","msr_edition":"ACM Transactions on Architecture and Code Optimization (TACO)","msr_affiliation":"","msr_published_date":"2013-09-01","msr_host":"","msr_duration":"","msr_version":"","msr_speaker":"","msr_other_contributors":"","msr_booktitle":"","msr_pages_string":"35","msr_chapter":"","msr_isbn":"","msr_journal":"ACM Transactions on Architecture and Code Optimization (TACO)","msr_volume":"10","msr_number":"","msr_editors":"","msr_series":"","msr_issue":"","msr_organization":"","msr_how_published":"","msr_notes":"","msr_highlight_text":"","msr_release_tracker_id":"","msr_original_fields_of_study":"","msr_download_urls":"","msr_external_url":"","msr_secondary_video_url":"","msr_longbiography":"","msr_microsoftintellectualproperty":1,"msr_main_download":"","msr_publicationurl":"http:\/\/dl.acm.org\/citation.cfm?doid=2509420.2512429","msr_doi":"https:\/\/doi.org\/10.1145\/2512429","msr_publication_uploader":[{"type":"url","title":"http:\/\/dl.acm.org\/citation.cfm?doid=2509420.2512429","viewUrl":false,"id":false,"label_id":0},{"type":"doi","title":"https:\/\/doi.org\/10.1145\/2512429","viewUrl":false,"id":false,"label_id":0}],"msr_related_uploader":"","msr_citation_count":0,"msr_citation_count_updated":"","msr_s2_paper_id":"","msr_influential_citations":0,"msr_reference_count":0,"msr_arxiv_id":"","msr_s2_author_ids":[],"msr_s2_open_access":false,"msr_s2_pdf_url":null,"msr_attachments":[{"id":0,"url":"http:\/\/dl.acm.org\/citation.cfm?doid=2509420.2512429"}],"msr-author-ordering":[{"type":"user_nicename","value":"aliba","user_id":30943,"rest_url":"https:\/\/www.microsoft.com\/en-us\/research\/wp-json\/microsoft-research\/v1\/researchers?person=aliba"},{"type":"text","value":"John Kim","user_id":0,"rest_url":false},{"type":"text","value":"Tor M. 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