{"id":3339,"date":"2025-12-08T00:00:00","date_gmt":"2025-12-08T00:00:00","guid":{"rendered":"https:\/\/lp.szlogic.cn\/glossary\/what-is-direct-memory-access-dma-explained\/"},"modified":"2026-06-09T09:45:33","modified_gmt":"2026-06-09T09:45:33","slug":"what-is-direct-memory-access-dma-explained","status":"publish","type":"post","link":"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/what-is-direct-memory-access-dma-explained","title":{"rendered":"Truy c\u1eadp b\u1ed9 nh\u1edb tr\u1ef1c ti\u1ebfp (DMA) l\u00e0 g\u00ec? Gi\u1ea3i th\u00edch DMA"},"content":{"rendered":"<figure class=\"wp-block-image aligncenter size-large\"><img fetchpriority=\"high\" decoding=\"async\" width=\"1408\" height=\"768\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/296a5f4af1ba4c899c76c6ac9b8d0a08.jpg\" alt=\"What Is Direct Memory Access (DMA)?\" class=\"wp-image-3336\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/296a5f4af1ba4c899c76c6ac9b8d0a08.jpg 1408w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/296a5f4af1ba4c899c76c6ac9b8d0a08-300x164.jpg 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/296a5f4af1ba4c899c76c6ac9b8d0a08-1024x559.jpg 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/296a5f4af1ba4c899c76c6ac9b8d0a08-768x419.jpg 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/296a5f4af1ba4c899c76c6ac9b8d0a08-18x10.jpg 18w\" sizes=\"(max-width: 1408px) 100vw, 1408px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Trong th\u1ebf gi\u1edbi \u0111i\u1ec7n to\u00e1n, t\u1ed1c \u0111\u1ed9 l\u00e0 y\u1ebfu t\u1ed1 quy\u1ebft \u0111\u1ecbnh. D\u00f9 b\u1ea1n \u0111ang ch\u01a1i game, ph\u00e1t tr\u1ef1c tuy\u1ebfn video 4K hay x\u1eed l\u00fd c\u00e1c t\u1eadp d\u1eef li\u1ec7u kh\u1ed5ng l\u1ed3 trong trung t\u00e2m d\u1eef li\u1ec7u, vi\u1ec7c di chuy\u1ec3n d\u1eef li\u1ec7u m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3 l\u00e0 \u0111i\u1ec1u t\u1ed1i quan tr\u1ecdng. N\u1eb1m \u1edf trung t\u00e2m c\u1ee7a qu\u00e1 tr\u00ecnh truy\u1ec1n d\u1eef li\u1ec7u t\u1ed1c \u0111\u1ed9 cao n\u00e0y l\u00e0 m\u1ed9t c\u00f4ng ngh\u1ec7 then ch\u1ed1t nh\u01b0ng th\u01b0\u1eddng b\u1ecb b\u1ecf qua: <strong>Truy c\u1eadp B\u1ed9 nh\u1edb Tr\u1ef1c ti\u1ebfp (DMA)<\/strong>. B\u00e0i vi\u1ebft n\u00e0y s\u1ebd l\u00e0m r\u00f5 kh\u00e1i ni\u1ec7m DMA, gi\u1ea3i th\u00edch c\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng, l\u00fd do v\u00ec sao n\u00f3 kh\u00f4ng th\u1ec3 thi\u1ebfu \u0111\u1ed1i v\u1edbi hi\u1ec7u n\u0103ng hi\u1ec7n \u0111\u1ea1i v\u00e0 vai tr\u00f2 c\u1ee7a n\u00f3 trong ph\u1ea7n c\u1ee9ng ti\u00ean ti\u1ebfn nh\u01b0 thi\u1ebft b\u1ecb t\u1ed1c \u0111\u1ed9 cao <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-25432-optics-transceivers-sfp-modules.htm\"><strong>b\u1ed9 thu ph\u00e1t quang<\/strong><\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 Nh\u1eefng \u0111i\u1ec3m ch\u00ednh c\u1ea7n ghi nh\u1edb<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p><strong>Truy c\u1eadp B\u1ed9 nh\u1edb Tr\u1ef1c ti\u1ebfp (DMA)<\/strong> cho ph\u00e9p c\u00e1c thi\u1ebft b\u1ecb di chuy\u1ec3n d\u1eef li\u1ec7u tr\u1ef1c ti\u1ebfp v\u00e0o b\u1ed9 nh\u1edb. CPU kh\u00f4ng c\u1ea7n ph\u1ea3i h\u1ed7 tr\u1ee3. \u0110i\u1ec1u n\u00e0y gi\u00fap m\u00e1y t\u00ednh c\u1ee7a b\u1ea1n ho\u1ea1t \u0111\u1ed9ng nhanh h\u01a1n v\u00e0 hi\u1ec7u qu\u1ea3 h\u01a1n.<\/p><\/li><li><p>C\u00f3 nhi\u1ec1u lo\u1ea1i DMA kh\u00e1c nhau. Ch\u1ebf \u0111\u1ed9 \u0110\u1ee3t (Burst Mode) v\u00e0 Chi\u1ebfm Chu k\u1ef3 (Cycle Stealing) l\u00e0 nh\u1eefng v\u00ed d\u1ee5. M\u1ed7i lo\u1ea1i ph\u1ee5c v\u1ee5 c\u00e1c nhu c\u1ea7u truy\u1ec1n d\u1eef li\u1ec7u kh\u00e1c nhau. \u0110i\u1ec1u n\u00e0y gi\u00fap b\u1ea1n l\u1ef1a ch\u1ecdn lo\u1ea1i ph\u00f9 h\u1ee3p nh\u1ea5t cho thi\u1ebft b\u1ecb c\u1ee7a m\u00ecnh.<\/p><\/li><li><p>DMA gi\u1ea3m kh\u1ed1i l\u01b0\u1ee3ng c\u00f4ng vi\u1ec7c m\u00e0 CPU ph\u1ea3i th\u1ef1c hi\u1ec7n. Nh\u1edd \u0111\u00f3, m\u00e1y t\u00ednh c\u1ee7a b\u1ea1n c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n nhi\u1ec1u t\u00e1c v\u1ee5 c\u00f9ng l\u00fac m\u1ed9t c\u00e1ch m\u01b0\u1ee3t m\u00e0 h\u01a1n. N\u00f3 c\u0169ng h\u1ed7 tr\u1ee3 hi\u1ec7u qu\u1ea3 cho ch\u01a1i game, ph\u00e1t tr\u1ef1c tuy\u1ebfn video v\u00e0 ch\u1ec9nh s\u1eeda \u00e2m thanh.<\/p><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 Kh\u00e1i ni\u1ec7m c\u1ed1t l\u00f5i: B\u1ecf qua \u0111i\u1ec3m ngh\u1ebdn CPU<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">H\u00e3y t\u01b0\u1edfng t\u01b0\u1ee3ng m\u1ed9t l\u00f4 s\u00e1ch l\u1edbn (d\u1eef li\u1ec7u) \u0111\u01b0\u1ee3c giao \u0111\u1ebfn m\u1ed9t th\u01b0 vi\u1ec7n (m\u00e1y t\u00ednh c\u1ee7a b\u1ea1n). N\u1ebfu kh\u00f4ng c\u00f3 DMA, th\u1ee7 th\u01b0 tr\u01b0\u1edfng (CPU) ph\u1ea3i t\u1ef1 tay nh\u1eadn t\u1eebng th\u00f9ng h\u00e0ng, m\u1edf ra v\u00e0 \u0111\u1eb7t t\u1eebng cu\u1ed1n s\u00e1ch l\u00ean \u0111\u00fang k\u1ec7 (RAM). Vi\u1ec7c n\u00e0y c\u1ef1c k\u1ef3 k\u00e9m hi\u1ec7u qu\u1ea3 v\u00e0 khi\u1ebfn th\u1ee7 th\u01b0 b\u1ecb chi\u1ebfm d\u1ee5ng b\u1edfi nh\u1eefng c\u00f4ng vi\u1ec7c nh\u00e0m ch\u00e1n.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Truy c\u1eadp B\u1ed9 nh\u1edb Tr\u1ef1c ti\u1ebfp<\/strong> gi\u1ed1ng nh\u01b0 thu\u00ea m\u1ed9t \u0111\u1ed9i logistics chuy\u00ean bi\u1ec7t. Th\u1ee7 th\u01b0 ch\u1ec9 c\u1ea7n cung c\u1ea5p \u0111\u1ecba ch\u1ec9 giao h\u00e0ng v\u00e0 h\u01b0\u1edbng d\u1eabn. \u0110\u1ed9i n\u00e0y sau \u0111\u00f3 t\u1ef1 ch\u1ee7 x\u1eed l\u00fd to\u00e0n b\u1ed9 qu\u00e1 tr\u00ecnh chuy\u1ec3n giao, gi\u1ea3i ph\u00f3ng th\u1ee7 th\u01b0 \u0111\u1ec3 th\u1ef1c hi\u1ec7n nh\u1eefng nhi\u1ec7m v\u1ee5 quan tr\u1ecdng h\u01a1n nh\u01b0 ch\u1ea1y c\u00e1c \u1ee9ng d\u1ee5ng ph\u1ee9c t\u1ea1p.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">V\u1ec1 m\u1eb7t k\u1ef9 thu\u1eadt, <strong>DMA<\/strong> l\u00e0 m\u1ed9t t\u00ednh n\u0103ng cho ph\u00e9p m\u1ed9t s\u1ed1 ph\u00e2n h\u1ec7 ph\u1ea7n c\u1ee9ng nh\u1ea5t \u0111\u1ecbnh (nh\u01b0 \u1ed5 l\u01b0u tr\u1eef, card m\u1ea1ng ho\u1eb7c card \u0111\u1ed3 h\u1ecda) truy c\u1eadp b\u1ed9 nh\u1edb h\u1ec7 th\u1ed1ng ch\u00ednh (RAM) m\u1ed9t c\u00e1ch \u0111\u1ed9c l\u1eadp, m\u00e0 kh\u00f4ng c\u1ea7n s\u1ef1 can thi\u1ec7p li\u00ean t\u1ee5c t\u1eeb <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/what-is-cpu-central-processing-unit\/\"><strong>\u0110\u01a1n V\u1ecb X\u1eed L\u00fd Trung T\u00e2m (CPU)<\/strong><\/a>. \u0110i\u1ec1u n\u00e0y gi\u1ea3m t\u1ea3i cho CPU kh\u1ecfi nhi\u1ec7m v\u1ee5 n\u1eb7ng n\u1ec1 l\u00e0 sao ch\u00e9p t\u1eebng byte d\u1eef li\u1ec7u, t\u1eeb \u0111\u00f3 c\u1ea3i thi\u1ec7n \u0111\u00e1ng k\u1ec3 hi\u1ec7u su\u1ea5t v\u00e0 hi\u1ec7u qu\u1ea3 t\u1ed5ng th\u1ec3 c\u1ee7a h\u1ec7 th\u1ed1ng.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 DMA ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o? Ph\u00e2n t\u00edch t\u1eebng b\u01b0\u1edbc<\/strong><\/h2>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/349a78afb11b4e61b2a2302ccb13c0cc.webp\" alt=\"Direct Memory Access\" class=\"wp-image-3337\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/349a78afb11b4e61b2a2302ccb13c0cc.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/349a78afb11b4e61b2a2302ccb13c0cc-300x178.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/349a78afb11b4e61b2a2302ccb13c0cc-1024x608.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/349a78afb11b4e61b2a2302ccb13c0cc-768x456.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/349a78afb11b4e61b2a2302ccb13c0cc-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Qu\u00e1 tr\u00ecnh DMA \u0111\u01b0\u1ee3c qu\u1ea3n l\u00fd b\u1edfi m\u1ed9t <strong>B\u1ed9 \u0111i\u1ec1u khi\u1ec3n DMA (DMAC)<\/strong>, th\u01b0\u1eddng \u0111\u01b0\u1ee3c t\u00edch h\u1ee3p s\u1eb5n trong c\u00e1c chipset hi\u1ec7n \u0111\u1ea1i ho\u1eb7c ngay trong c\u00e1c thi\u1ebft b\u1ecb \u0111\u1ea7u v\u00e0o\/\u0111\u1ea7u ra (I\/O). D\u01b0\u1edbi \u0111\u00e2y l\u00e0 tr\u00ecnh t\u1ef1 \u0111\u01a1n gi\u1ea3n h\u00f3a:<\/p>\n\n\n\n<ol class=\"wp-block-list\" >\n<li><p style=\"margin: 0px;\"><strong>Thi\u1ebft l\u1eadp b\u1edfi CPU:<\/strong> CPU l\u1eadp tr\u00ecnh DMAC. N\u00f3 cung c\u1ea5p <strong>\u0111\u1ecba ch\u1ec9 ngu\u1ed3n<\/strong> (v\u00ed d\u1ee5: v\u1ecb tr\u00ed tr\u00ean m\u1ed9t \u1ed5 SSD), <strong>\u0111\u1ecba ch\u1ec9 \u0111\u00edch<\/strong> (m\u1ed9t kh\u1ed1i trong RAM) v\u00e0 <strong>l\u01b0\u1ee3ng d\u1eef li\u1ec7u<\/strong> c\u1ea7n truy\u1ec1n.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Y\u00eau c\u1ea7u truy\u1ec1n:<\/strong> Thi\u1ebft b\u1ecb ngo\u1ea1i vi (v\u00ed d\u1ee5: m\u1ed9t <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/470377.htm\"><strong>LINK-PP 400G QSFP-DD DR4<\/strong><\/a> b\u1ed9 thu ph\u00e1t quang \u0111ang nh\u1eadn d\u1eef li\u1ec7u m\u1ea1ng) b\u00e1o hi\u1ec7u r\u1eb1ng n\u00f3 \u0111\u00e3 s\u1eb5n s\u00e0ng \u0111\u1ec3 truy\u1ec1n d\u1eef li\u1ec7u.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>DMA \u0111\u1ea3m nh\u1eadn:<\/strong> DMAC y\u00eau c\u1ea7u quy\u1ec1n ki\u1ec3m so\u00e1t bus h\u1ec7 th\u1ed1ng t\u1eeb CPU (qu\u00e1 tr\u00ecnh n\u00e0y g\u1ecdi l\u00e0 <em>ph\u00e2n b\u1ed5 bus<\/em>). Khi \u0111\u01b0\u1ee3c c\u1ea5p quy\u1ec1n, CPU t\u1ea1m th\u1eddi b\u1ecb ng\u1eaft k\u1ebft n\u1ed1i kh\u1ecfi bus.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Di chuy\u1ec3n d\u1eef li\u1ec7u tr\u1ef1c ti\u1ebfp:<\/strong> DMAC qu\u1ea3n l\u00fd vi\u1ec7c truy\u1ec1n d\u1eef li\u1ec7u tr\u1ef1c ti\u1ebfp gi\u1eefa thi\u1ebft b\u1ecb v\u00e0 RAM. Trong th\u1eddi gian n\u00e0y, CPU c\u00f3 th\u1ec3 ti\u1ebfp t\u1ee5c th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh kh\u00e1c.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Ho\u00e0n t\u1ea5t v\u00e0 ng\u1eaft:<\/strong> Khi qu\u00e1 tr\u00ecnh truy\u1ec1n ho\u00e0n t\u1ea5t, DMAC gi\u1ea3i ph\u00f3ng bus v\u00e0 g\u1eedi m\u1ed9t <strong>t\u00edn hi\u1ec7u ng\u1eaft<\/strong> t\u1edbi CPU. L\u00fac n\u00e0y, CPU bi\u1ebft d\u1eef li\u1ec7u \u0111\u00e3 s\u1eb5n s\u00e0ng \u0111\u1ec3 x\u1eed l\u00fd.<\/p><\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Hai ch\u1ebf \u0111\u1ed9 ch\u00ednh chi ph\u1ed1i c\u00e1ch DMAC t\u01b0\u01a1ng t\u00e1c v\u1edbi bus:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px;\"><strong>Chi\u1ebfm chu k\u1ef3 (Cycle Stealing):<\/strong> DMAC \u201cchi\u1ebfm\u201d c\u00e1c chu k\u1ef3 bus t\u1eeb CPU khi CPU kh\u00f4ng s\u1eed d\u1ee5ng ch\u00fang. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y hi\u1ec7u qu\u1ea3 nh\u01b0ng c\u00f3 th\u1ec3 l\u00e0m ch\u1eadm nh\u1eb9 CPU.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Ch\u1ebf \u0111\u1ed9 \u0111\u1ee3t (Burst Mode):<\/strong> DMAC n\u1eafm to\u00e0n quy\u1ec1n ki\u1ec3m so\u00e1t bus trong su\u1ed1t qu\u00e1 tr\u00ecnh truy\u1ec1n. Ph\u01b0\u01a1ng ph\u00e1p n\u00e0y c\u1ef1c k\u1ef3 nhanh cho c\u00e1c kh\u1ed1i d\u1eef li\u1ec7u l\u1edbn nh\u01b0ng c\u00f3 th\u1ec3 khi\u1ebfn CPU ph\u1ea3i ch\u1edd (<strong>t\u00ecnh tr\u1ea1ng CPU b\u1ecb \u0111\u00ecnh tr\u1ec7<\/strong>).<\/p><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea3ng d\u01b0\u1edbi \u0111\u00e2y t\u00f3m t\u1eaft nh\u1eefng kh\u00e1c bi\u1ec7t ch\u00ednh:<\/p>\n\n\n\n<figure class=\"wp-block-table\">\n<table class=\"has-fixed-layout\">\n<colgroup><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><col style=\"min-width: 25px;\"\/><\/colgroup><tbody><tr><th colspan=\"1\" rowspan=\"1\"><p>\u0110\u1eb7c t\u00ednh<\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p>Kh\u00f4ng d\u00f9ng DMA<\/p><\/th><th colspan=\"1\" rowspan=\"1\"><p>D\u00f9ng DMA<\/p><\/th><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>M\u1ee9c \u0111\u1ed9 tham gia c\u1ee7a CPU<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Cao. CPU sao ch\u00e9p t\u1eebng byte.<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p. CPU ch\u1ec9 thi\u1ebft l\u1eadp ban \u0111\u1ea7u v\u00e0 \u0111\u01b0\u1ee3c th\u00f4ng b\u00e1o khi ho\u00e0n t\u1ea5t.<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Hi\u1ec7u qu\u1ea3<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Th\u1ea5p. CPU b\u1ecb qu\u00e1 t\u1ea3i.<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>R\u1ea5t cao. CPU v\u00e0 I\/O ho\u1ea1t \u0111\u1ed9ng song song.<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>T\u1ed1c \u0111\u1ed9 cho vi\u1ec7c truy\u1ec1n d\u1eef li\u1ec7u l\u1edbn<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Ch\u1eadm. B\u1ecb gi\u1edbi h\u1ea1n b\u1edfi b\u0103ng th\u00f4ng CPU.<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>R\u1ea5t nhanh. S\u1eed d\u1ee5ng b\u1ed9 \u0111i\u1ec1u khi\u1ec3n chuy\u00ean d\u1ee5ng.<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>\u0110\u1ed9 ph\u1ea3n h\u1ed3i c\u1ee7a h\u1ec7 th\u1ed1ng<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>C\u00f3 th\u1ec3 suy gi\u1ea3m khi t\u1ea3i I\/O cao.<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>\u0110\u01b0\u1ee3c duy tr\u00ec, v\u00ec CPU r\u1ea3nh \u0111\u1ec3 th\u1ef1c hi\u1ec7n c\u00e1c t\u00e1c v\u1ee5 quan tr\u1ecdng.<\/p><\/td><\/tr><tr><td colspan=\"1\" rowspan=\"1\"><p><strong>Ph\u00f9 h\u1ee3p nh\u1ea5t cho<\/strong><\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p>Truy\u1ec1n d\u1eef li\u1ec7u nh\u1ecf, r\u1eddi r\u1ea1c.<\/p><\/td><td colspan=\"1\" rowspan=\"1\"><p><strong>Truy\u1ec1n d\u1eef li\u1ec7u c\u00f3 th\u00f4ng l\u01b0\u1ee3ng cao<\/strong> nh\u01b0 t\u1ea3i t\u1ec7p, ch\u1ee5p video ho\u1eb7c x\u1eed l\u00fd g\u00f3i m\u1ea1ng.<\/p><\/td><\/tr><\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 V\u00ec sao DMA l\u1ea1i quan tr\u1ecdng ng\u00e0y nay? C\u00e1c \u1ee9ng d\u1ee5ng hi\u1ec7n \u0111\u1ea1i<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">DMA kh\u00f4ng ph\u1ea3i l\u00e0 c\u00f4ng ngh\u1ec7 m\u1edbi, nh\u01b0ng t\u1ea7m quan tr\u1ecdng c\u1ee7a n\u00f3 \u0111\u00e3 b\u00f9ng n\u1ed5 c\u00f9ng v\u1edbi nh\u1eefng \u0111\u00f2i h\u1ecfi c\u1ee7a \u0111i\u1ec7n to\u00e1n hi\u1ec7n \u0111\u1ea1i:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><p style=\"margin: 0px;\"><strong>\u0110i\u1ec7n to\u00e1n hi\u1ec7u n\u0103ng cao (HPC) &amp; Tr\u00ed tu\u1ec7 nh\u00e2n t\u1ea1o (AI):<\/strong> Vi\u1ec7c di chuy\u1ec3n c\u00e1c t\u1eadp d\u1eef li\u1ec7u hu\u1ea5n luy\u1ec7n kh\u1ed5ng l\u1ed3 gi\u1eefa b\u1ed9 l\u01b0u tr\u1eef, b\u1ed9 nh\u1edb GPU v\u00e0 b\u1ed9 nh\u1edb h\u1ec7 th\u1ed1ng ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c <strong>ph\u00e9p truy\u1ec1n DMA qua PCIe<\/strong>.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Trung t\u00e2m d\u1eef li\u1ec7u &amp; M\u1ea1ng:<\/strong> C\u00e1c \u1ed5 SSD <strong>NVMe t\u1ed1c \u0111\u1ed9 cao<\/strong> and <strong>v\u00e0 card m\u1ea1ng Ethernet<\/strong> 100\/400 Gigabit s\u1eed d\u1ee5ng DMA \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c t\u1ed1c \u0111\u1ed9 danh \u0111\u1ecbnh, \u0111\u1ea3m b\u1ea3o \u0111\u1ed9 tr\u1ec5 th\u1ea5p v\u00e0 th\u00f4ng l\u01b0\u1ee3ng cao. C\u00e1c c\u00f4ng ngh\u1ec7 nh\u01b0 <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/remote-direct-memory-access-rdma-data-transfer-speed-latency\/\"><strong>RDMA (Truy c\u1eadp b\u1ed9 nh\u1edb tr\u1ef1c ti\u1ebfp t\u1eeb xa)<\/strong><\/a> \u0111\u01b0a \u0111i\u1ec1u n\u00e0y l\u00ean m\u1ed9t b\u01b0\u1edbc cao h\u01a1n, cho ph\u00e9p truy c\u1eadp b\u1ed9 nh\u1edb tr\u1ef1c ti\u1ebfp gi\u1eefa c\u00e1c m\u00e1y ch\u1ee7 qua m\u1ea1ng.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>\u0110a ph\u01b0\u01a1ng ti\u1ec7n &amp; Ch\u01a1i game:<\/strong> Vi\u1ec7c ch\u1ee5p video th\u1eddi gian th\u1ef1c, x\u1eed l\u00fd \u00e2m thanh v\u00e0 truy\u1ec1n texture l\u00ean GPU \u0111\u1ec1u ph\u1ee5 thu\u1ed9c v\u00e0o DMA \u0111\u1ec3 tr\u00e1nh hi\u1ec7n t\u01b0\u1ee3ng gi\u1eadt\/lag.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>Thi\u1ebft b\u1ecb ti\u00eau d\u00f9ng:<\/strong> Ngay c\u1ea3 \u0111i\u1ec7n tho\u1ea1i th\u00f4ng minh c\u1ee7a b\u1ea1n c\u0169ng s\u1eed d\u1ee5ng DMA cho c\u00e1c t\u00e1c v\u1ee5 nh\u01b0 l\u01b0u \u1ea3nh, t\u1ea3i \u1ee9ng d\u1ee5ng v\u00e0 truy\u1ec1n d\u1eef li\u1ec7u di \u0111\u1ed9ng.<\/p><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 DMA trong th\u1ef1c t\u1ebf: Li\u00ean k\u1ebft then ch\u1ed1t t\u1edbi c\u00e1c module quang<\/strong><\/h2>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img decoding=\"async\" width=\"1200\" height=\"712\" src=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/7275ef2f350641cd9c439251ce38ba4a.webp\" alt=\"optical transceivers\" class=\"wp-image-3338\" srcset=\"https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/7275ef2f350641cd9c439251ce38ba4a.webp 1200w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/7275ef2f350641cd9c439251ce38ba4a-300x178.webp 300w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/7275ef2f350641cd9c439251ce38ba4a-1024x608.webp 1024w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/7275ef2f350641cd9c439251ce38ba4a-768x456.webp 768w, https:\/\/resourceslp.szlogic.cn\/wp-content\/uploads\/2026\/05\/7275ef2f350641cd9c439251ce38ba4a-18x12.webp 18w\" sizes=\"(max-width: 1200px) 100vw, 1200px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110i\u1ec1u n\u00e0y d\u1eabn ch\u00fang ta \u0111\u1ebfn m\u1ed9t th\u00e0nh ph\u1ea7n then ch\u1ed1t trong c\u00e1c trung t\u00e2m d\u1eef li\u1ec7u hi\u1ec7n \u0111\u1ea1i v\u00e0 m\u1ea1ng t\u1ed1c \u0111\u1ed9 cao: c\u00e1c <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-25432-optics-transceivers-sfp-modules.htm\"><strong>m\u00f4-\u0111un b\u1ed9 thu ph\u00e1t quang<\/strong><\/a>. module quang <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/products\/470377.htm\"><strong>LINK-PP 400G QSFP-DD DR4<\/strong><\/a>, nh\u01b0 <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/fiber-optic-cable-what-it-is-and-how-it-works-explained\/\"><strong>c\u00e1p quang<\/strong><\/a> c\u00e1p quang.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">t\u1ea1i t\u1ed1c \u0111\u1ed9 \u0111\u00e1ng kinh ng\u1ea1c l\u00ean t\u1edbi 400 gigabit m\u1ed7i gi\u00e2y. <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/glossary\/what-is-nic-network-interface-card\/\"><strong>th\u1ebb giao di\u1ec7n m\u1ea1ng (NIC)<\/strong><\/a> ho\u1eb7c c\u1ed5ng chuy\u1ec3n m\u1ea1ch. \u0110\u00e2y l\u00e0 s\u1ef1 h\u1ee3p t\u00e1c li\u1ec1n m\u1ea1ch:<\/p>\n\n\n\n<ol class=\"wp-block-list\" >\n<li><p style=\"margin: 0px;\">The <strong>LI\u00caN K\u1ebeT-PP 400G<\/strong> m\u00f4-\u0111un quang nh\u1eadn lu\u1ed3ng d\u1eef li\u1ec7u quang v\u00e0 chuy\u1ec3n \u0111\u1ed5i n\u00f3 th\u00e0nh t\u00edn hi\u1ec7u \u0111i\u1ec7n.<\/p><\/li><li><p style=\"margin: 0px;\">C\u00e1c t\u00edn hi\u1ec7u \u0111i\u1ec7n n\u00e0y (gi\u1edd l\u00e0 c\u00e1c g\u00f3i d\u1eef li\u1ec7u) \u0111\u01b0\u1ee3c x\u1eed l\u00fd b\u1edfi b\u1ed9 vi x\u1eed l\u00fd chuy\u00ean d\u1ee5ng c\u1ee7a NIC.<\/p><\/li><li><p style=\"margin: 0px;\"><strong>\u0110\u00e2y l\u00e0 l\u00fac DMA t\u1ecfa s\u00e1ng.<\/strong> NIC s\u1eed d\u1ee5ng DMA \u0111\u1ec3 ngay l\u1eadp t\u1ee9c v\u00e0 hi\u1ec7u qu\u1ea3 \u0111\u1eb7t c\u00e1c g\u00f3i d\u1eef li\u1ec7u \u0111\u1ebfn tr\u1ef1c ti\u1ebfp v\u00e0o b\u1ed9 nh\u1edb ch\u00ednh (RAM) c\u1ee7a m\u00e1y ch\u1ee7. Ng\u01b0\u1ee3c l\u1ea1i, khi m\u00e1y ch\u1ee7 g\u1eedi d\u1eef li\u1ec7u, NIC s\u1eed d\u1ee5ng DMA \u0111\u1ec3 l\u1ea5y c\u00e1c g\u00f3i t\u1eeb RAM nh\u1eb1m truy\u1ec1n \u0111i qua <strong>LINK-PP<\/strong> m\u00f4-\u0111un.<\/p><\/li><li><p style=\"margin: 0px;\">To\u00e0n b\u1ed9 qu\u00e1 tr\u00ecnh n\u00e0y di\u1ec5n ra v\u1edbi m\u1ee9c t\u1ea3i CPU t\u1ed1i thi\u1ec3u, cho ph\u00e9p x\u1eed l\u00fd th\u1ef1c s\u1ef1 <strong>\u1edf t\u1ed1c \u0111\u1ed9 \u0111\u01b0\u1eddng truy\u1ec1n<\/strong> \u1edf m\u1ee9c 400G. N\u1ebfu kh\u00f4ng c\u00f3 DMA, CPU s\u1ebd b\u1ecb qu\u00e1 t\u1ea3i khi c\u1ed1 g\u1eafng x\u1eed l\u00fd t\u1eebng g\u00f3i d\u1eef li\u1ec7u ri\u00eang l\u1ebb, t\u1ea1o ra t\u1eafc ngh\u1ebdn nghi\u00eam tr\u1ecdng v\u00e0 khi\u1ebfn c\u00e1c gi\u1ea3i ph\u00e1p <strong>m\u1ea1ng quang<\/strong> t\u1ed1c \u0111\u1ed9 cao tr\u1edf n\u00ean kh\u00f4ng kh\u1ea3 thi.<\/p><\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u0110\u1ed1i v\u1edbi c\u00e1c k\u1ef9 s\u01b0 thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng y\u00eau c\u1ea7u th\u00f4ng l\u01b0\u1ee3ng t\u1ed1i \u0111a, vi\u1ec7c l\u1ef1a ch\u1ecdn c\u00e1c th\u00e0nh ph\u1ea7n c\u00f3 kh\u1ea3 n\u0103ng <strong>DMA m\u1ea1nh m\u1ebd<\/strong> l\u00e0 \u0111i\u1ec1u b\u1eaft bu\u1ed9c. Vi\u1ec7c h\u1ee3p t\u00e1c v\u1edbi m\u1ed9t nh\u00e0 cung c\u1ea5p nh\u01b0 <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.link-pp.com\/\"><strong>LINK-PP<\/strong><\/a>, ng\u01b0\u1eddi \u0111\u1ea3m b\u1ea3o r\u1eb1ng c\u00e1c <strong>m\u00f4-\u0111un quang QSFP-DD m\u1eadt \u0111\u1ed9 cao<\/strong> and <strong>OSFP<\/strong> c\u1ee7a h\u1ecd \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 t\u00edch h\u1ee3p li\u1ec1n m\u1ea1ch v\u1edbi c\u00e1c \u0111\u1ed9ng c\u01a1 DMA ti\u00ean ti\u1ebfn c\u1ee7a NIC, l\u00e0 b\u01b0\u1edbc then ch\u1ed1t trong vi\u1ec7c x\u00e2y d\u1ef1ng c\u01a1 s\u1edf h\u1ea1 t\u1ea7ng c\u00f3 \u0111\u1ed9 tr\u1ec5 th\u1ea5p v\u00e0 hi\u1ec7u n\u0103ng cao.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 K\u1ebft lu\u1eadn: Ng\u01b0\u1eddi h\u00f9ng th\u1ea7m l\u1eb7ng c\u1ee7a t\u1ed1c \u0111\u1ed9<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Truy c\u1eadp B\u1ed9 nh\u1edb Tr\u1ef1c ti\u1ebfp (DMA)<\/strong> DMA l\u00e0 m\u1ed9t tr\u1ee5 c\u1ed9t n\u1ec1n t\u1ea3ng c\u1ee7a hi\u1ec7u n\u0103ng \u0111i\u1ec7n to\u00e1n hi\u1ec7n \u0111\u1ea1i. B\u1eb1ng c\u00e1ch cho ph\u00e9p c\u00e1c th\u00e0nh ph\u1ea7n ph\u1ea7n c\u1ee9ng giao ti\u1ebfp tr\u1ef1c ti\u1ebfp v\u1edbi b\u1ed9 nh\u1edb, DMA gi\u1ea3i ph\u00f3ng CPU, gi\u1ea3m \u0111\u1ed9 tr\u1ec5 v\u00e0 khai th\u00e1c t\u1ed1i \u0111a ti\u1ec1m n\u0103ng c\u1ee7a c\u00e1c thi\u1ebft b\u1ecb t\u1ed1c \u0111\u1ed9 cao \u2014 t\u1eeb \u1ed5 \u0111\u0129a NVMe \u0111\u1ebfn <a target=\"_blank\" rel=\"\" href=\"https:\/\/www.l-p.com\/store-26045-400g-qsfp-dd-osfp-qsfp112.htm\"><strong>b\u1ed9 thu ph\u00e1t quang 400G<br><\/strong><\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Khi kh\u1ed1i l\u01b0\u1ee3ng d\u1eef li\u1ec7u v\u00e0 y\u00eau c\u1ea7u v\u1ec1 t\u1ed1c \u0111\u1ed9 ti\u1ebfp t\u1ee5c t\u0103ng kh\u00f4ng ng\u1eebng, c\u00e1c nguy\u00ean l\u00fd c\u1ee7a DMA s\u1ebd v\u1eabn gi\u1eef vai tr\u00f2 trung t\u00e2m. C\u00e1c c\u00f4ng ngh\u1ec7 th\u1ebf h\u1ec7 ti\u1ebfp theo nh\u01b0 <strong>CXL (Compute Express Link)<\/strong> v\u00e0 vi\u1ec7c \u00e1p d\u1ee5ng r\u1ed9ng r\u00e3i h\u01a1n <a target=\"_blank\" rel=\"\" href=\"https:\/\/resourceslp.szlogic.cn\/vi\/knowledge-center\/rdma-over-converged-ethernet-fast-low-latency-data-transfer\/\"><strong>RDMA qua Ethernet h\u1ed9i t\u1ee5 (RoCE)<\/strong><\/a> l\u00e0 nh\u1eefng b\u01b0\u1edbc ti\u1ebfn h\u00f3a \u0111\u01b0\u1ee3c x\u00e2y d\u1ef1ng d\u1ef1a tr\u00ean kh\u00e1i ni\u1ec7m thi\u1ebft y\u1ebfu n\u00e0y. Vi\u1ec7c hi\u1ec3u r\u00f5 DMA l\u00e0 ch\u00eca kh\u00f3a \u0111\u1ec3 hi\u1ec3u c\u00e1ch th\u1ebf gi\u1edbi k\u1ef9 thu\u1eadt s\u1ed1 c\u1ee7a ch\u00fang ta v\u1eadn chuy\u1ec3n th\u00f4ng tin v\u1edbi t\u1ed1c \u0111\u1ed9 \u0111\u00e1ng kinh ng\u1ea1c m\u00e0 ch\u00fang ta \u0111\u00e3 ph\u1ee5 thu\u1ed9c v\u00e0o.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" ><strong>\u2705 C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p (FAQ)<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" >DMA l\u00e0 vi\u1ebft t\u1eaft c\u1ee7a g\u00ec?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">DMA l\u00e0 vi\u1ebft t\u1eaft c\u1ee7a Truy c\u1eadp B\u1ed9 nh\u1edb Tr\u1ef1c ti\u1ebfp. B\u1ea1n s\u1eed d\u1ee5ng n\u00f3 khi c\u00e1c thi\u1ebft b\u1ecb chuy\u1ec3n d\u1eef li\u1ec7u th\u1eb3ng v\u00e0o b\u1ed9 nh\u1edb m\u00e0 kh\u00f4ng c\u1ea7n CPU.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >Nh\u1eefng thi\u1ebft b\u1ecb n\u00e0o trong m\u00e1y t\u00ednh c\u1ee7a b\u1ea1n s\u1eed d\u1ee5ng DMA?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">B\u1ea1n t\u00ecm th\u1ea5y DMA trong \u1ed5 \u0111\u0129a c\u1ee9ng, th\u1ebb m\u1ea1ng, th\u1ebb \u00e2m thanh v\u00e0 m\u00e1y in. C\u00e1c thi\u1ebft b\u1ecb n\u00e0y s\u1eed d\u1ee5ng DMA \u0111\u1ec3 chuy\u1ec3n d\u1eef li\u1ec7u nhanh ch\u00f3ng.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" >\u0110i\u1ec1u g\u00ec x\u1ea3y ra n\u1ebfu kh\u00f4ng s\u1eed d\u1ee5ng DMA?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">N\u1ebfu kh\u00f4ng c\u00f3 DMA, CPU c\u1ee7a b\u1ea1n ph\u1ea3i x\u1eed l\u00fd m\u1ecdi l\u1ea7n truy\u1ec1n d\u1eef li\u1ec7u. \u0110i\u1ec1u n\u00e0y l\u00e0m ch\u1eadm m\u00e1y t\u00ednh v\u00e0 khi\u1ebfn n\u00f3 k\u00e9m hi\u1ec7u qu\u1ea3 h\u01a1n.<\/p>","protected":false},"excerpt":{"rendered":"<p>Truy c\u1eadp b\u1ed9 nh\u1edb tr\u1ef1c ti\u1ebfp (DMA) cho ph\u00e9p c\u00e1c thi\u1ebft b\u1ecb ph\u1ea7n c\u1ee9ng truy\u1ec1n d\u1eef li\u1ec7u v\u00e0o ho\u1eb7c ra b\u1ed9 nh\u1edb m\u00e0 kh\u00f4ng c\u1ea7n s\u1ef1 can thi\u1ec7p c\u1ee7a CPU, t\u1eeb \u0111\u00f3 n\u00e2ng cao t\u1ed1c \u0111\u1ed9 v\u00e0 hi\u1ec7u qu\u1ea3 h\u1ec7 th\u1ed1ng.<\/p>","protected":false},"author":1,"featured_media":3336,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[27],"tags":[24,26],"class_list":["post-3339","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-glossary","tag-link-pp","tag-optics-transceivers"],"blocksy_meta":[],"acf":[],"_links":{"self":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/3339","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/comments?post=3339"}],"version-history":[{"count":2,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/3339\/revisions"}],"predecessor-version":[{"id":9146,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/posts\/3339\/revisions\/9146"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/media\/3336"}],"wp:attachment":[{"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/media?parent=3339"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/categories?post=3339"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/resourceslp.szlogic.cn\/vi\/wp-json\/wp\/v2\/tags?post=3339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}