TWI417721B - 衰減熱資料之方法 - Google Patents

衰減熱資料之方法 Download PDF

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TWI417721B
TWI417721B TW099140971A TW99140971A TWI417721B TW I417721 B TWI417721 B TW I417721B TW 099140971 A TW099140971 A TW 099140971A TW 99140971 A TW99140971 A TW 99140971A TW I417721 B TWI417721 B TW I417721B
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block
data
hot data
hot
cold
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TW099140971A
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TW201222247A (en
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Hung Ming Lee
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Etron Technology Inc
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Priority to CN201110020075.2A priority patent/CN102073594B/zh
Priority to US13/291,068 priority patent/US20120137107A1/en
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F12/00Accessing, addressing or allocating within memory systems or architectures
    • G06F12/02Addressing or allocation; Relocation
    • G06F12/0223User address space allocation, e.g. contiguous or non contiguous base addressing
    • G06F12/023Free address space management
    • G06F12/0238Memory management in non-volatile memory, e.g. resistive RAM or ferroelectric memory
    • G06F12/0246Memory management in non-volatile memory, e.g. resistive RAM or ferroelectric memory in block erasable memory, e.g. flash memory
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F11/00Error detection; Error correction; Monitoring
    • G06F11/30Monitoring
    • G06F11/34Recording or statistical evaluation of computer activity, e.g. of down time, of input/output operation ; Recording or statistical evaluation of user activity, e.g. usability assessment
    • G06F11/3466Performance evaluation by tracing or monitoring
    • G06F11/3471Address tracing
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F2201/00Indexing scheme relating to error detection, to error correction, and to monitoring
    • G06F2201/88Monitoring involving counting
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F2212/00Indexing scheme relating to accessing, addressing or allocation within memory systems or architectures
    • G06F2212/72Details relating to flash memory management
    • G06F2212/7205Cleaning, compaction, garbage collection, erase control

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Memory System (AREA)
  • Read Only Memory (AREA)

Description

衰減熱資料之方法 METHOD OF DECAYING HOT DATA
本發明係有關於一種熱資料衰減的方法,尤指一種基於熱資料區塊進行回饋的熱資料衰減的方法。
先前技術是根據資料位置(address)在一段時間內被存取的次數,判斷資料是否為熱資料(hot data)或是冷資料(cold data)。每一個資料位置都會有對應的計數器,計數資料位置在一段時間內被存取的次數。因此,先前技術需要大的靜態隨機存取記憶體(static random access memory,SRAM)以儲存計數器的結果,且因為每一個資料位置都會有對應的計數器,所以要花費相當多的時間處理所有的計數器。而先前計數係每隔一段預定時間(例如寫入資料5000次後)衰減所有計數器的計數,再過一段預定時間,則再衰減所有計數器的計數。因此,如果資料長時間沒被存取,則對應的計數器的計數會被衰減至熱資料的門檻之下,使得熱資料變成冷資料。但先前技術除了需要大的靜態隨機存取記憶體以及耗費時間的缺點之外,還有可能因為新的熱資料其所對應的計數器的計數還不夠大,而被衰減成冷資料。另一先前技術係用哈希(hash)的方式,亦即有些資料位置共用一個計數器,以減少計數器的數量。但因為共用計數器,所以會發生誤判冷熱資料的問題。
本發明的一實施例提供一種衰減熱資料之方法。該方法包含在一快閃記憶體中保留複數個區塊(block),其中每一區塊包含複數個儲存頁(page),每一儲存頁係用以儲存一筆熱資料(hot data);以循環(ring)且循序(sequential)的方式將複數筆熱資料寫入該複數個區塊;當每一循環結束後又欲重新在該複數個區塊開始寫入熱資料時,如果一預定衰減區塊中的儲存頁的熱資料沒有被更新,則將該儲存頁中的熱資料所對應的一邏輯區塊位置(logic block address)送至一冷/熱資料識別引擎;及該冷/熱資料識別引擎根據該邏輯區塊位置衰減該邏輯區塊位置相對應的一計數器所計數的數目。
本發明提供的一種衰減熱資料之方法,首先在快閃記憶體中保留一熱資料區塊環,然後以循環且循序的方式將複數筆熱資料寫入熱資料區塊環。當循序寫入該熱資料區塊環一輪結束後,又欲重新在該熱資料區塊環開始寫入熱資料時,如果該熱資料區塊環中的一衰減區塊中的儲存頁的熱資料沒有被更新,則將儲存頁中的熱資料所對應的邏輯區塊位置送至一冷/熱資料識別引擎。該冷/熱資料識別引擎根據該邏輯區塊位置衰減該邏輯區塊位置相對應的一計數器所計數的數目。如此,可改善全部計數器一起衰減的缺點,亦不需要花費大量時間處理所有的計數器。
請參照第1圖,第1圖係說明用以衰減熱資料之熱資料區100的示意圖。熱資料區100包含一熱資料區塊環(ring)102、一冷/熱資料識別引擎(cold/hot data identify engine)104及複數個計數器106。熱資料區塊環102係為一快閃記憶體中的複數個區塊(block),其中每一區塊包含複數個儲存頁(page),每一儲存頁係用以儲存一筆熱資料(hot data)。熱資料係以循環(cyclic)且循序(sequential)的方式寫入熱資料區塊環102。冷/熱資料識別引擎104係用以根據一邏輯區塊位置(logic block address)衰減邏輯區塊位置相對應的計數器106所計數的數目。
請參照第2圖,第2圖係本發明的一實施例說明衰減熱資料之方法之流程圖。第2圖之方法係利用第1圖的熱資料區100說明,詳細步驟如下:
步驟200:開始;
步驟202:在快閃記憶體中保留熱資料區塊環102,其中熱資料區塊環102係為一快閃記憶體中的複數個區塊,且每一區塊包含複數個儲存頁,每一儲存頁係用以儲存一筆熱資料;
步驟204:是否有熱資料寫入熱資料區塊環102;如果是,進行步驟206;如果否,跳至步驟212;
步驟206:以循環且循序的方式將複數筆熱資料寫入熱資料區塊環102,且將垃圾收集(garbage collection)區塊GC的熱資料全部收集至一冷資料(cold data)區;
步驟208:當循序寫入熱資料區塊環102一輪結束後,又欲重新在熱資料區塊環102開始寫入熱資料時,將熱資料區塊環102的衰減區塊DB中的沒有被更新的熱資料所對應的一邏輯區塊位置(logic block address,LBA)送至一冷/熱資料識別引擎104;
步驟210:冷/熱資料識別引擎104根據邏輯區塊位置衰減邏輯區塊位置相對應的計數器106所計數的數目,跳回步驟204;
步驟212:結束。
在步驟204中,如果無熱資料寫入熱資料區塊環102時,直接跳至步驟212,停止將熱資料收集至一冷資料(cold data)區。在步驟206中,為了需要記憶體的空間,所以必須將垃圾收集區塊GC的熱資料全部收集至冷資料區,其中垃圾收集區塊GC係為正在寫入熱資料的區塊(active block)的下一區塊。但本發明並不受限於垃圾收集區塊GC係為正在寫入熱資料的區塊的下一區塊,在本發明的另一實施例中,垃圾收集區塊GC係為正在寫入熱資料的區塊(active block)的下一區塊之外的任一區塊。在步驟208中,當循序寫入熱資料區塊環102一輪結束後,又欲重新在熱資料區塊環102的第一個區塊開始寫入熱資料時,如果熱資料區塊環102中的衰減區塊DB中的儲存頁的熱資料仍沒有被更新,則儲存頁中的熱資料被認定為沒有足夠熱。因為儲存頁中的熱資料被認定為沒有足夠熱,所以將熱資料所對應的一邏輯區塊位置送至一冷/熱資料識別引擎104,其中儲存頁的實體頁碼(physical page number)和儲存於儲存頁中的熱資料所對應的邏輯區塊位置不同。在步驟210中,冷/熱資料識別引擎104根據邏輯區塊位置衰減邏輯區塊位置相對應的計數器106所計數的數目,以反應儲存頁中的熱資料沒有足夠熱的情況。另外,垃圾收集區塊GC可和衰減區塊DB相同。但本發明的另一實施例,垃圾收集區塊GC和衰減區塊DB不同。
綜上所述,本發明提供的衰減熱資料之方法,首先在快閃記憶體中保留熱資料區塊環,然後以循環且循序的方式將複數筆熱資料寫入熱資料區塊環。當循序寫入熱資料區塊環一輪結束後,又欲重新在熱資料區塊環開始寫入熱資料時,如果熱資料區塊環中的衰減區塊中的儲存頁的熱資料沒有被更新,則將儲存頁中的熱資料所對應的邏輯區塊位置送至冷/熱資料識別引擎。冷/熱資料識別引擎根據邏輯區塊位置衰減邏輯區塊位置相對應的計數器所計數的數目。如此,可改善全部計數器一起衰減的缺點,亦不需要花費大量時間處理所有的計數器。
以上所述僅為本發明之較佳實施例,凡依本發明申請專利範圍所做之均等變化與修飾,皆應屬本發明之涵蓋範圍。
100...熱資料區
102...熱資料區塊環
104...冷/熱資料識別引擎
106...計數器
200-212...步驟
GC...垃圾收集區塊
DB...衰減區塊
第1圖係說明用以衰減熱資料之熱資料區的示意圖。
第2圖係本發明的一實施例說明衰減熱資料之方法之流程圖。
200-212...步驟

Claims (10)

  1. 一種衰減熱資料之方法,包含:在一快閃記憶體中保留複數個區塊(block),其中每一區塊包含複數個儲存頁(page),每一儲存頁係用以儲存一筆熱資料(hot data);以循環(cyclic)且循序(sequential)的方式將複數筆熱資料寫入該複數個區塊;當每一循環結束後又欲重新在該複數個區塊開始寫入熱資料時,如果一衰減區塊中的儲存頁的熱資料沒有被更新,則將該儲存頁中沒有被更新的熱資料所對應的一邏輯區塊位置(logic block address)送至一冷/熱資料識別引擎,其中該儲存頁中沒有被更新的熱資料被定義為一不夠熱的資料;及該冷/熱資料識別引擎根據沒有被更新的熱資料所對應的該邏輯區塊位置衰減該邏輯區塊位置相對應的一計數器所計數的數目。
  2. 如請求項1所述之方法,其中衰減該邏輯區塊位置相對應的該計數器所計數的數目係將該數目除以一預定數。
  3. 如請求項1所述之方法,其中衰減該邏輯區塊位置相對應的該計數器所計數的數目係將該數目歸零。
  4. 如請求項1所述之方法,其中每一儲存頁的實體頁碼(physical page number)和儲存於該儲存頁中的熱資料所對應的邏輯區塊位置不同。
  5. 如請求項1所述之方法,另包含:將一垃圾收集(garbage collection)區塊的熱資料全部收集至一冷資料(cold data)區。
  6. 如請求項5所述之方法,其中該垃圾收集區塊和該衰減區塊相同。
  7. 如請求項5所述之方法,其中該垃圾收集區塊和該衰減區塊不同。
  8. 如請求項5所述之方法,其中欲寫入熱資料的區塊係為一激活區塊(active block),且該垃圾收集區塊係為該激活區塊的下一區塊。
  9. 如請求項5所述之方法,其中欲寫入熱資料的區塊係為一激活區塊,且該垃圾收集區塊係為該激活區塊的下一區塊之外的任一區塊。
  10. 如請求項5所述之方法,另包含:當無熱資料寫入時,停止將熱資料收集至該冷資料區。
TW099140971A 2010-11-26 2010-11-26 衰減熱資料之方法 TWI417721B (zh)

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CN201110020075.2A CN102073594B (zh) 2010-11-26 2011-01-13 衰减热数据的方法
US13/291,068 US20120137107A1 (en) 2010-11-26 2011-11-07 Method of decaying hot data

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