CH IV-B - Memory II

<p>To accelerate cache reading process</p> Signup and view all the answers

<p>To prevent internal fragmentation</p> Signup and view all the answers

<p>It helps avoid storage wastage</p> Signup and view all the answers

<p>Redundant data in the cache</p> Signup and view all the answers

<p>To expedite cache reading while translation occurs</p> Signup and view all the answers

<p>Increased internal fragmentation</p> Signup and view all the answers

<p>Enabling faster cache hit times</p> Signup and view all the answers

<p>48-bit</p> Signup and view all the answers

<p>Second-level</p> Signup and view all the answers

<p>First-level</p> Signup and view all the answers

<p>To speed up virtual to physical address translation</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>High Performance Architectures</p> Signup and view all the answers

<p>Computer Architecture: A Quantitative Approach</p> Signup and view all the answers

<p>36-bit</p> Signup and view all the answers

<p>Second-level</p> Signup and view all the answers

<p>Physical Memory Size × (PTE size + Virtual Address Size)</p> Signup and view all the answers

<p>To reduce address translation time</p> Signup and view all the answers

<p>Replace the least recently used block (LRU)</p> Signup and view all the answers

<p>To reduce address translation time</p> Signup and view all the answers

<p>To emphasize the high cost of write through</p> Signup and view all the answers

<p>Due to their large size</p> Signup and view all the answers

<p>The system will behave improperly and could lead to errors.</p> Signup and view all the answers

<p>To speed up virtual address to physical address translation.</p> Signup and view all the answers

<p>Valid bit and use bit.</p> Signup and view all the answers

<p>By relying on the operating system to update the TLB entries.</p> Signup and view all the answers

<p>To avoid data inconsistencies between the TLB and the page table.</p> Signup and view all the answers

<p>To avoid system malfunctions due to improper translations.</p> Signup and view all the answers

<p>2</p> Signup and view all the answers

<p>64</p> Signup and view all the answers

<p>The miss rate decreases as the number of words in a block increases.</p> Signup and view all the answers

<p>EC0 = CC + µ × ρ</p> Signup and view all the answers

<p>There is a significant improvement</p> Signup and view all the answers

<p>64 bits</p> Signup and view all the answers

<p>The number of TLB entries is increased</p> Signup and view all the answers

<p>They may store duplicate data for the same physical address</p> Signup and view all the answers

<p>To allow for cache read to begin immediately while tag comparison uses physical addresses</p> Signup and view all the answers

<p>Duplicate data may be stored in the cache</p> Signup and view all the answers

<p>Inversely proportional</p> Signup and view all the answers

<p>Larger caches</p> Signup and view all the answers

<p>Virtual memory replacement is primarily controlled by software, while cache replacement is primarily controlled by hardware</p> Signup and view all the answers

<p>2^32 bytes</p> Signup and view all the answers

<p>To act as the lower-level backing store for main memory</p> Signup and view all the answers

<p>To reduce the time required for data transfer</p> Signup and view all the answers

<p>Duplicate data in the cache</p> Signup and view all the answers

<p>To improve performance by allowing multiple memory accesses to proceed in parallel</p> Signup and view all the answers

<p>Hennessy and Patterson's book on computer architecture</p> Signup and view all the answers

<p>All levels are virtually indexed</p> Signup and view all the answers

<p>Page is fixed-size blocks, while segments are variable-size blocks</p> Signup and view all the answers

<p>Virtual memory is part of memory hierarchy</p> Signup and view all the answers

<p>The points in favor of a larger page size are: decreasing the size of the page table, allowing for larger caches with faster hit times, efficient transfer of larger pages to and from secondary storage, and reducing TLB misses by efficiently mapping more memory.</p> Signup and view all the answers

<p>The main issue is that duplicate addresses in virtual caches, such as when two programs use different virtual addresses for the same physical address, could result in two copies of the same data in the cache. This can lead to inconsistencies, incorrect values, and inefficient memory use.</p> Signup and view all the answers

<p>Using part of the page offset for cache indexing allows cache read to begin immediately while still executing the tag comparison using physical addresses. This approach combines the benefits of both virtual and physical caches, improving cache performance.</p> Signup and view all the answers

<p>By invalidating the TLB after modifying the physical page frame number or protection, the system ensures accurate translations and avoids incorrect lookups in the TLB that may have been affected by the modification.</p> Signup and view all the answers

<p>The points in favor of a smaller page size are: storage conservation by avoiding wasted space when contiguous virtual memory regions are not equal in size to a page multiple, avoiding unused memory in a page (internal fragmentation), and a faster process start-up time for smaller processes.</p> Signup and view all the answers

<p>When two programs share the same data object with virtual caches, the programs may use two different virtual addresses for the same physical address. If not handled carefully, this may result in duplicate copies of the data in the cache and inconsistencies when one copy is modified.</p> Signup and view all the answers

<p>The hierarchy level of caches in Intel Core i7 that is virtually indexed and physically tagged is the L1 data cache.</p> Signup and view all the answers

<p>The main reason in favor of using larger pages is to reduce the size of the page table. Increasing the page size results in fewer pages, which, in turn, reduces the size of the page table.</p> Signup and view all the answers

<p>Principle of locality, which states that programs tend to access similar memory locations over time, is the OS guideline that aims to minimize page faults. By taking advantage of this principle, a system can optimize memory usage and minimize the number of page faults.</p> Signup and view all the answers

<p>Computer Architecture: A Quantitative Approach.</p> Signup and view all the answers

<p>To improve the speed of virtual to physical address translation by reducing the number of memory accesses required.</p> Signup and view all the answers

<p>It reduces the complexity and latency of the cache access mechanism.</p> Signup and view all the answers

<p>To increase memory bandwidth by allowing concurrent access to multiple memory modules.</p> Signup and view all the answers

<p>It allows a program to use more memory than is physically available in the system.</p> Signup and view all the answers

<p>To provide a unique address for each physical location in memory.</p> Signup and view all the answers

<p>The virtual address space is divided into smaller chunks, which are mapped to the physical address space using a two-level TLB.</p> Signup and view all the answers

<p>To reduce memory access times by storing frequently accessed data in faster, smaller caches.</p> Signup and view all the answers

<p>It allows for a very large virtual address space, enabling programs to access a large amount of memory.</p> Signup and view all the answers

<p>By reducing memory access times and increasing memory bandwidth.</p> Signup and view all the answers

<p>To provide additional reading and learning resources for students.</p> Signup and view all the answers

<p>Memory interleaving in memory modules improves memory performance by allowing simultaneous access to multiple memory banks.</p> Signup and view all the answers

<p>A wider memory data bus increases the amount of data that can be transferred in a single clock cycle, thus improving memory bandwidth and overall performance.</p> Signup and view all the answers

<p>DRAM organization involves arranging memory cells in rows and columns for efficient access, reducing access time and enhancing memory performance.</p> Signup and view all the answers

<p>Block duplication effects improve memory performance by reducing the chances of memory conflicts and enhancing memory access speed.</p> Signup and view all the answers

<p>Interleaved memory allows for simultaneous access to multiple memory banks, reducing memory access contention and improving overall memory bandwidth.</p> Signup and view all the answers

<p>Construction technology influences factors like clock speed, latency, and data transfer rates, thereby impacting RAM performance positively.</p> Signup and view all the answers

<p>Block identification involves applying a hash function to the virtual address to create a data structure smaller than the number of virtual pages.</p> Signup and view all the answers

<p>TLB is a cache that stores recent translations of virtual memory to physical memory addresses, reducing the time for address translation.</p> Signup and view all the answers

<p>Block replacement aims to minimize page faults by using the least recently used (LRU) block identification method.</p> Signup and view all the answers

<p>Write-back caching with dirty bit is simpler and more efficient, while write-through is costly but ensures data consistency with memory.</p> Signup and view all the answers

<p>The inverted page table reduces memory overhead by creating a structure proportional to the physical pages in memory, improving efficiency.</p> Signup and view all the answers

<p>The reference bit tracks page access to implement the least recently used (LRU) block replacement policy and optimize memory usage.</p> Signup and view all the answers

<p>Due to the high miss penalty cost, a lower miss rate is preferred over simpler placing algorithms.</p> Signup and view all the answers

<p>Through paged or segmented addressing, using a data structure indexed by the page/segment number that holds the physical address of the block.</p> Signup and view all the answers

<p>It makes the OS prefer a lower miss rate over simpler placing algorithms.</p> Signup and view all the answers

<p>The page table contains the physical page address, which is concatenated with the offset to obtain the final physical address.</p> Signup and view all the answers

<p>Because the miss penalty is very high, and it involves access to slower memory devices.</p> Signup and view all the answers

<p>By allowing blocks to be placed anywhere in memory, using fully associative placement.</p> Signup and view all the answers

<p>When using interleaving of 2 banks, the system becomes 1.19 times faster, and with 4 banks, it becomes 1.39 times faster compared to the original system with simple bus.</p> Signup and view all the answers

<p>Memory interleaving improves system performance by allowing parallel access to multiple banks of memory, thereby reducing the overall latency.</p> Signup and view all the answers

<p>The advantage of quadrupling the memory bus width is that it makes the system 1.22 times faster, but the disadvantage is that it becomes prohibitively expensive and does not yield much better performance than memory interleaving with a 64-bit bus and 4 blocks.</p> Signup and view all the answers

<p>The effective cycle time considering cache and miss penalty for a block of 4 words is 3.63 using a 64-bit bus and interleaving with 4 banks.</p> Signup and view all the answers

<p>The memory interleaving technique is used to increase the memory bandwidth by allowing access to multiple memory banks simultaneously, while the bank interleaving technique is used to reduce the memory latency by distributing memory accesses across different banks.</p> Signup and view all the answers

<p>The advantages of using larger page sizes in virtual memory systems are reduced page table size, improved cache performance, reduced memory fragmentation, and improved system performance with lower overhead.</p> Signup and view all the answers

<p>The TLB ensures accurate translations after a physical page frame number change in the page table by invalidating the TLB entries that map to the old physical page frame number.</p> Signup and view all the answers

<p>DRAM is a type of RAM that stores data in capacitors and requires periodic refresh cycles to maintain the data integrity. It is commonly used in modern computers as the main memory due to its high storage capacity and low cost.</p> Signup and view all the answers

<p>The main difference between synchronous and asynchronous DRAM is that synchronous DRAM operates synchronously with the memory controller clock signal, while asynchronous DRAM operates asynchronously and requires explicit synchronization with the memory controller.</p> Signup and view all the answers

<p>DRAM latency is the time it takes to access data in the DRAM memory. Higher DRAM latency can negatively impact system performance by increasing the overall memory access time.</p> Signup and view all the answers

<p>Using part of the page offset for indexing in caches spreads out the data in the cache more evenly, which helps to mitigate the problem of cache conflicts, reducing the miss rate and improving overall cache performance.</p> Signup and view all the answers

<p>In Intel Core i7, address translation uses a two-level TLB. When a virtual address is presented, the TLB is checked for the corresponding physical address. If not found, the page table is consulted, resulting in a page table walk and a TLB miss. The faster the TLB hit ratio, the better the system performance.</p> Signup and view all the answers

<p>Virtually indexed caches use the virtual address to access the cache, while physically indexed and tagged caches use the physical address. Intel Core i7's L1 cache is virtually indexed and physically tagged, while the L2 and L3 caches are physically indexed and tagged.</p> Signup and view all the answers

<p>Memory interleaving is a technique used to improve memory performance by spreading out memory accesses across multiple memory banks. When using memory interleaving, consecutive words in memory are assigned to different banks, allowing memory access to occur concurrently and improving overall memory performance.</p> Signup and view all the answers

<p>Intel Core i7 uses a three-level cache hierarchy, with L1 being the smallest but fastest, and L3 being the largest but slowest. The benefits of using a multilevel cache hierarchy include improved cache performance and reduced memory latency by effectively managing the cache miss rate at each level.</p> Signup and view all the answers

<p>The number of words in a block, also known as block size, affects the miss rate of a cache system. Generally, increasing block size will reduce the miss rate. However, larger block sizes can lead to higher cache contention, which may negatively impact performance. The optimal block size depends on factors such as cache size, memory latency, and application characteristics.</p> Signup and view all the answers