How is cache hit and miss rate calculated?

How to calculate the cache hit ratio. The best way to calculate a cache hit ratio is to divide the total number of cache hits by the sum of the total number of cache hits, and the number of cache misses. This value is usually presented in the percentage of the requests or hits to the applicable cache.

What is the cache miss rate?

The miss rate is similar in form: the total cache misses divided by the total number of memory requests expressed as a percentage over a time interval. Note that the miss rate also equals 100 minus the hit rate.

What is the total number of cache sets in the cache memory?

64 sets
Because the main memory is 16kB, we need a minimum of 14 bits to uniquely represent a memory address. Since each cache block is of size 4 bytes, the total number of sets in the cache is 256/4, which equals 64 sets. The incoming address to the cache is divided into bits for Offset, Index and Tag.

How is cache miss calculated?

You can also calculate a miss ratio by dividing the number of misses with the total number of content requests. For example, if you look over a period of time and find that the misses your cache experienced was11, and the total number of content requests was 48, you would divide 11 by 48 to get a miss ratio of 0.229.

How is cache hit calculated?

A cache hit ratio is calculated by dividing the number of cache hits by the total number of cache hits and misses, and it measures how effective a cache is at fulfilling requests for content.

How do you calculate cache misses?

To calculate a hit ratio, divide the number of cache hits with the sum of the number of cache hits, and the number of cache misses. For example, if you have 51 cache hits and three misses over a period of time, then that would mean you would divide 51 by 54.

What are three types of cache misses?

There are three basic types of cache misses known as the 3Cs and some other less popular cache misses.

• Compulsory misses.
• Conflict misses.
• Capacity misses.
• Coherence misses.
• Coverage misses.
• System-related misses.

How do you determine cache hit or miss in Redis?

The cache hit ratio represents the efficiency of cache usage. Mathematically, it is defined as (Total key hits)/ (Total keys hits + Total key misses). “info stats” command provides keyspace_hits & keyspace_misses metric data to further calculate cache hit ratio for a running Redis instance.

What does the cache controller do during cache miss and cache hit events?

When a cache miss occurs, the system or application proceeds to locate the data in the underlying data store, which increases the duration of the request. Typically, the system may write the data to the cache, again increasing the latency, though that latency is offset by the cache hits on other data.

How is cache set calculated?

To determine the number of bits in the SET field, we need to determine the number of sets. Each set contains 2 cache blocks (2-way associative) so a set contains 32 bytes. There are 32KB bytes in the entire cache, so there are 32KB/32B = 1K sets. Thus the set field contains 10 bits (210 = 1K).