Contents
How is cache miss measured?
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 happens if cache miss?
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.
What is read miss in cache?
A cache miss is a failed attempt to read or write a piece of data in the cache, which results in a main memory access with much longer latency. There are three kinds of cache misses: instruction read miss, data read miss, and data write miss.
How can we avoid compulsory misses?
One way of reducing the number of capacity and compulsory misses is to use prefetch tech- niques such as longer cache line sizes or prefetching methods [9, 1]. However, line sizes can not be made arbitrarily large without increasing the miss rate and greatly increasing the amount of data to be transferred.
How to get perf to report cache misses?
Edit: my CPU is an Intel i5 2300K, if that matters. On my system, an Intel Xeon X5570 @ 2.93 GHz I was able to get perf stat to report cache references and misses by requesting those events explicitly like this
What does the number of misses mean in PERF?
The number of misses indicates how often a given item of data was accessed but not present in the cache. Is this answer outdated? According to perf tutorial, Performance Monitoring Unit (PMU) events or hardware events refer to those events which can be mapped directly to CPU specific events for a CPU vendor.
What are perf cache events meaning in Stack Overflow?
According to perf tutorial, Performance Monitoring Unit (PMU) events or hardware events refer to those events which can be mapped directly to CPU specific events for a CPU vendor. But the hardware cache events refer to some hardware events monikers provided by perf, which may be mapped to actual events provided by the CPU.
How is cache use measured in Red Hat Enterprise Linux?
With Red Hat Enterprise Linux 6 and newer distributions, the system use of cache can be measured with the perf utility available from the perf RPM. perf uses the Performance Monitoring Units (PMUs) hardware in modern processors to collect data on hardware events such as cache accesses and cache misses without undue overhead on the system.