(2) We also optimize the caching strategy which takes both the user's access result and cache hit
ratio into account.
As verified by Pfaff et al., the overall cache hit
rate of Open vSwitch was 97.7% (i.e., the value of [p.sub.1]) in a real commercial multitenant data center .
Compared with the result of  regarding the number of queries submitted by a single user to generate an obfuscation area, our cache hit
ratio was 0, indicating that, without using the cache, four users or more are required to simultaneously transmit a query to meet the privacy requirements with a reduced number of pseudoqueries sent by the anonymizer to the LBS server.
3, if there is cache hit
i.e s'" = 0 equation.3 becomes:
If a cache hit
occurs, the reference bit is set to 1.
The results we obtained for the cache hit
ratio under different cache sizes are displayed in Figures 2, 3 and 4.
An expires- based cache hit
is almost always faster than a validation-based near hit.
Although local client caches are effective, the performance of a distributed file system is often limited by the poor server cache hit
rate [Dahlin et al.
Prefetch efficiency is defined to be the ratio of useful prefetches to total prefetches where a useful prefetch occurs whenever a prefetched block results in a cache hit
. The value of K is initialized to one, incremented whenever the prefetch efficiency exceeds a predetermined upper threshold, and decremented whenever the efficiency drops below a lower threshold, as shown in Figure 7.
If a reuse results in a cache hit
we say that the reuse is realized.
Figure 11 shows the average hit rate across all client caches for the UNIFORM workload.(14) As can be seen in the figure, the avoidance-based algorithms all have higher client cache hit
rates than C2PL.
Similarly, when the data are already in the cache, it is called a cache hit
. The ratio of cache hits
to the number of attempts to access the cache is called the hit rate, which is the key to performance.