Network Bandwidth Analysis and Synchronization Techniques

The annual growth rates have settled into the low-30 percent range.

To quantify the scarcity of WAN bandwidth between different data centers.

The tool used is iperf3.

<p>The WAN bandwidth between data centers is 15× smaller than the LAN bandwidth within a data center.</p> Signup and view all the answers

<p>Eleven different regions were analyzed.</p> Signup and view all the answers

<p>Each worker needs to see other workers’ updates to the global model.</p> Signup and view all the answers

<p>The average bandwidth is calculated.</p> Signup and view all the answers

<p>It suggests that distributed systems may face latency issues due to lower WAN bandwidth.</p> Signup and view all the answers

<p>The main advantage is to reduce communication overhead over WANs by eliminating insignificant updates while maintaining an approximately correct global model.</p> Signup and view all the answers

<p>95.2% for MF, 95.6% for TM, and 97.0% for IC are insignificant.</p> Signup and view all the answers

<p>It increases the percentages to 98.8% for MF, 96.1% for TM, and 99.3% for IC.</p> Signup and view all the answers

<p>It implies that different parameters of the model converge to their optimal values at varying rates.</p> Signup and view all the answers

<p>It allows for continuous operation and improvement of the model despite delays in receiving significant updates.</p> Signup and view all the answers

<p>Data centers are aware of significant updates after a bounded network latency and wait for these updates.</p> Signup and view all the answers

<p>Insignificant updates are changes to the model that do not significantly alter the global model state.</p> Signup and view all the answers

<p>The significance of updates is quantified using various significance thresholds.</p> Signup and view all the answers

<p>The main goal of ASP is to ensure that the global model copy in each data center is approximately correct.</p> Signup and view all the answers

<p>The three techniques are the significance filter, ASP selective barrier, and ASP mirror clock.</p> Signup and view all the answers

<p>The significance filter uses a significance function and an initial significance threshold to evaluate the updates.</p> Signup and view all the answers

<p>ASP assumes that the underlying WAN bandwidth and latency are fixed, allowing the network latency to be bounded.</p> Signup and view all the answers

<p>The ASP selective barrier ensures that significant updates' latency is no more than the network latency.</p> Signup and view all the answers

<p>The significance function returns the significance of each update, often defined as the update's magnitude relative to the current value.</p> Signup and view all the answers

<p>The mirror clock provides a guarantee that worker machines are aware of significant updates in a timely manner.</p> Signup and view all the answers

<p>An update is defined as significant if its significance is larger than the initial significance threshold set by the programmer.</p> Signup and view all the answers

<p>The ASP selective barrier blocks a local worker from reading parameters until it receives significant updates, ensuring synchronization.</p> Signup and view all the answers

<p>Regret is the difference between the objective function values, denoted as $ft(x̃t)$ and $f(x^<em>)$, where $x^</em>$ minimizes $f$.</p> Signup and view all the answers

<p>The average regret $R[X]T$ approaches 0 as $T$ approaches infinity, indicating that the algorithm is converging to the optimal solution.</p> Signup and view all the answers

<p>The significance filter determines if the accumulated update of a parameter is significant and decides whether to send a MIRROR UPDATE request.</p> Signup and view all the answers

<p>The ASP synchronization model allows for the indefinite delay of insignificant updates, focusing only on significant ones.</p> Signup and view all the answers

<p>$f_t(x̃_t)$ represents the value of the objective function based on the noisy view of the parameters at time $t$.</p> Signup and view all the answers

<p>Proving that $f_t(x̃_t)$ approaches $f(x^*)$ validates that the algorithm is effectively minimizing the objective function over time.</p> Signup and view all the answers

<p>The parameter server sends only the indexes of significant updates instead of all updates, optimizing the communication process.</p> Signup and view all the answers

<p>Speeding up algorithm convergence and minimizing communication cost on WANs.</p> Signup and view all the answers

<p>The hard significance threshold guarantees that updates ensuring ML algorithm convergence are sent to other data centers.</p> Signup and view all the answers

<p>The soft significance threshold is used to utilize underutilized WAN bandwidth to speed up convergence.</p> Signup and view all the answers

<p>Data center groups designate different hubs for communication based on their location relative to other data centers.</p> Signup and view all the answers

<p>The significance filter reduces the hard significance threshold over time.</p> Signup and view all the answers

<p>The initial threshold is provided by the ML programmer or determined by a default system setting.</p> Signup and view all the answers

<p>Gaia utilizes WAN bandwidth by tuning the soft significance threshold to take advantage of underutilized bandwidth to speed up convergence.</p> Signup and view all the answers

<p>The data center in Virginia is designated as a hub to communicate with Europe, and the data center in Oregon communicates with Asia.</p> Signup and view all the answers

<p>TM is used to discover hidden semantic structures or topics in a collection of documents by analyzing word co-occurrence.</p> Signup and view all the answers

<p>The TM solver implements collapsed Gibbs sampling to learn hidden topics and their associations with documents.</p> Signup and view all the answers

<p>The Nytimes dataset, which consists of 100M words in 300K documents, is used for the experiments.</p> Signup and view all the answers

<p>Three metrics are evaluated: execution time to convergence, cost of algorithm convergence, and effectiveness compared to baseline systems.</p> Signup and view all the answers

<p>Word co-occurrence indicates relationships between words, allowing TM to categorize them into topics effectively.</p> Signup and view all the answers

<p>A matrix of rank 500 allows for a detailed representation of the data, enabling better discovery of the underlying structure.</p> Signup and view all the answers

<p>Common applications include community detection in social networks and categorization of news articles.</p> Signup and view all the answers

<p>Gaia is compared with IterStore and GeePS, which are state-of-the-art parameter server systems deployed across multiple data centers.</p> Signup and view all the answers