What Are Concurrency and Threads? A Detailed Look at Basic Concepts and Application Scenarios

<p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">In modern computer systems, improving program execution efficiency and resource utilization is a key goal of development. Concurrency and threads are the core technical means to achieve this goal. As a global leader in proxy IP services, </span><a href="https://www.b2proxy.com/" target="_self"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">B2Proxy</span></a><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline"> provides high-quality proxy IP coverage in over 200 countries and regions worldwide, helping with cross-border e-commerce, ad verification, data collection, and more. Its stable network connections also support the smooth operation of concurrent tasks and multi-threaded applications.</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">What Is Concurrency?</span></h3><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Concurrency refers to a system’s ability to handle multiple tasks within the same time period. It does not require tasks to be executed </span><span style="font-size: 15px;font-style: italic;letter-spacing: 0;vertical-align: baseline">truly</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline"> “at the same time.” Instead, by switching between tasks, multiple tasks are interleaved, giving the impression of simultaneous execution.</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Features:</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Improves system response speed</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Enhances resource utilization</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Suitable for mixed I/O-intensive and CPU-intensive scenarios</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Example:</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline"> A server processes multiple users’ web requests simultaneously. Even if the CPU can only execute one thread at a time, the system can switch quickly to respond to different users.</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">What Is a Thread?</span></h3><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">A thread is the smallest unit of execution scheduling in an operating system and is part of a process. A process can contain one or more threads, which share the process’s memory resources but can execute tasks independently.</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Features:</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Threads in the same process share data and code</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">High communication efficiency between threads</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Lower creation and destruction overhead than processes</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Example:</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline"> In a browser process, multiple threads can separately handle interface rendering, network requests, and video playback.</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">Relationship Between Concurrency and Threads</span></h3><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Threads are one way to achieve concurrency</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Concurrency is a higher-level concept that can also be achieved through multi-processes or coroutines</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Multi-threading can yield better performance on multi-core CPUs</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">Difference Between Concurrency and Parallelism</span></h3><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Concurrency</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Multiple tasks alternate execution within the same time period (appears simultaneous)</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Parallelism</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Multiple tasks actually execute simultaneously at the same point in time (requires multi-core CPUs)</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Example:</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Concurrency</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: One waiter alternates between taking orders and serving dishes to multiple tables</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Parallelism</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Multiple waiters serve different tables at the same time</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">Advantages of Concurrent Programming</span></h3><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;">1.&nbsp; <span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Performance boost</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Leverage multi-core CPUs to speed up computation</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;">2.&nbsp; <span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Optimized response</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Execute other tasks during I/O wait times</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;">3.&nbsp; <span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Improved scalability</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Suitable for high-concurrency scenarios such as data collection and proxy IP scheduling</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;">4.&nbsp; <span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Better resource utilization</span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">: Reduce CPU idle time</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">Concurrency and Threads in Proxy IP Applications</span></h3><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">For scenarios like data collection and ad verification that require simultaneous access to a large number of target websites, combining proxy IPs with concurrent programming can greatly improve efficiency:</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Use multi-threading to send requests at the same time, reducing total execution time</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Apply concurrency scheduling strategies to ensure balanced use of proxy IPs and avoid single IP blocking</span></p><p style="margin: 4px 0px; font-size: 16px; font-family: 等线; line-height: 2em;"><span style="font-family: Wingdings">●<span style="font-family: &#39;Times New Roman&#39;">&nbsp;</span></span><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">Dynamically switch proxy IPs to maintain stable access under high concurrency</span></p><h3 class="paragraph text-align-type-left tco-title-heading 3" style="line-height: 2em;"><span style="font-size: 19px;letter-spacing: 0;vertical-align: baseline">FAQ</span></h3><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Q1: Does concurrency have to use multi-threading?</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">A: No. Concurrency can also be achieved with multi-processes or coroutines.</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Q2: Will multi-threading always make a program faster?</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">A: For I/O-intensive tasks, multi-threading can significantly improve speed; for purely computational tasks, the effect depends on CPU core count.</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;font-weight: bold;letter-spacing: 0;vertical-align: baseline">Q3: Which is better, concurrency or parallelism?</span></p><p style="margin: 4px 0px; font-family: 等线; font-size: 16px; line-height: 2em;"><span style="font-size: 15px;letter-spacing: 0;vertical-align: baseline">A: Neither is inherently better—it depends on the task type and hardware conditions.</span></p><p><br/></p>