wow latency

How can we delay your program by 1 ms, 2 Ms ...... I used the timer () function for a long time when I used vbprogramming. However, after careful analysis, we will find that the timer () function has a very low precision, and the precision can only reach a dozen milliseconds. That is to say, if your intention is to delay 1 millisecond, in fact, the latency is several dozen milliseconds. What is the evidence? How can we see it? The following simple vbp

Recently read the "Redis combat", summed up some of the optimization methods mentioned in How to reduce the Redis memory usage: Use the correct data structure key length smaller occupy memory smaller (add up) value can be processed part of the data structure in the length of the smaller, A small number of cases will be using space-saving algorithm storage, can be combined with sharding to reduce total memory usage sharding: Reduce the amount of storage that can be used on a single machine (altho

MySQL master-slave database synchronization latency problem solved recently I was conducting a MySQL master-slave database synchronization test and found some problems, among which the master-slave synchronization latency problem is one of them. the following content is some explanations found on the Internet, record it for your own learning; The master-slave synchronization of MySQL is a mature architectu

Hello everyone, welcome back to the 22nd week of Performance tuning training . Last week I talked about the baseline in SQL Server, and today we go ahead and talk about waiting and I/O latency statistics in SQL Server. When I perform a SQL Server health check, I always use these 2 dimensions to globally master the health of SQL Server.Wait statistics (wait Statistics)Every time you execute a query in SQL Server, the query waits. This looks bleak for t

timeout){Signed long early = 0;Current-> timeout = jiffies + timeout;Interruptible_sleep_on (Q );If (current-> timeout> 0 ){Early = Current-> timeout-jiffies;Current-> timeout = 0;}Return early;}3. If you do not need to wait for other events, you can directly wait for a delay.Extern inline voidSchedule_timeout(INT timeout){Current-> timeout = jiffies + timeout;Current-> state = task_interruptible;Schedule ();Current-> timeout = 0;}Set_current_state (task_interruptible );Schedule_timeout (jit_de

Interrupt latency or interruption DelayThis refers to the time period from the interruption generation to the CPU response interruption, that is, the time period from T2 to T3 in the figure. The interrupt latency is caused by the kernel disabling the interrupt response of the CPU before entering the critical section. During this period, although the external device makes the interrupt request line of the CP

MySQL master-slave replication is an important part of the MySQL high-availability architecture. It can be used to achieve load balancing, high availability and failover, and provide backup. For master-slave replication monitoring, it is not reliable to rely solely on the showslavestatus provided by MySQL itself. Pt-heartbeat is a good choice for master-slave replication latency monitoring. This article describes MySQL master-slave replication is an i

meet the needs of applications in real-time control environments. It can only be used to achieve low timing precision requirements, such as dynamic display of Bitmap. Method 2: Use the sleep () function in VC to implement latency. Its unit is ms. For example, if the latency is 2 seconds, use sleep (2000 ). The accuracy is very low, and the minimum timing accuracy is only 30 ms. The disadvantage of using th

In Android, latency functions are divided into user space and kernel space: Kernel space # Include Udelay (int n ); Mdelay (INT n )); Ndelay (INT n )); These functions will lead to an endless cycle of CPU and lead to a busy wait of CPU. Usleep (int n ); Msleep (INT n )); Nsleep (INT n )); The difference between the first group and the second group of latency functions is that the first group of

We know that there are many concepts in computers that are not easy to understand. sometimes, a good analogy can beat many explanations. The following are two wonderful metaphors I have seen. let's share them with you. The first analogy is about throughput and latency. We know that there are many concepts in computers that are not easy to understand. sometimes, a good analogy can beat many explanations. The following are two wonderful metaphors I have

How can I determine the Master/Slave latency of a MySQL database? In this paper, we introduce two judgment methods: 1. Seconds_Behind_Mastervs2.mk-heartbeat, then we will introduce these content respectively. In daily work, for MySQL master-slave replication check, on the one hand, we need to ensure that the overall structure of replication is normal, on the other hand, we need to check master-slave data How can I determine the Master/Slave

This time, we will separately investigate the time of Master/Slave latency. The master-slave latency mentioned here is not ldquo; slave database update performance cannot keep up with the master database rdquo; it is ldquo; a command slave This time, we will separately investigate the time of Master/Slave latency. The master-slave

Latency of next-generation SSD controller based on low-density Inspection Author: Stephen BatesLatency Variability In the previous blog, I talked about how the Error Correction Code (ECCS) in the enterprise-level SSD controller is being converted to Low-Density Parity Check (Low-Density Parity Check. This article also implies that this conversion will have a profound impact on the latency in the next-genera

MySQLDatabaseMaster/Slave latencyHow to judge? This article introduces two methods for judging: 1. Seconds_Behind_Master vs 2. mk-heartbeat. Next we will introduce these methods separately. In daily work, for MySQL master-slave replication check, on the one hand, we need to ensure that the overall structure of the replication is normal, on the other hand, we need to check whether the master-slave data is consistent. For the former, we can monitor whether the replication thread is working normall

First, declare that the "high concurrency" here is relative, relative to the hardware, rather than absolute high concurrency. The latter must be implemented in a distributed manner. We will not discuss it here. This article focuses on the high concurrency of a single machine. Recently, a voice communication system was developed, requiring online users and 1 K concurrent calls. The hardware is two servers, core and multi-core, 4G memory, and 1g NIC (the best hardware I have ever used, so it shoul

Reprinted from: Http://www.jianshu.com/p/6e2b68a93c88 One, mobile 300ms click DelayIn general, if the mobile browser is distributing the Click event without special processing, there will usually be a delay of around 300ms. That is, when we click on the page, the mobile browser does not respond immediately, but will wait for a few moments before the effect of clicking. In the early days of the mobile web, users ' sense of 300ms latency was not obvious

Modifying the Registry improves the slow network speed caused by Tcp latency in Windows. TCP is a link-oriented communication protocol. Each sending and receiving action of both parties must be based on the normal communication link. Therefore, TCP provides the default ACK authentication mechanism. The ACK authentication method is related to the operating system. In TCP, data validation is often delayed. When the delay timer does not overflow, general

Processing of network latency in online shooting games (Jinqing's column) Network latency in online games is unavoidable.For example, if a mobile client sends a command to receive confirmation from the server, there will be a latency of Ms,If the client is moved after ms, the operability will be very poor.Generally, it does not wait for the server to confirm. M

Tags: H.264 thread buffer parallel The latency of x264 encoding is studied. The method is to add log in x264.c Static int encode (x264_param_t * Param, cli_opt_t * OPT) { ... I _frame_size = encode_frame (H, opt-> Hout, pic, last_dts ); If (I _frame_size = 0) // delay Frames Fprintf (stderr, "output zero % d \ n", I _frame ); ... } After statistics, we found that the number of x264 encoded delayed frames conforms to the following formula. H-> frame

This is a BDP test in rhca, which is also a very common simulation of latency and packet loss. I will share it with you now. We also use the application software to test TCP/UDP comparison. When we test the impact of BDP on TCP/IP, we all need some network latency and packet loss simulation, many commercial software can do this. In fact, the perfect Linux itself can use TC to implement this function. the ne