文档建议反馈控制台
首页
学习
活动
专区
工具
TVP
最新优惠活动
文章/答案/技术大牛
发布
精选内容/技术社群/优惠产品,尽在小程序
立即前往
    • 您找到你想要的搜索结果了吗？
    是的
    没有找到

    Android thread Scheduling

    Android is based on Linux and uses the Linux kernel’s scheduling mechanisms for determining scheduling policies. This is also true for Java code and threads. The Linux’s time sliced scheduling policy combines static and dynamic priorities. Processes can be given an initial priority from 19 to -20 (very low to very high priority). This priority will assure that higher priority processes will get more CPU time when when needed. These level are however dynamic, low level priority tasks that do not consume their CPU time will fine their dynamic priority increased. This dynamic behaviour results is an overall better responsiveness.In terms of dynamic priorities it is ensured that lower priority processes will always have a lower dynamic priority than processes with real-time priorities.Android uses two different mechanisms when scheduling the Linux kernel to perform process level scheduling

    02

    跨时钟域信号的处理方法

    在Digital Systems Engineering一书中，亚稳态是这么定义的 When sampling a changing data signal with a clock ... the order of the events determines the outcome.The smaller the time difference between the events, the longer it takes to determine which came first.When two events occur very close together, the decision process can take longer than the time allotted,and a synchronization failure occurs. 亚稳态将导致下一级输入为未知的状态。 为了防止出现亚稳态传输到下一级就要使用同步器了。 在Digital Systems Engineering一书中，同步器是这么定义的 A synchronizer is a device that samples an asynchronous signal and outputs a version of the signal that has transitions synchronized to a local or sample clock. 最常见的就同步器就是两级同步。 在使用两级同步的时候得注意被采样信号的宽度必须大于采样时钟的周期，不然就会出现下图的问题，漏采样。

    02

    I/O scheduler tunables

    fifo_batch: This parameter controls the maximum number of requests per batch.It tunes the balance between per-request latency and aggregate throughput. When low latency is the primary concern, smaller is better (where a value of 1 yields first-come first-served behavior). Increasing fifo_batch generally improves throughput, at the cost of latency variation. The default is 16. front_merges: A request that enters the scheduler is possibly contiguous to a request that is already on the queue. Either it fits in the back of that request, or it fits at the front. Hence it’s called either a back merge candidate or a front merge candidate. Typically back merges are much more common than front merges. You can set this tunable to 0 if you know your workload will never generate front merges. Otherwise leave it at its default value 1. read_expire: In all 3 schedulers, there is some form of deadline to service each Read Request. The focus is read latencies. When a read request first enters the io scheduler, it is assigned a deadline that is the current time + the read_expire value in units of milliseconds. The default value is 500 ms. write_expire: Similar to Read_Expire, this applies only to the Write Requests. The default value is 5000 ms. writes_starved: Typically more attention is given to the Read requests over write requests. But this can’t go on forever. So after the expiry of this value, some of the pending write requests get the same priority as the Reads. Default value is 1. This tunable controls how many read batches can be processed before processing a single write batch. The higher this is set, the more preference is given to reads.

    02

    EOS错误代码及中文释义

    本文集汇总了EOS区块链常见错误代码及其含义 EOS错误代码列表如下，

    错误代码错误信息中文含义
    3000000blockchain exception区块链异常
    3

    02

    扫码

    添加站长 进交流群

    领取专属 10元无门槛券

    手把手带您无忧上云

    扫码加入开发者社群

    相关资讯

    热门标签

    更多标签

    活动推荐

      运营活动

      活动名称
      广告关闭

      腾讯云开发者

      扫码关注腾讯云开发者

      扫码关注腾讯云开发者

      领取腾讯云代金券

      热门产品

      热门推荐

      更多推荐

      Copyright © 2013 - 2024 Tencent Cloud. All Rights Reserved. 腾讯云 版权所有

      深圳市腾讯计算机系统有限公司 ICP备案/许可证号：粤B2-20090059 深公网安备号 44030502008569

      腾讯云计算（北京）有限责任公司 京ICP证150476号 | 京ICP备11018762号 | 京公网安备号11010802020287

      领券