很多同学会利用APP,为身边的人提供帮助,解决实际的社会问题。小编身边,有同学为自己学校设计了“lost and found”(失物招领)APP,使同学们找自己丢失的东西变得更便捷;还有同学设计“时间计划表”APP,更加清楚和有效地规划自己的时间。 不过,编一个手机APP看起来是一个很难的任务,很多人打了退堂鼓。你是否也想做A...
P现在放弃CPU而不是自旋,这很好。然而,事实证明,使用此接口设计sleep和wakeup而不遭受所谓的丢失唤醒(lost wake-up)问题并非易事。假设P在第9行发现s->count==0。当P在第9行和第10行之间时,V在另一个CPU上运行:它将s->count更改为非零,并调用wakeup,这样就不会发现进程处于休眠状态,因此不会执行任何操作。
having previously served in that role at Lehigh University.Subra Suresh, former Dean of the School of Engineering, became president of Carnegie Mellon University after a stint in the Obama administration and now leads the prest...
这个过程我们可以看到很多lost wakeup。之前之所以没有出现,是因为lost wakeup需要中断已经在等待获取锁,并且uartwrite位于release和broken_sleep之间,这需要一定的巧合并不总是会发生。 如何避免Lost wakeup 现在我们的目标是消灭掉lost wakeup。这可以通过消除下面的窗口时间来实现: 首先我们必须要释放uart_tx_lock锁,因...
And as I started doing the first few classes, my results were even more surprising than that. I found I was able to learn faster using this approach than I ever had while in university. 而当我开始学前几门课程的时候,我得到的结果甚至比这个还要惊人。我发现用这种方法学习的速度比我以前在大学...
And he found this curious, and so he asked another question. How did they spend their money? And he found out that the really successful ones — actually, let’s start with the not-so-successful ones. As success increases and dollars increase, he found out that the not-so-successful one...
Projects Security Insights Additional navigation options Files riscv kernel bio.c buf.h console.c defs.h elf.h entry.S exec.c fcntl.h file.c file.h fs.c fs.h kalloc.c kernel.ld kernelvec.S log.c main.c memlayout.h param.h
“This camp must comply with regulations of the Massachusetts Department of Public Health and be licensed by the local Board of Health. Parents may request copies of background check, health care and discipline policies as well as procedures for filing grievances.” (105 CMR 430.00, 430.190 C,...
“In one of our projects, we were just making our Wi-Fi faster by maximizing throughput between nodes. Every once in a while, the system would get messed up, and we would stop getting good results. We realized that there was some person walking in the hallway, and that person’s walkin...
This multiplexing creates the illusion that each process has its own CPU, just as xv6 uses the memory allocator and hardware page tables to create the illusion that each process has its own memory. 实现xv6 Scheduling 复用机制,需要明确几个要点, ...