| 37,12 → 37,12 |
|---|
| </listitem> |
| </itemizedlist> |
| |
| <para>The most narrow sence refers to the the synchronous register |
| <para>The most narrow sense refers to the the synchronous register |
| context. It includes all the preserved registers as defined by the |
| architecture. To highlight some, the program counter and stack pointer |
| take part in the synchronous register context. These are the registers |
| that must be preserved across a procedure call and during synchronous |
| context switches.</para> |
| take part in the synchronous register context. These registers must be |
| preserved across a procedure call and during synchronous context |
| switches.</para> |
| |
| <para>The next type of the context understood by the kernel is the |
| asynchronous register context. On an interrupt, the interrupted execution |
| 255,10 → 255,10 |
|---|
| <para>Normally, for the sake of cache locality, threads are scheduled on |
| one of the processors and don't leave it. Nevertheless, a situation in |
| which one processor is heavily overloaded while others sit idle can |
| occur. HelenOS deploys special kernel threads to help to mitigate this |
| occur. HelenOS deploys special kernel threads to help mitigate this |
| problem. Each processor is associated with one load balancing thread |
| called <code>kcpulb</code> that wakes up regularily to see whether its |
| processor is underbalanced or not. If yes, the thread attempts to |
| called <code>kcpulb</code> that wakes up regularly to see whether its |
| processor is underbalanced or not. If it is, the thread attempts to |
| migrate threads from other overloaded processors to its own processor's |
| run queues. When the job is done or there is no need for load balancing, |
| the thread goes to sleep.</para> |