1 | |
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2 | choice |
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3 | prompt "Preemption Model" |
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4 | default PREEMPT_NONE |
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5 | |
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6 | config PREEMPT_NONE |
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7 | bool "No Forced Preemption (Server)" |
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8 | help |
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9 | This is the traditional Linux preemption model, geared towards |
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10 | throughput. It will still provide good latencies most of the |
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11 | time, but there are no guarantees and occasional longer delays |
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12 | are possible. |
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13 | |
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14 | Select this option if you are building a kernel for a server or |
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15 | scientific/computation system, or if you want to maximize the |
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16 | raw processing power of the kernel, irrespective of scheduling |
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17 | latencies. |
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18 | |
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19 | config PREEMPT_VOLUNTARY |
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20 | bool "Voluntary Kernel Preemption (Desktop)" |
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21 | help |
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22 | This option reduces the latency of the kernel by adding more |
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23 | "explicit preemption points" to the kernel code. These new |
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24 | preemption points have been selected to reduce the maximum |
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25 | latency of rescheduling, providing faster application reactions, |
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26 | at the cost of slighly lower throughput. |
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27 | |
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28 | This allows reaction to interactive events by allowing a |
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29 | low priority process to voluntarily preempt itself even if it |
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30 | is in kernel mode executing a system call. This allows |
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31 | applications to run more 'smoothly' even when the system is |
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32 | under load. |
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33 | |
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34 | Select this if you are building a kernel for a desktop system. |
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35 | |
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36 | config PREEMPT |
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37 | bool "Preemptible Kernel (Low-Latency Desktop)" |
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38 | depends on !XEN |
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39 | help |
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40 | This option reduces the latency of the kernel by making |
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41 | all kernel code (that is not executing in a critical section) |
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42 | preemptible. This allows reaction to interactive events by |
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43 | permitting a low priority process to be preempted involuntarily |
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44 | even if it is in kernel mode executing a system call and would |
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45 | otherwise not be about to reach a natural preemption point. |
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46 | This allows applications to run more 'smoothly' even when the |
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47 | system is under load, at the cost of slighly lower throughput |
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48 | and a slight runtime overhead to kernel code. |
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49 | |
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50 | Select this if you are building a kernel for a desktop or |
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51 | embedded system with latency requirements in the milliseconds |
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52 | range. |
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53 | |
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54 | endchoice |
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55 | |
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56 | config PREEMPT_BKL |
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57 | bool "Preempt The Big Kernel Lock" |
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58 | depends on SMP || PREEMPT |
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59 | default y |
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60 | help |
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61 | This option reduces the latency of the kernel by making the |
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62 | big kernel lock preemptible. |
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63 | |
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64 | Say Y here if you are building a kernel for a desktop system. |
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65 | Say N if you are unsure. |
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66 | |
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