6aa26565e6
- to isolate execution inside kernel we use a big kernel lock implemented as a spinlock - the lock is acquired asap after entering kernel mode and released as late as possible. Only one CPU as a time can execute the core kernel code - measurement son real hw show that the overhead of this lock is close to 0% of kernel time for the currnet system - the overhead of this lock may be as high as 45% of kernel time in virtual machines depending on the ratio between physical CPUs available and emulated CPUs. The performance degradation is significant
10 lines
146 B
C
10 lines
146 B
C
#include "smp.h"
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unsigned ncpus;
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unsigned ht_per_core;
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unsigned bsp_cpu_id;
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struct cpu cpus[CONFIG_MAX_CPUS];
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SPINLOCK_DEFINE(big_kernel_lock)
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