调用rb_alloc分配出perf_buffer后,在ring_buffer_attach中会将rb赋值给perf_event的rb成员,分配缓冲区有两种实现方法,在编译时决定,一种是一页一页分配,这种方式会出现页之间的虚拟地址不连续,所以需要通过data_pages[]数组来记录每个页的地址,页的数量记录在rb->nr_pages中;第二种是调用vmalloc一次分配完毕,
static __always_inline int__perf_output_begin(struct perf_output_handle *handle,struct perf_sample_data *data,struct perf_event *event, unsigned int size,bool backward){struct perf_buffer *rb;unsigned long tail, offset, head;int have_lost, page_shift;struct {struct perf_event_header header;...
loop with callback to print_event b[ "open_events" ].open_perf_buffer(print_event) while true : try : b.perf_buffer_poll() except keyboardinterrupt: exit() 2.3 args 参数揭秘 对于 tracepoint_probe 中出现的 args 我们还是抱有一种好奇的心理...
#define RING_BUFFER_PAGES 16 //目前perf_event_open在glibc中没有封装,需要手工封装一下 int perf_event_open(struct perf_event_attr *attr,pid_t pid,int cpu,int group_fd,unsigned long flags) { return syscall(__NR_perf_event_open,attr,pid,cpu,group_fd,flags); } //mmap共享内存的开始地址...
可以看到,我们在用户态中触发sys_perf_event_open系统调用,内核陷入中断以后会调用perf_event_open来处理,该函数位于kernel/events/core.c文件下。perf_event_open会负责初始化计数器相关,并去获取相关的数据。这些数据会被放到ring-buffer中等待用户态来读取。 从core.c L12305开始,就是该函数相关的内容了: 代码语...
这些数据会被放到ring-buffer中等待用户态来读取。 从core.c L12305开始,就是该函数相关的内容了: /** * sys_perf_event_open - open a performance event, associate it to a task/cpu * * @attr_uptr: event_id type attributes for monitoring/sampling * @pid: target pid * @cpu: target cpu *...
perftest GPU texture/buffer performance tester VFX UnityExperiments Collection of experimental Unity Projects ShadersForFun ShadersForFun smo-shaders A collection of shaders to replicate those used in Super Mario Odyssey's Snapshot Mode. shader-graph-nodes Custom Nodes for Unity Shader Graph Minecraf...
...--- 系统调用的实现 通过软件中断实现。 **软件中断:**它是通过软件指令触发的中断。Linux系统内核响应软件中断,从用户态切换到内核态,执行相应的系统调用。.../write.txt"; int fd = -1; int i = 0; memset(buffer, '8', BUF_SIZE); fd = open(filename, O_RDWR | ...
FEATURE_PERFCOUNTERS Enable the performance counters unit NONE ENABLED NONE OPTION_PERFCOUNTERS_NUM Specify the number of performance counters to generate 0 n FEATURE_TIMER Enable the internal OpenRISC timer ENABLED ENABLED NONE FEATURE_PIC Enable the internal OpenRISC PIC ENABLED ENABLED NONE OP...
free(buffer); return -1; } #else static int unlzma(void *input, size_t input_size, void **output, size_t *output_size) { return -1; } #endif static int elf__load_sym_table(struct object *obj, Elf *e) { Elf_Scn *section = NULL; size_t shstrndx; void...