函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:kernel\events\core.c Create Date:2022-07-27 14:56:20
Last Modify:2022-05-20 07:50:19 Copyright©Brick
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函数名称：perf_output_read_one

函数原型：static void perf_output_read_one(struct perf_output_handle *handle, struct perf_event *event, u64 enabled, u64 running)

返回类型：void

参数：

类型参数名称
struct perf_output_handle *handle
struct perf_event *event
u64enabled
u64running
6463  read_format等于read_format
6465  n等于0
6467  values[n++]等于perf_event_count(event)
6468  如果read_format按位与PERF_FORMAT_TOTAL_TIME_ENABLED则
6469  values[n++]等于enabled加atomic64_read( & child_total_time_enabled)
6472  如果read_format按位与PERF_FORMAT_TOTAL_TIME_RUNNING则
6473  values[n++]等于running加atomic64_read( & child_total_time_running)
6476  如果read_format按位与PERF_FORMAT_ID则values[n++]等于If we inherit events we want to return the parent event id* to userspace.
6479  __output_copy(handle, values, n * sizeof(u64))
调用者
名称描述
perf_output_readXXX PERF_SAMPLE_READ vs inherited events seems difficult.* The problem is that its both hard and excessively expensive to iterate the* child list, not to mention that its impossible to IPI the children running* on another CPU, from interrupt/NMI context.