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linux/Documentation/userspace-api/perf_ring_buffer.rst

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Documentation: userspace-api: Document perf ring buffer mechanism In the Linux perf tool, the ring buffer serves not only as a medium for transferring PMU event data but also as a vital mechanism for hardware tracing using technologies like Intel PT and Arm CoreSight, etc. Consequently, the ring buffer mechanism plays a crucial role by ensuring high throughput for data transfer between the kernel and user space while avoiding excessive overhead caused by the ring buffer itself. This commit documents the ring buffer mechanism in detail. It explains the implementation of both the regular ring buffer and the AUX ring buffer. Additionally, it covers how these ring buffers support various tracing modes and explains the synchronization with memory barriers. Signed-off-by: Leo Yan <leo.yan@linaro.org> Reviewed-by: James Clark <james.clark@arm.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20240102085001.228815-1-leo.yan@linaro.org
2024-01-02 16:50:01 +08:00
coresight: docs: Remove target sink from examples Previously the sink had to be specified, but now it auto selects one by default. Including a sink in the examples causes issues when copy pasting the command because it might not work if that sink isn't present. Remove the sink from all the basic examples and create a new section specifically about overriding the default one. Make the text a but more concise now that it's in the advanced section, and similarly for removing the old kernel advice. Signed-off-by: James Clark <james.clark@linaro.org> Reviewed-by: Leo Yan <leo.yan@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20241210144933.295798-1-james.clark@linaro.org
2024-12-10 14:49:28 +00:00
Documentation: userspace-api: Document perf ring buffer mechanism In the Linux perf tool, the ring buffer serves not only as a medium for transferring PMU event data but also as a vital mechanism for hardware tracing using technologies like Intel PT and Arm CoreSight, etc. Consequently, the ring buffer mechanism plays a crucial role by ensuring high throughput for data transfer between the kernel and user space while avoiding excessive overhead caused by the ring buffer itself. This commit documents the ring buffer mechanism in detail. It explains the implementation of both the regular ring buffer and the AUX ring buffer. Additionally, it covers how these ring buffers support various tracing modes and explains the synchronization with memory barriers. Signed-off-by: Leo Yan <leo.yan@linaro.org> Reviewed-by: James Clark <james.clark@arm.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20240102085001.228815-1-leo.yan@linaro.org
2024-01-02 16:50:01 +08:00
coresight: docs: Remove target sink from examples Previously the sink had to be specified, but now it auto selects one by default. Including a sink in the examples causes issues when copy pasting the command because it might not work if that sink isn't present. Remove the sink from all the basic examples and create a new section specifically about overriding the default one. Make the text a but more concise now that it's in the advanced section, and similarly for removing the old kernel advice. Signed-off-by: James Clark <james.clark@linaro.org> Reviewed-by: Leo Yan <leo.yan@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20241210144933.295798-1-james.clark@linaro.org
2024-12-10 14:49:28 +00:00
Documentation: userspace-api: Document perf ring buffer mechanism In the Linux perf tool, the ring buffer serves not only as a medium for transferring PMU event data but also as a vital mechanism for hardware tracing using technologies like Intel PT and Arm CoreSight, etc. Consequently, the ring buffer mechanism plays a crucial role by ensuring high throughput for data transfer between the kernel and user space while avoiding excessive overhead caused by the ring buffer itself. This commit documents the ring buffer mechanism in detail. It explains the implementation of both the regular ring buffer and the AUX ring buffer. Additionally, it covers how these ring buffers support various tracing modes and explains the synchronization with memory barriers. Signed-off-by: Leo Yan <leo.yan@linaro.org> Reviewed-by: James Clark <james.clark@arm.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20240102085001.228815-1-leo.yan@linaro.org
2024-01-02 16:50:01 +08:00