scx_utils, scx_lavd: Use ftrace for futex tracing whenever possible. #2300
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added 2 commits
July 1, 2025 13:23
Add two utility functions -- compat::cond_kprobes_enable() and compat::cond_tracepoints_enable(), which conditionally load multiple kprobes/tracepoints in a all-or-nothing manner. If any provided symbols do not exist, these functions will fail. Signed-off-by: Changwoo Min <changwoo@igalia.com>
Since ftrace has a lower overhead than tracepoint, use ftrace for futex tracing whenever possible. If any functions for futex tracing are not available (e.g., due to function inlining), fall back to using tracepoints. Signed-off-by: Changwoo Min <changwoo@igalia.com>
arighi
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Jul 1, 2025
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arighi
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Do you have some numbers? I thought ftrace was more expensive than tracepoints, due to the ftrace handler calls...
If you have numbers and this improves performance, then LGTM.
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Tracepoint is slower since it copies the arguments to the struct. |
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Since ftrace has a lower overhead than tracepoint, use ftrace for futex tracing whenever possible. If any functions for futex tracing are not available (e.g., due to function inlining), fall back to using tracepoints.