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8f4b326d66
Function graph tracer shows negative time (wrap around) when tracing __switch_to if the nosleep-time trace option is enabled. Time compensation for nosleep-time is done by an ftrace probe on sched_switch. This doesn't work well for the following events (with letters representing timestamps): A - sched switch probe called for task T switch out B - __switch_to calltime is recorded C - sched_switch probe called for task T switch in D - __switch_to rettime is recorded If C - A > D - B, then we end up over compensating for the time spent in __switch_to giving rise to negative times in the trace output. On x86, __switch_to is not traced if function graph tracer is enabled. Do the same for arm64 as well. Cc: Todd Kjos <tkjos@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Will Deacon <will.deacon@arm.com> |
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| boot | ||
| configs | ||
| crypto | ||
| include | ||
| kernel | ||
| kvm | ||
| lib | ||
| mm | ||
| net | ||
| xen | ||
| Kconfig | ||
| Kconfig.debug | ||
| Kconfig.platforms | ||
| Makefile | ||