| Age | Commit message (Collapse) | Author | Files | Lines | |
|---|---|---|---|---|---|
| 2022-04-09 | perf unwind: Don't show unwind error messages when augmenting frame pointer ↵ | James Clark | 1 | -1/+1 | |
| stack Commit Fixes: b9f6fbb3b2c29736 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'") intended to add a 'best effort' DWARF unwind that improved the frame pointer stack in most scenarios. It's expected that the unwind will fail sometimes, but this shouldn't be reported as an error. It only works when the return address can be determined from the contents of the link register alone. Fix the error shown when the unwinder requires extra registers by adding a new flag that suppresses error messages. This flag is not set in the normal --call-graph=dwarf unwind mode so that behavior is not changed. Fixes: b9f6fbb3b2c29736 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'") Reported-by: John Garry <[email protected]> Signed-off-by: James Clark <[email protected]> Tested-by: John Garry <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Alexandre Truong <[email protected]> Cc: German Gomez <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Namhyung Kim <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> | |||||
| 2022-01-14 | perf arm: Fix off-by-one directory path | Ian Rogers | 1 | -1/+1 | |
| Relative path include works in the regular build due to -I paths but may fail in other situations. Fixes: 83869019c74cc2d0 ("perf arch: Support register names from all archs") Reviewed-by: German Gomez <[email protected]> Signed-off-by: Ian Rogers <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Alexandre Truong <[email protected]> Cc: Athira Jajeev <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Clark <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> | |||||
| 2021-12-21 | perf arm64: Inject missing frames when using 'perf record --call-graph=fp' | Alexandre Truong | 1 | -0/+63 | |
| When unwinding using frame pointers on ARM64, the return address of the current function may not have been pushed into the stack when a function was interrupted, which makes perf show an incorrect call graph to the user. Consider the following example program: void leaf() { /* long computation */ } void parent() { // (1) leaf(); // (2) } ... could be compiled into (using gcc -fno-inline -fno-omit-frame-pointer): leaf: /* long computation */ nop ret parent: // (1) stp x29, x30, [sp, -16]! mov x29, sp bl parent nop ldp x29, x30, [sp], 16 // (2) ret If the program is interrupted at (1), (2), or any point in "leaf:", the call graph will skip the callers of the current function. We can unwind using the dwarf info and check if the return addr is the same as the LR register, and inject the missing frame into the call graph. Before this patch, the above example shows the following call-graph when recording using "--call-graph fp" mode in ARM64: # Children Self Command Shared Object Symbol # ........ ........ ........ ................ ...................... # 99.86% 99.86% program3 program3 [.] leaf | ---_start __libc_start_main main leaf As can be seen, the "parent" function is missing. This is specially problematic in "leaf" because for leaf functions the compiler may always omit pushing the return addr into the stack. After this patch, it shows the correct graph: # Children Self Command Shared Object Symbol # ........ ........ ........ ................ ...................... # 99.86% 99.86% program3 program3 [.] leaf | ---_start __libc_start_main main parent leaf Reviewed-by: James Clark <[email protected]> Signed-off-by: Alexandre Truong <[email protected]> Acked-by: Jiri Olsa <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: John Garry <[email protected]> Cc: Leo Yan <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Mathieu Poirier <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Will Deacon <[email protected]> Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: German Gomez <[email protected]> [ Rename machine__normalize_is() to machine__normalized_is(), as suggested by James Clark ] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> | |||||