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531c221df1
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
- Fix probing of precise_ip level for default cycles event, that
got broken recently on x86_64 when its arch code started
considering invalid requesting precise samples when not sampling
(i.e. when attr.sample_period == 0).
This also fixes another problem in s/390 where the precision
probing with sample_period == 0 returned precise_ip > 0, that
then, when setting up the real cycles event (not probing) would
return EOPNOTSUPP for precise_ip > 0 (as determined previously
by probing) and sample_period > 0.
These problems resulted in attr_precise not being set to the
highest precision available on x86.64 when no event was specified,
i.e. the canonical:
perf record ./workload
would end up using attr.precise_ip = 0. As a workaround this would
need to be done:
perf record -e cycles:P ./workload
And on s/390 it would plain not work, requiring using:
perf record -e cycles ./workload
as a workaround. (Arnaldo Carvalho de Melo)
- Fix perf build with ARCH=x86_64, when ARCH should be transformed
into ARCH=x86, just like with the main kernel Makefile and
tools/objtool's, i.e. use SRCARCH. (Jiada Wang)
- Avoid accessing uninitialized data structures when unwinding with
elfutils's libdw, making it more closely mimic libunwind's unwinder.
(Milian Wolff)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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