Messages in this thread | | | Subject | Re: Strange reports of perf events on powerpc 83xx | From | christophe leroy <> | Date | Wed, 2 Sep 2015 20:48:56 +0200 |
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Le 02/09/2015 16:20, Joakim Tjernlund a écrit : > On Thu, 2015-08-27 at 15:58 +0200, leroy christophe wrote: >> Hi, >> >> Has anybody already used 'perf' tool on powerpc MPC83xx ? >> >> I have been succesfully using perf on MPC8xx, but on MPC83xx I get >> something strange. >> >> perf record/report reports addresses on user stack, as if it was mixing >> up D accesses and I accesses. >> >> Any idea of what the problem can be ? > We are also experiencing strange addresses on 83xx, did find the cause > of this problem? > > We are using Linux 4.1.0 I identified this afternoon that the issue comes from perf_instruction_pointer() which reads SPRN_SIAR instead of using the NIP register from the pt_regs struct According to the MPC8323 reference manual, there is no such register.
I'm looking at the history in order to fully understand the reason. Looks like PPC_HAVE_PMU_SUPPORT is selected for all PPC_BOOK3S_32 allthought mpc832x has no PMU.
Christophe > >> # Samples: 8K of event 'cpu-clock' >> # Event count (approx.): 2196000000 >> # >> # Overhead Command Shared Object Symbol >> # ........ ............ .................. >> ............................................ >> # >> 2.62% perf_reseau4 libpthread-2.18.so [.] __libc_send >> 2.56% perf_reseau4 [kernel.kallsyms] [k] __ip_make_skb >> 1.62% perf_reseau4 [kernel.kallsyms] [k] __ip_append_data.isra.39 >> 1.55% perf_reseau4 [kernel.kallsyms] [k] ip_finish_output >> 1.33% perf_reseau4 [unknown] [k] 0x7ffffd94 >> 1.33% perf_reseau4 [unknown] [k] 0x7ffffd95 >> 1.28% perf_reseau4 [unknown] [k] 0x7ffffd97 >> 1.26% perf_reseau4 [unknown] [k] 0x7ffffda3 >> 1.24% perf_reseau4 [unknown] [k] 0x7ffffd98 >> 1.22% perf_reseau4 [unknown] [k] 0x7ffffd92 >> 1.22% perf_reseau4 [unknown] [k] 0x7ffffd9b >> 1.22% perf_reseau4 [unknown] [k] 0x7ffffdaa >> 1.21% perf_reseau4 [unknown] [k] 0x7ffffd96 >> 1.18% perf_reseau4 [unknown] [k] 0x7ffffda7 >> 1.17% perf_reseau4 [unknown] [k] 0x7ffffd8d >> 1.17% perf_reseau4 [unknown] [k] 0x7ffffd99 >> 1.13% perf_reseau4 [unknown] [k] 0x7ffffd90 >> 1.13% perf_reseau4 [unknown] [k] 0x7ffffda2 >> 1.12% perf_reseau4 [kernel.kallsyms] [k] __local_bh_enable_ip >> 1.12% perf_reseau4 [unknown] [k] 0x7ffffd9c >> 1.12% perf_reseau4 [unknown] [k] 0x7ffffd9e >> 1.10% perf_reseau4 [unknown] [k] 0x7ffffda0 >> 1.08% perf_reseau4 [unknown] [k] 0x7ffffd9f >> 1.08% perf_reseau4 [unknown] [k] 0x7ffffda6 >> 1.05% perf_reseau4 [unknown] [k] 0x7ffffda8 >> 1.02% perf_reseau4 [unknown] [k] 0x7ffffd9a >> 1.01% perf_reseau4 [unknown] [k] 0x7ffffdb0 >> 1.00% perf_reseau4 [unknown] [k] 0x7ffffd89 >> 1.00% perf_reseau4 [unknown] [k] 0x7ffffd8b >> 1.00% perf_reseau4 [unknown] [k] 0x7ffffdac
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