Perf + Opencsd (aarch64) Off Target Trace Decoding shows "could not read first record/send request"

[James Clark]

On 11/07/2023 11:40, Suzuki K Poulose wrote:
> On 11/07/2023 10:26, Pandey, Radhey Shyam wrote:
>> Hi all,
>>
>> I am trying off Target Trace Decoding using arm-cs-trace-disasm.py but
>> it doesn’t show
>>
>> proper disassembly. There is unexpected warning "could not read first
>> record".
> 
> 
>>
>> Any pointers on what the issue could be?
>>
>> Meanwhile I am trying to do trace decoding on aarch64 target and see
>> if that helps.
>>
>> I have taken simple example mentioned in [1].
>>
>> [1]:
>> http://events17.linuxfoundation.org/sites/events/files/slides/ELC-E16.pdf <http://events17.linuxfoundation.org/sites/events/files/slides/ELC-E16.pdf>
>>
>> #include int coresight_test1(int val);
>>
>> int main(void) {
>>
>> int val; val = coresight_test1(10);
>>
>> printf("val: %d\n", val);
>>
>> return 0;
>>
>> }
>>
>> perf record -e cs_etm/@tmc_etf0/u --filter
>> 'filter0x5a8/0x5e4@/home/root/libcstest.so.1.0' --per-thread ./main
>>
>> tar czf cs_example.tgz perf.data ~/.debug
>>
>> Off Target Trace Decoding: “perf report”
>>
>> tar xf cs_example.tgz
>>
>> $ rm -rf ~/.debug // remove previous trace data
>>
>> $ cp -dpR .debug ~/ // copy the current trace data
>>
>> $ perf report --stdio
>>
>> linux-xlnx/tools/perf/perf --exec-path= <snip>/linux-xlnx/tools/perf
>> script tools/perf/scripts/python/arm-cs-trace-disasm.py -- -d
>> ${XTOOL_PATH}/aarch64-linux-gnu-objdump -v
>>
> 
> I believe the perf script doesn't work with coresight trace decoding
> as we need a two pass approach for decoding the stream for figuring out
> the parameters for the queues. James Clark can give you the exact reason.
> 
> Suzuki

No that script is still working, I just tried it on and off target and
it's all fine.

I didn't use --exec-path=, I'm not sure why that's in that linked pdf,
but it didn't cause the same issue that you see if I added it.

The "could not read first record" errors actually come from the
addr2line part of Perf rather than this script. Do you have perf
report/annotate working without the script?

Or does something like this work:

  $ echo "12345" | addr2line -e \
    ~/.debug/.build-id/b7/b30ba2c0f618615a8d32d86813718bb2fdb567/debug

  fpioconst.c:?

I also just set the path to objdump directly rather than with a
variable, but I assume XTOOL_PATH is set? Although I think it must be
because you get a different error if objdump is missing.

  -d /usr/bin/aarch64-linux-gnu-objdump

James

> 
> 
> 
> 
>> ARM CoreSight Trace Data Assembler Dump
>>
>> addr2line /home/root/libcstest.so.1.0: could not read first record
>>
>>              main   748/748   [0000]         0.000000000     
>> ffffad8c05d8                         /home/root/libcstest.so.1.0
>>
>> addr2line /home/root/libcstest.so.1.0: could not send request
>>
>>              main   748/748   [0000]         0.000000000     
>> ffffad8c05d8
>>
>> addr2line /home/root/libcstest.so.1.0: could not send request
>>
>>              main   748/748   [0000]         0.000000000     
>> ffffad8c05d8
>>
>> addr2line /home/root/libcstest.so.1.0: could not send request
>>
>>              main   748/748   [0000]         0.000000000     
>> ffffad8c05d8
>>
>> addr2line /home/root/libcstest.so.1.0: could not send request
>>
>>              main   748/748   [0000]         0.000000000     
>> ffffad8c05d8
>>
>> addr2line /home/root/libcstest.so.1.0: could not send request
>>
>>              main   748/748   [0000]         0.000000000     
>> ffffad8c05e4
>>
>> End
>>
>> tools/perf/perf report -D
>>
>> <snip>
>>
>> 0x680 [0x30]: PERF_RECORD_AUXTRACE size: 0x90  offset: 0  ref:
>> 0x2890bdbd7cad6b6f  idx: 0  tid: 748  cpu: -1
>>
>> . ... CoreSight ETMV4I Trace data: size 0x20 bytes
>>
>>          Idx:0; ID:10;   I_ASYNC : Alignment Synchronisation.
>>
>>          Idx:12; ID:10;  I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
>>
>> . ... CoreSight ETMV4I Trace data: size 0x20 bytes
>>
>>          Idx:32; ID:10;  I_ASYNC : Alignment Synchronisation.
>>
>>          Idx:44; ID:10;  I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
>>
>> . ... CoreSight ETMV4I Trace data: size 0x50 bytes
>>
>>          Idx:64; ID:10;  I_ASYNC : Alignment Synchronisation.
>>
>>          Idx:76; ID:10;  I_TRACE_INFO : Trace Info.; INFO=0x0 { CC.0 }
>>
>>          Idx:81; ID:10;  I_TRACE_ON : Trace On.
>>
>>          Idx:82; ID:10;  I_ADDR_CTXT_L_64IS0 : Address & Context,
>> Long, 64 bit, IS0.; Addr=0x0000FFFFAD8C05A8; Ctxt: AArch64,EL0, NS;
>>
>>          Idx:92; ID:10;  I_ATOM_F6 : Atom format 6.; EEEEEEN
>>
>>          Idx:93; ID:10;  I_ATOM_F1 : Atom format 1.; E
>>
>>          Idx:94; ID:10;  I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.;
>> Addr=0x0000AAAAAC9107E8;
>>
>>          Idx:104; ID:10; I_TRACE_ON : Trace On.
>>
>>          Idx:105; ID:10; I_ADDR_CTXT_L_64IS0 : Address & Context,
>> Long, 64 bit, IS0.; Addr=0x0000FFFFAD8C05E8; Ctxt: AArch64,EL0, NS;
>>
>>          Idx:116; ID:10; I_ATOM_F1 : Atom format 1.; E
>>
>>          Idx:117; ID:10; I_ADDR_L_64IS0 : Address, Long, 64 bit, IS0.;
>> Addr=0x0000FFFFAD8EB4E4;
>>
>> 0x740 at perf.data <mailto:0x740 at perf.data> [0x8]: event: 68
>>
>> .
>>
>> . ... raw event: size 8 bytes
>>
>> .  0000:  44 00 00 00 00 00 08 00                          D.......
>>
>> 0x740 [0x8]: PERF_RECORD_FINISHED_ROUND
>>
>> Aggregated stats: (excludes AUX area (e.g. instruction trace) decoded
>> / synthesized events)
>>
>> Thanks,
>>
>> Radhey
>>
> 
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