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Tue, 23 Jul 2024 08:46:39 -0700 (PDT) Received: from [192.168.1.3] ([89.47.253.130]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-427ef3f4665sm20930845e9.0.2024.07.23.08.46.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Jul 2024 08:46:38 -0700 (PDT) Message-ID: Date: Tue, 23 Jul 2024 16:46:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] perf scripts python arm-cs-trace-disasm.py: Skip disasm if address continuity is broken To: Ganapatrao Kulkarni Cc: acme@redhat.com, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, darren@os.amperecomputing.com, scclevenger@os.amperecomputing.com, james.clark@arm.com, mike.leach@linaro.org, suzuki.poulose@arm.com, Leo Yan References: <20240719092619.274730-1-gankulkarni@os.amperecomputing.com> <7302367c-311f-4655-9a83-3c4034c50086@linaro.org> <6920de94-a9c8-47f4-840f-391d1ec85c0c@os.amperecomputing.com> <8f6f221b-4c9a-42e1-b8ce-1f492caee184@linaro.org> <0a697a54-5dd8-4351-a651-991724690db2@os.amperecomputing.com> Content-Language: en-US From: James Clark In-Reply-To: <0a697a54-5dd8-4351-a651-991724690db2@os.amperecomputing.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240723_084641_631242_59FDF1D6 X-CRM114-Status: GOOD ( 26.71 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 23/07/2024 4:26 pm, Ganapatrao Kulkarni wrote: > > > On 23-07-2024 06:40 pm, James Clark wrote: >> >> >> On 22/07/2024 11:02 am, Ganapatrao Kulkarni wrote: >>> >>> Hi James, >>> >>> On 19-07-2024 08:09 pm, James Clark wrote: >>>> >>>> >>>> On 19/07/2024 10:26 am, Ganapatrao Kulkarni wrote: >>>>> To generate the instruction tracing, script uses 2 contiguous packets >>>>> address range. If there a continuity brake due to discontiguous branch >>>>> address, it is required to reset the tracing and start tracing with >>>>> the >>>>> new set of contiguous packets. >>>>> >>>>> Adding change to identify the break and complete the remaining tracing >>>>> of current packets and restart tracing from new set of packets, if >>>>> continuity is established. >>>>> >>>> >>>> Hi Ganapatrao, >>>> >>>> Can you add a before and after example of what's changed to the >>>> commit message? It wasn't immediately obvious to me if this is >>>> adding missing output, or it was correcting the tail end of the >>>> output that was previously wrong. >>> >>> It is adding tail end of the trace as well avoiding the segfault of >>> the perf application. With out this change the perf segfaults with as >>> below log >>> >>> >>> ./perf script --script=python:./scripts/python/arm-cs-trace-disasm.py >>> -- -d objdump -k ../../vmlinux -v $* > dump >>> objdump: error: the stop address should be after the start address >>> Traceback (most recent call last): >>>    File "./scripts/python/arm-cs-trace-disasm.py", line 271, in >>> process_event >>>      print_disam(dso_fname, dso_vm_start, start_addr, stop_addr) >>>    File "./scripts/python/arm-cs-trace-disasm.py", line 105, in >>> print_disam >>>      for line in read_disam(dso_fname, dso_start, start_addr, >>> stop_addr): >>>                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >>>    File "./scripts/python/arm-cs-trace-disasm.py", line 99, in >>> read_disam >>>      disasm_output = check_output(disasm).decode('utf-8').split('\n') >>>                      ^^^^^^^^^^^^^^^^^^^^ >>>    File "/usr/lib64/python3.12/subprocess.py", line 466, in check_output >>>      return run(*popenargs, stdout=PIPE, timeout=timeout, check=True, >>>             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >>>    File "/usr/lib64/python3.12/subprocess.py", line 571, in run >>>      raise CalledProcessError(retcode, process.args, >>> subprocess.CalledProcessError: Command '['objdump', '-d', '-z', >>> '--start-address=0xffff80008125b758', >>> '--stop-address=0xffff80008125a934', '../../vmlinux']' returned >>> non-zero exit status 1. >>> Fatal Python error: handler_call_die: problem in Python trace event >>> handler >>> Python runtime state: initialized >>> >>> Current thread 0x0000ffffb05054e0 (most recent call first): >>>    >>> >>> Extension modules: perf_trace_context, systemd._journal, >>> systemd._reader, systemd.id128, report._py3report, _dbus_bindings, >>> problem._py3abrt (total: 7) >>> Aborted (core dumped) >>> >>>> >>>>> Signed-off-by: Ganapatrao Kulkarni >>>>> >>>>> --- >>>>>   tools/perf/scripts/python/arm-cs-trace-disasm.py | 10 ++++++++++ >>>>>   1 file changed, 10 insertions(+) >>>>> >>>>> diff --git a/tools/perf/scripts/python/arm-cs-trace-disasm.py >>>>> b/tools/perf/scripts/python/arm-cs-trace-disasm.py >>>>> index d973c2baed1c..ad10cee2c35e 100755 >>>>> --- a/tools/perf/scripts/python/arm-cs-trace-disasm.py >>>>> +++ b/tools/perf/scripts/python/arm-cs-trace-disasm.py >>>>> @@ -198,6 +198,10 @@ def process_event(param_dict): >>>>>           cpu_data[str(cpu) + 'addr'] = addr >>>>>           return >>>>> +    if (cpu_data.get(str(cpu) + 'ip') == None): >>>>> +        cpu_data[str(cpu) + 'ip'] = ip >>>>> + >>>> >>>> Do you need to write into the global cpu_data here? Doesn't it get >>>> overwritten after you load it back into 'prev_ip' >>> >>> No, the logic is same as holding the addr of previous packet. >>> Saving the previous packet saved ip in to prev_ip before overwriting >>> with the current packet. >> >> It's not exactly the same logic as holding the addr of the previous >> sample. For addr, we return on the first None, with your change we now >> "pretend" that the second one is also the previous one: >> >>    if (cpu_data.get(str(cpu) + 'addr') == None): >>      cpu_data[str(cpu) + 'addr'] = addr >>      return  <----------------------------sample 0 return >> >>    if (cpu_data.get(str(cpu) + 'ip') == None): >>        cpu_data[str(cpu) + 'ip'] = ip <---- sample 1 save but no return >> >> Then for sample 1 'prev_ip' is actually now the 'current' IP: > > Yes, it is dummy for first packet. Added anticipating that we wont hit > the discontinuity for the first packet itself. > > Can this be changed to more intuitive like below? > > diff --git a/tools/perf/scripts/python/arm-cs-trace-disasm.py > b/tools/perf/scripts/python/arm-cs-trace-disasm.py > index d973c2baed1c..d49f5090059f 100755 > --- a/tools/perf/scripts/python/arm-cs-trace-disasm.py > +++ b/tools/perf/scripts/python/arm-cs-trace-disasm.py > @@ -198,6 +198,8 @@ def process_event(param_dict): >                 cpu_data[str(cpu) + 'addr'] = addr >                 return > > +       if (cpu_data.get(str(cpu) + 'ip') != None): > +               prev_ip = cpu_data[str(cpu) + 'ip'] > >         if (options.verbose == True): >                 print("Event type: %s" % name) > @@ -243,12 +245,18 @@ def process_event(param_dict): > >         # Record for previous sample packet >         cpu_data[str(cpu) + 'addr'] = addr > +       cpu_data[str(cpu) + 'ip'] = stop_addr > >         # Handle CS_ETM_TRACE_ON packet if start_addr=0 and stop_addr=4 >         if (start_addr == 0 and stop_addr == 4): >                 print("CPU%d: CS_ETM_TRACE_ON packet is inserted" % cpu) >                 return > > +       if (stop_addr < start_addr and prev_ip != 0): > +               # Continuity of the Packets broken, set start_addr to > previous > +               # packet ip to complete the remaining tracing of the > address range. > +               start_addr = prev_ip > + >         if (start_addr < int(dso_start) or start_addr > int(dso_end)): >                 print("Start address 0x%x is out of range [ 0x%x .. > 0x%x ] for dso %s" % (start_addr, int(dso_start), int(dso_end), dso)) >                 return > > Without this patch below is the failure log(with segfault) for reference. > > [root@sut01sys-r214 perf]# timeout 4s ./perf record -e cs_etm// -C 1 dd > if=/dev/zero of=/dev/null > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 1.087 MB perf.data ] > [root@sut01sys-r214 perf]# ./perf script > --script=python:./scripts/python/arm-cs-trace-disasm.py -- -d objdump -k > ../../vmlinux -v $* > dump > objdump: error: the stop address should be after the start address > Traceback (most recent call last): >   File "./scripts/python/arm-cs-trace-disasm.py", line 271, in > process_event >     print_disam(dso_fname, dso_vm_start, start_addr, stop_addr) >   File "./scripts/python/arm-cs-trace-disasm.py", line 105, in print_disam >     for line in read_disam(dso_fname, dso_start, start_addr, stop_addr): >                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >   File "./scripts/python/arm-cs-trace-disasm.py", line 99, in read_disam >     disasm_output = check_output(disasm).decode('utf-8').split('\n') >                     ^^^^^^^^^^^^^^^^^^^^ >   File "/usr/lib64/python3.12/subprocess.py", line 466, in check_output >     return run(*popenargs, stdout=PIPE, timeout=timeout, check=True, >            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >   File "/usr/lib64/python3.12/subprocess.py", line 571, in run >     raise CalledProcessError(retcode, process.args, > subprocess.CalledProcessError: Command '['objdump', '-d', '-z', > '--start-address=0xffff80008125b758', > '--stop-address=0xffff80008125a934', '../../vmlinux']' returned non-zero > exit status 1. > Fatal Python error: handler_call_die: problem in Python trace event handler > Python runtime state: initialized > > Current thread 0x0000ffffb90d54e0 (most recent call first): >   > > Extension modules: perf_trace_context, systemd._journal, > systemd._reader, systemd.id128, report._py3report, _dbus_bindings, > problem._py3abrt (total: 7) > Aborted (core dumped) > > > dump snippet: > ============ > Event type: branches > Sample = { cpu: 0001 addr: 0xffff80008030cb00 phys_addr: > 0x0000000000000000 ip: 0xffff800080313f0c pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff800080313f04 <__perf_event_header__init_id+0x4c>: >         ffff800080313f04:       36100094        tbz     w20, #2, > ffff800080313f14 <__perf_event_header__init_id+0x5c> >         ffff800080313f08:       f941e6a0        ldr     x0, [x21, #968] >         ffff800080313f0c:       d63f0000        blr     x0 >             perf 12720/12720 [0001]      5986.372298040 > __perf_event_header__init_id+0x54 > .../coresight/linux/kernel/events/core.c  586         return > event->clock(); > Event type: branches > Sample = { cpu: 0001 addr: 0xffff8000801bb4a8 phys_addr: > 0x0000000000000000 ip: 0xffff80008030cb0c pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff80008030cb00 : >         ffff80008030cb00:       d503233f        paciasp >         ffff80008030cb04:       a9bf7bfd        stp     x29, x30, [sp, > #-16]! >         ffff80008030cb08:       910003fd        mov     x29, sp >         ffff80008030cb0c:       97faba67        bl ffff8000801bb4a8 > >             perf 12720/12720 [0001]      5986.372298040 local_clock+0xc > ...t/linux/./include/linux/sched/clock.h   64         return sched_clock(); > Event type: branches > Sample = { cpu: 0001 addr: 0xffff80008125a8a8 phys_addr: > 0x0000000000000000 ip: 0xffff8000801bb4c8 pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff8000801bb4a8 : >         ffff8000801bb4a8:       d503233f        paciasp >         ffff8000801bb4ac:       a9be7bfd        stp     x29, x30, [sp, > #-32]! >         ffff8000801bb4b0:       910003fd        mov     x29, sp >         ffff8000801bb4b4:       a90153f3        stp     x19, x20, [sp, > #16] >         ffff8000801bb4b8:       d5384113        mrs     x19, sp_el0 >         ffff8000801bb4bc:       b9401260        ldr     w0, [x19, #16] >         ffff8000801bb4c0:       11000400        add     w0, w0, #0x1 >         ffff8000801bb4c4:       b9001260        str     w0, [x19, #16] >         ffff8000801bb4c8:       94427cf8        bl ffff80008125a8a8 > >             perf 12720/12720 [0001]      5986.372298040 > sched_clock+0x20 ...sight/linux/kernel/time/sched_clock.c  105 > ns = sched_clock_noinstr(); > Event type: branches > Sample = { cpu: 0001 addr: 0xffff80008125b758 phys_addr: > 0x0000000000000000 ip: 0xffff80008125a8e4 pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff80008125a8a8 : >         ffff80008125a8a8:       d503233f        paciasp >         ffff80008125a8ac:       a9bc7bfd        stp     x29, x30, [sp, > #-64]! >         ffff80008125a8b0:       910003fd        mov     x29, sp >         ffff80008125a8b4:       a90153f3        stp     x19, x20, [sp, > #16] >         ffff80008125a8b8:       b000e354        adrp    x20, > ffff800082ec3000 >         ffff80008125a8bc:       910d0294        add     x20, x20, #0x340 >         ffff80008125a8c0:       a90363f7        stp     x23, x24, [sp, > #48] >         ffff80008125a8c4:       91002297        add     x23, x20, #0x8 >         ffff80008125a8c8:       52800518        mov     w24, #0x28 >                 // #40 >         ffff80008125a8cc:       a9025bf5        stp     x21, x22, [sp, > #32] >         ffff80008125a8d0:       b9400296        ldr     w22, [x20] >         ffff80008125a8d4:       120002d5        and     w21, w22, #0x1 >         ffff80008125a8d8:       9bb87eb5        umull   x21, w21, w24 >         ffff80008125a8dc:       8b1502f3        add     x19, x23, x21 >         ffff80008125a8e0:       f9400e60        ldr     x0, [x19, #24] >         ffff80008125a8e4:       d63f0000        blr     x0 >             perf 12720/12720 [0001]      5986.372298040 > sched_clock_noinstr+0x3c ...sight/linux/kernel/time/sched_clock.c > 93                 cyc = (rd->read_sched_clock() - rd->epoch_cyc) & > Event type: branches > Sample = { cpu: 0001 addr: 0xffff8000801bb4cc phys_addr: > 0x0000000000000000 ip: 0xffff80008125a930 pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } > > > With fix: > ========= > > Event type: branches > Sample = { cpu: 0001 addr: 0xffff80008030cb00 phys_addr: > 0x0000000000000000 ip: 0xffff800080313f0c pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff800080313f04 <__perf_event_header__init_id+0x4c>: >         ffff800080313f04:       36100094        tbz     w20, #2, > ffff800080313f14 <__perf_event_header__init_id+0x5c> >         ffff800080313f08:       f941e6a0        ldr     x0, [x21, #968] >         ffff800080313f0c:       d63f0000        blr     x0 >             perf 12720/12720 [0001]      5986.372298040 > __perf_event_header__init_id+0x54 > .../coresight/linux/kernel/events/core.c  586         return > event->clock(); > Event type: branches > Sample = { cpu: 0001 addr: 0xffff8000801bb4a8 phys_addr: > 0x0000000000000000 ip: 0xffff80008030cb0c pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff80008030cb00 : >         ffff80008030cb00:       d503233f        paciasp >         ffff80008030cb04:       a9bf7bfd        stp     x29, x30, [sp, > #-16]! >         ffff80008030cb08:       910003fd        mov     x29, sp >         ffff80008030cb0c:       97faba67        bl ffff8000801bb4a8 > >             perf 12720/12720 [0001]      5986.372298040 local_clock+0xc > ...t/linux/./include/linux/sched/clock.h   64         return sched_clock(); > Event type: branches > Sample = { cpu: 0001 addr: 0xffff80008125a8a8 phys_addr: > 0x0000000000000000 ip: 0xffff8000801bb4c8 pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff8000801bb4a8 : >         ffff8000801bb4a8:       d503233f        paciasp >         ffff8000801bb4ac:       a9be7bfd        stp     x29, x30, [sp, > #-32]! >         ffff8000801bb4b0:       910003fd        mov     x29, sp >         ffff8000801bb4b4:       a90153f3        stp     x19, x20, [sp, > #16] >         ffff8000801bb4b8:       d5384113        mrs     x19, sp_el0 >         ffff8000801bb4bc:       b9401260        ldr     w0, [x19, #16] >         ffff8000801bb4c0:       11000400        add     w0, w0, #0x1 >         ffff8000801bb4c4:       b9001260        str     w0, [x19, #16] >         ffff8000801bb4c8:       94427cf8        bl ffff80008125a8a8 > >             perf 12720/12720 [0001]      5986.372298040 > sched_clock+0x20 ...sight/linux/kernel/time/sched_clock.c  105 > ns = sched_clock_noinstr(); > Event type: branches > Sample = { cpu: 0001 addr: 0xffff80008125b758 phys_addr: > 0x0000000000000000 ip: 0xffff80008125a8e4 pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff80008125a8a8 : >         ffff80008125a8a8:       d503233f        paciasp >         ffff80008125a8ac:       a9bc7bfd        stp     x29, x30, [sp, > #-64]! >         ffff80008125a8b0:       910003fd        mov     x29, sp >         ffff80008125a8b4:       a90153f3        stp     x19, x20, [sp, > #16] >         ffff80008125a8b8:       b000e354        adrp    x20, > ffff800082ec3000 >         ffff80008125a8bc:       910d0294        add     x20, x20, #0x340 >         ffff80008125a8c0:       a90363f7        stp     x23, x24, [sp, > #48] >         ffff80008125a8c4:       91002297        add     x23, x20, #0x8 >         ffff80008125a8c8:       52800518        mov     w24, #0x28 >                 // #40 >         ffff80008125a8cc:       a9025bf5        stp     x21, x22, [sp, > #32] >         ffff80008125a8d0:       b9400296        ldr     w22, [x20] >         ffff80008125a8d4:       120002d5        and     w21, w22, #0x1 >         ffff80008125a8d8:       9bb87eb5        umull   x21, w21, w24 >         ffff80008125a8dc:       8b1502f3        add     x19, x23, x21 >         ffff80008125a8e0:       f9400e60        ldr     x0, [x19, #24] >         ffff80008125a8e4:       d63f0000        blr     x0 It looks like the disassembly now assumes this BLR wasn't taken. We go from ffff80008125a8e4 straight through to ... >             perf 12720/12720 [0001]      5986.372298040 > sched_clock_noinstr+0x3c ...sight/linux/kernel/time/sched_clock.c > 93                 cyc = (rd->read_sched_clock() - rd->epoch_cyc) & > Event type: branches > Sample = { cpu: 0001 addr: 0xffff8000801bb4cc phys_addr: > 0x0000000000000000 ip: 0xffff80008125a930 pid: 12720 tid: 12720 period: > 1 time: 5986372298040 } >         ffff80008125a8e8 : >         ffff80008125a8e8:       f8756ae3        ldr     x3, [x23, x21] ffff80008125a8e4 which is just the previous one +4. Isn't your issue actually a decode issue in Perf itself? Why is there a discontinuity without branch samples being generated where either the source or destination address is 0? What are your record options to create this issue? As I mentioned in the previous reply I haven't been able to reproduce it.