| Message ID | 20240614172631.56803-5-atrajeev@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | Add data type profiling support for powerpc | expand |
On Fri, Jun 14, 2024 at 10:56:19PM +0530, Athira Rajeev wrote: > perf annotate can be done in different ways. One way is to directly use > "perf annotate" command, other way to annotate specific symbol is to do > "perf report" and press "a" on the sample in UI mode. The approach > preferred in powerpc to parse sample for data type profiling is: > - Read directly from DSO using dso__data_read_offset > - If that fails for any case, fallback to using libcapstone > - If libcapstone is not supported, approach will use objdump > > The above works well when perf report is invoked with only sort keys for > data type ie type and typeoff. Because there is no instruction level > annotation needed if only data type information is requested for. For > annotating sample, along with type and typeoff sort key, "sym" sort key > is also needed. And by default invoking just "perf report" uses sort key > "sym" that displays the symbol information. > > With approach changes in powerpc which first reads DSO for raw > instruction, "perf annotate" and "perf report" + a key breaks since > it doesn't do the instruction level disassembly. So as I said, it'd be nice you can read the raw insn from the objdump output directly. Thanks, Namhyung > > Snippet of result from perf report: > > Samples: 1K of event 'mem-loads', 4000 Hz, Event count (approx.): 937238 > do_work /usr/bin/pmlogger [Percent: local period] > Percent│ ea230010 > │ 3a550010 > │ 3a600000 > > │ 38f60001 > │ 39490008 > │ 42400438 > 51.44 │ 81290008 > │ 7d485378 > > Here, raw instruction is displayed in the output instead of human > readable annotated form. > > One way to get the appropriate data is to specify "--objdump path", by > which code annotation will be done. But the default behaviour will be > changed. To fix this breakage, check if "sym" sort key is set. If so > fallback and use the libcapstone/objdump way of disassmbling the sample. > > With the changes and "perf report" > > Samples: 1K of event 'mem-loads', 4000 Hz, Event count (approx.): 937238 > do_work /usr/bin/pmlogger [Percent: local period] > Percent│ ld r17,16(r3) > │ addi r18,r21,16 > │ li r19,0 > > │ 8b0: rldicl r10,r10,63,33 > │ addi r10,r10,1 > │ mtctr r10 > │ ↓ b 8e4 > │ 8c0: addi r7,r22,1 > │ addi r10,r9,8 > │ ↓ bdz d00 > 51.44 │ lwz r9,8(r9) > │ mr r8,r10 > │ cmpw r20,r9 > > Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> > --- > tools/perf/util/disasm.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c > index f19496133bf0..b81cdcf4d6b4 100644 > --- a/tools/perf/util/disasm.c > +++ b/tools/perf/util/disasm.c > @@ -25,6 +25,7 @@ > #include "srcline.h" > #include "symbol.h" > #include "util.h" > +#include "sort.h" > > static regex_t file_lineno; > > @@ -1803,9 +1804,11 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args) > * not required in case of powerpc. > */ > if (arch__is(args->arch, "powerpc")) { > - err = symbol__disassemble_dso(symfs_filename, sym, args); > - if (err == 0) > - goto out_remove_tmp; > + if (sort_order && !strstr(sort_order, "sym")) { > + err = symbol__disassemble_dso(symfs_filename, sym, args); > + if (err == 0) > + goto out_remove_tmp; > + } > } > > #ifdef HAVE_LIBCAPSTONE_SUPPORT > -- > 2.43.0 >
diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c index f19496133bf0..b81cdcf4d6b4 100644 --- a/tools/perf/util/disasm.c +++ b/tools/perf/util/disasm.c @@ -25,6 +25,7 @@ #include "srcline.h" #include "symbol.h" #include "util.h" +#include "sort.h" static regex_t file_lineno; @@ -1803,9 +1804,11 @@ int symbol__disassemble(struct symbol *sym, struct annotate_args *args) * not required in case of powerpc. */ if (arch__is(args->arch, "powerpc")) { - err = symbol__disassemble_dso(symfs_filename, sym, args); - if (err == 0) - goto out_remove_tmp; + if (sort_order && !strstr(sort_order, "sym")) { + err = symbol__disassemble_dso(symfs_filename, sym, args); + if (err == 0) + goto out_remove_tmp; + } } #ifdef HAVE_LIBCAPSTONE_SUPPORT
perf annotate can be done in different ways. One way is to directly use "perf annotate" command, other way to annotate specific symbol is to do "perf report" and press "a" on the sample in UI mode. The approach preferred in powerpc to parse sample for data type profiling is: - Read directly from DSO using dso__data_read_offset - If that fails for any case, fallback to using libcapstone - If libcapstone is not supported, approach will use objdump The above works well when perf report is invoked with only sort keys for data type ie type and typeoff. Because there is no instruction level annotation needed if only data type information is requested for. For annotating sample, along with type and typeoff sort key, "sym" sort key is also needed. And by default invoking just "perf report" uses sort key "sym" that displays the symbol information. With approach changes in powerpc which first reads DSO for raw instruction, "perf annotate" and "perf report" + a key breaks since it doesn't do the instruction level disassembly. Snippet of result from perf report: Samples: 1K of event 'mem-loads', 4000 Hz, Event count (approx.): 937238 do_work /usr/bin/pmlogger [Percent: local period] Percent│ ea230010 │ 3a550010 │ 3a600000 │ 38f60001 │ 39490008 │ 42400438 51.44 │ 81290008 │ 7d485378 Here, raw instruction is displayed in the output instead of human readable annotated form. One way to get the appropriate data is to specify "--objdump path", by which code annotation will be done. But the default behaviour will be changed. To fix this breakage, check if "sym" sort key is set. If so fallback and use the libcapstone/objdump way of disassmbling the sample. With the changes and "perf report" Samples: 1K of event 'mem-loads', 4000 Hz, Event count (approx.): 937238 do_work /usr/bin/pmlogger [Percent: local period] Percent│ ld r17,16(r3) │ addi r18,r21,16 │ li r19,0 │ 8b0: rldicl r10,r10,63,33 │ addi r10,r10,1 │ mtctr r10 │ ↓ b 8e4 │ 8c0: addi r7,r22,1 │ addi r10,r9,8 │ ↓ bdz d00 51.44 │ lwz r9,8(r9) │ mr r8,r10 │ cmpw r20,r9 Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> --- tools/perf/util/disasm.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)