[PATCH V6 00/18] Add data type profiling support for powerpc
Namhyung Kim
namhyung at kernel.org
Fri Jul 12 13:48:48 AEST 2024
Hello Athira,
On Thu, Jul 11, 2024 at 8:45 PM Athira Rajeev
<atrajeev at linux.vnet.ibm.com> wrote:
>
>
>
> > On 7 Jul 2024, at 8:14 PM, Athira Rajeev <atrajeev at linux.vnet.ibm.com> wrote:
> >
> > The patchset from Namhyung added support for data type profiling
> > in perf tool. This enabled support to associate PMU samples to data
> > types they refer using DWARF debug information. With the upstream
> > perf, currently it possible to run perf report or perf annotate to
> > view the data type information on x86.
> >
> > Initial patchset posted here had changes need to enable data type
> > profiling support for powerpc.
> >
>
> Hi Namhyung,
>
> Requesting for review on this V6 patchset. I have addressed review comments from V5.
> If the patchset looks good, can you please pull this in.
It'd be nice if you can get any Acked-/Reviewed-/Tested-by tags from
powerpc folks.
Thanks,
Namhyung
> > https://lore.kernel.org/all/6e09dc28-4a2e-49d8-a2b5-ffb3396a9952@csgroup.eu/T/
> >
> > Main change were:
> > 1. powerpc instruction nmemonic table to associate load/store
> > instructions with move_ops which is use to identify if instruction
> > is a memory access one.
> > 2. To get register number and access offset from the given
> > instruction, code uses fields from "struct arch" -> objump.
> > Added entry for powerpc here.
> > 3. A get_arch_regnum to return register number from the
> > register name string.
> >
> > But the apporach used in the initial patchset used parsing of
> > disassembled code which the current perf tool implementation does.
> >
> > Example: lwz r10,0(r9)
> >
> > This line "lwz r10,0(r9)" is parsed to extract instruction name,
> > registers names and offset. Also to find whether there is a memory
> > reference in the operands, "memory_ref_char" field of objdump is used.
> > For x86, "(" is used as memory_ref_char to tackle instructions of the
> > form "mov (%rax), %rcx".
> >
> > In case of powerpc, not all instructions using "(" are the only memory
> > instructions. Example, above instruction can also be of extended form (X
> > form) "lwzx r10,0,r19". Inorder to easy identify the instruction category
> > and extract the source/target registers, second patchset added support to use
> > raw instruction. With raw instruction, macros are added to extract opcode
> > and register fields.
> > Link to second patchset:
> > https://lore.kernel.org/all/20240506121906.76639-1-atrajeev@linux.vnet.ibm.com/
> >
> > Example representation using --show-raw-insn in objdump gives result:
> >
> > 38 01 81 e8 ld r4,312(r1)
> >
> > Here "38 01 81 e8" is the raw instruction representation. In powerpc,
> > this translates to instruction form: "ld RT,DS(RA)" and binary code
> > as:
> > _____________________________________
> > | 58 | RT | RA | DS | |
> > -------------------------------------
> > 0 6 11 16 30 31
> >
> > Second patchset used "objdump" again to read the raw instruction.
> > But since there is no need to disassemble and binary code can be read
> > directly from the DSO, third patchset (ie this patchset) uses below
> > apporach. The apporach preferred in powerpc to parse sample for data
> > type profiling in V3 patchset 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
> >
> > Patchset adds support to pick the opcode and reg fields from this
> > raw/binary instruction code. This approach came in from review comment
> > by Segher Boessenkool and Christophe for the initial patchset.
> >
> > Apart from that, instruction tracking is enabled for powerpc and
> > support function is added to find variables defined as registers
> > Example, in powerpc, below two registers are
> > defined to represent variable:
> > 1. r13: represents local_paca
> > register struct paca_struct *local_paca asm("r13");
> >
> > 2. r1: represents stack_pointer
> > register void *__stack_pointer asm("r1");
> >
> > These are handled in this patchset.
> >
> > - Patch 1 is to rearrange register state type structures to header file
> > so that it can referred from other arch specific files
> > - Patch 2 is to make instruction tracking as a callback to"struct arch"
> > so that it can be implemented by other archs easily and defined in arch
> > specific files
> > - Patch 3 is to handle state type regs array size for x86 and powerpc
> > - Patch 4 adds support to capture and parse raw instruction in powerpc
> > using dso__data_read_offset utility
> > - Patch 4 also adds logic to support using objdump when doing default "perf
> > report" or "perf annotate" since it that needs disassembled instruction.
> > - Patch 5 adds disasm_line__parse to parse raw instruction for powerpc
> > - Patch 6 update parameters for reg extract functions to use raw
> > instruction on powerpc
> > - Patch 7 updates ins__find to carry raw_insn and also adds parse
> > callback for memory instructions for powerpc
> > - Patch 8 add support to identify memory instructions of opcode 31 in
> > powerpc
> > - Patch 9 adds more instructions to support instruction tracking in powerpc
> > - Patch 10 and 11 handles instruction tracking for powerpc.
> > - Patch 12, 13 and 14 add support to use libcapstone in powerpc
> > - Patch 15 and patch 16 handles support to find global register variables
> > - PAtch 17 updates data type compare functions data_type_cmp and
> > sort__typeoff_sort to include var_name along with type_name in
> > comparison.
> > - Patch 18 handles insn-stat option for perf annotate
> >
> > Note:
> > - There are remaining unknowns (25%) as seen in annotate Instruction stats
> > below.
> > - This patchset is not tested on powerpc32. In next step of enhancements
> > along with handling remaining unknowns, plan to cover powerpc32 changes
> > based on how testing goes.
> >
> > With the current patchset:
> >
> > ./perf record -a -e mem-loads sleep 1
> > ./perf report -s type,typeoff --hierarchy --group --stdio
> > ./perf annotate --data-type --insn-stat
> >
> > perf annotate logs:
> > ==================
> >
> > Annotate Instruction stats
> > total 609, ok 446 (73.2%), bad 163 (26.8%)
> >
> > Name/opcode: Good Bad
> > -----------------------------------------------------------
> > 58 : 323 80
> > 32 : 49 43
> > 34 : 33 11
> > OP_31_XOP_LDX : 8 20
> > 40 : 23 0
> > OP_31_XOP_LWARX : 5 1
> > OP_31_XOP_LWZX : 2 3
> > OP_31_XOP_LDARX : 3 0
> > 33 : 0 2
> > OP_31_XOP_LBZX : 0 1
> > OP_31_XOP_LWAX : 0 1
> > OP_31_XOP_LHZX : 0 1
> >
> > perf report logs:
> > =================
> >
> > Total Lost Samples: 0
> >
> > Samples: 1K of event 'mem-loads'
> > Event count (approx.): 937238
> >
> > Overhead Data Type Data Type Offset
> > ........ ......... ................
> > 48.60% (unknown) (unknown) +0 (no field)
> > 11.42% long unsigned int long unsigned int +0 (current_stack_pointer)
> > 4.68% struct paca_struct struct paca_struct +2312 (__current)
> > 4.57% struct paca_struct struct paca_struct +2354 (irq_soft_mask)
> > 2.69% struct paca_struct struct paca_struct +2808 (canary)
> > 2.68% struct paca_struct struct paca_struct +8 (paca_index)
> > 2.24% struct paca_struct struct paca_struct +48 (data_offset)
> > 1.43% long unsigned int long unsigned int +0 (no field)
> > 1.41% struct vm_fault struct vm_fault +0 (vma)
> > 1.29% struct task_struct struct task_struct +276 (flags)
> > 1.03% struct pt_regs struct pt_regs +264 (user_regs.msr)
> > 0.90% struct security_hook_list struct security_hook_list +0 (list.next)
> > 0.76% struct irq_desc struct irq_desc +304 (irq_data.chip)
> > 0.76% struct rq struct rq +2856 (cpu)
> > 0.72% long long unsigned int long long unsigned int +0 (no field)
> >
> > Thanks
> > Athira Rajeev
> >
> > Changelog:
> > From v5 -> v6:
> > - Addressed review comments from Namhyung
> > Conditionally define TYPE_STATE_MAX_REGS based on arch.
> > Added macro for defining width of the raw codes and spaces
> > in disasm_line__parse_powerpc.
> > Call disasm_line__parse from disasm_line__parse_powerpc
> > for generic code.
> > Renamed symbol__disassemble_dso to symbol__disassemble_raw.
> > Fixed find_data_type_global_reg to correclty free var_types
> > and change indent level.
> > Fixed data_type_cmp and sort__typeoff_sort to include var_name
> > in comparing data type entries.
>
> >
> > From v4 -> v5:
> > - Addressed review comments from Namhyung
> > Handle max number of type state regs as 16 for x86 and 32 for
> > powerpc.
> > Added generic support for objdump patch first and DSO read
> > optimisation next
> > combined patch 3 and patch 4 in patchseries V4 to one patch
> > Changed reference for "raw_insn" to use "u32"
> > Splitted "parse" callback patch changes and "ins__find" patch
> > changes into two
> > Instead of making weak function, added get_powerpc_regs to
> > extract register and offset fields for powerpc
> > - Addressed complation fail when "dwarf.h" is not present ie
> > elfutils devel is not present. Used includes for #ifdef HAVE_DWARF_SUPPORT
> > when including functions that use Dwarf references. Also
> > conditionally include some of the header files.
> >
> > From v3->v4:
> > - Addressed review comments from Ian by using capston_init from
> > "util/print_insn.c" instead of "open_capston_handle".
> > - Addressed review comment from Namhyung by moving "opcode"
> > field from "struct ins" to "struct disasm_line"
> >
> > From v2->v3:
> > - Addressed review comments from Christophe and Namhyung for V2
> > - Changed the apporach in powerpc to parse sample for data
> > type profiling as:
> > 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
> > - Include instructions with opcode as 31 and correctly categorize
> > them as memory or arithmetic instructions.
> > - Include more instructions for instruction tracking in powerpc
> >
> > From v1->v2:
> > - Addressed suggestion from Christophe Leroy and Segher Boessenkool
> > to use the binary code (raw insn) to fetch opcode, register and
> > offset fields.
> > - Added support for instruction tracking in powerpc
> > - Find the register defined variables (r13 and r1 which points to
> > local_paca and current_stack_pointer in powerpc)
> >
> > Athira Rajeev (18):
> > tools/perf: Move the data structures related to register type to
> > header file
> > tools/perf: Add "update_insn_state" callback function to handle arch
> > specific instruction tracking
> > tools/perf: Update TYPE_STATE_MAX_REGS to include max of regs in
> > powerpc
> > tools/perf: Add disasm_line__parse to parse raw instruction for
> > powerpc
> > tools/perf: Add support to capture and parse raw instruction in
> > powerpc using dso__data_read_offset utility
> > tools/perf: Update parameters for reg extract functions to use raw
> > instruction on powerpc
> > tools/perf: Add parse function for memory instructions in powerpc
> > tools/perf: Add support to identify memory instructions of opcode 31
> > in powerpc
> > tools/perf: Add some of the arithmetic instructions to support
> > instruction tracking in powerpc
> > tools/perf: Add more instructions for instruction tracking
> > tools/perf: Update instruction tracking for powerpc
> > tools/perf: Make capstone_init non-static so that it can be used
> > during symbol disassemble
> > tools/perf: Use capstone_init and remove open_capstone_handle from
> > disasm.c
> > tools/perf: Add support to use libcapstone in powerpc
> > tools/perf: Add support to find global register variables using
> > find_data_type_global_reg
> > tools/perf: Add support for global_die to capture name of variable in
> > case of register defined variable
> > tools/perf: Update data_type_cmp and sort__typeoff_sort function to
> > include var_name in comparison
> > tools/perf: Set instruction name to be used with insn-stat when using
> > raw instruction
> >
> > tools/include/linux/string.h | 2 +
> > tools/lib/string.c | 13 +
> > tools/perf/arch/arm64/annotate/instructions.c | 3 +-
> > .../arch/loongarch/annotate/instructions.c | 6 +-
> > .../perf/arch/powerpc/annotate/instructions.c | 254 ++++++++
> > tools/perf/arch/powerpc/util/dwarf-regs.c | 53 ++
> > tools/perf/arch/s390/annotate/instructions.c | 5 +-
> > tools/perf/arch/x86/annotate/instructions.c | 377 ++++++++++++
> > tools/perf/builtin-annotate.c | 4 +-
> > tools/perf/util/annotate-data.c | 545 ++++--------------
> > tools/perf/util/annotate-data.h | 83 +++
> > tools/perf/util/annotate.c | 29 +-
> > tools/perf/util/annotate.h | 6 +-
> > tools/perf/util/disasm.c | 468 +++++++++++++--
> > tools/perf/util/disasm.h | 19 +-
> > tools/perf/util/dwarf-aux.c | 1 +
> > tools/perf/util/dwarf-aux.h | 1 +
> > tools/perf/util/include/dwarf-regs.h | 12 +
> > tools/perf/util/print_insn.c | 15 +-
> > tools/perf/util/print_insn.h | 5 +
> > tools/perf/util/sort.c | 23 +-
> > 21 files changed, 1420 insertions(+), 504 deletions(-)
> >
> > --
> > 2.43.0
> >
> >
>
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