Messages in this thread | | | Subject | Re: [PATCH] perf annotate: Fix unnecessary memory allocation for s390x | From | Ravi Bangoria <> | Date | Wed, 29 Nov 2017 18:04:56 +0530 |
| |
On 11/24/2017 03:16 PM, Thomas Richter wrote: > This patch fixes a bug introduced with commit d9f8dfa9baf9 > ("perf annotate s390: Implement jump types for perf annotate"). > > Perf annotate displays annotated assembler output by reading > output of command objdump and parsing the disassembled lines. For > each shown mnemonic this function sequence is executed: > > disasm_line__new() > | > +--> disasm_line__init_ins() > | > +--> ins__find() > | > +--> arch->associate_instruction_ops() > > The s390x specific function assigned to function pointer > associate_instruction_ops refers to function > s390__associate_ins_ops(). This function checks for supported > mnemonics and assigns a NULL pointer to unsupported mnemonics. > However even the NULL pointer is added to the architecture > dependend instruction array. > > This leads to an extremely large architecture instruction array > (due to array resize logic in function arch__grow_instructions()). > Depending on the objdump output being parsed the array can end up > with several ten-thousand elements. > > This patch checks if a mnemonic is supported and only adds > supported ones into the architecture instruction array. The > array does not contain elements with NULL pointers anymore. > > Before the patch (With some debug printf output): > [root@s35lp76 perf]# time ./perf annotate --stdio > /tmp/xxxbb > > real 8m49.679s > user 7m13.008s > sys 0m1.649s > [root@s35lp76 perf]# fgrep '__ins__find sorted:1 nr_instructions:' > /tmp/xxxbb | tail -1 > __ins__find sorted:1 nr_instructions:87433 ins:0x341583c0 > [root@s35lp76 perf]# > > The number of different s390x branch/jump/call/return instructions > entered into the array is 87433. > > After the patch (With some printf debug output:) > > [root@s35lp76 perf]# time ./perf annotate --stdio > /tmp/xxxaa > > real 1m24.553s > user 0m0.587s > sys 0m1.530s > [root@s35lp76 perf]# fgrep '__ins__find sorted:1 nr_instructions:' > /tmp/xxxaa | tail -1 > __ins__find sorted:1 nr_instructions:56 ins:0x3f406570 > [root@s35lp76 perf]# > > The number of different s390x branch/jump/call/return instructions > entered into the array is 56 which is sensible.
Ack-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com> > Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> > --- > tools/perf/arch/s390/annotate/instructions.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/arch/s390/annotate/instructions.c b/tools/perf/arch/s390/annotate/instructions.c > index c9a81673e8aa..89f0b6c00e3f 100644 > --- a/tools/perf/arch/s390/annotate/instructions.c > +++ b/tools/perf/arch/s390/annotate/instructions.c > @@ -16,7 +16,8 @@ static struct ins_ops *s390__associate_ins_ops(struct arch *arch, const char *na > if (!strcmp(name, "br")) > ops = &ret_ops; > > - arch__associate_ins_ops(arch, name, ops); > + if (ops) > + arch__associate_ins_ops(arch, name, ops); > return ops; > } >
| |