On 22/08/14 09:23AM, Masahiro Yamada wrote:
> On Fri, Aug 12, 2022 at 11:36 PM Owen Rafferty <owen@xxxxxxxxxxxxxxxx> wrote:
> >
> > Remove the bash build dependency for those who otherwise do not
> > have it installed. This also provides a significant speedup:
> >
> > $ make defconfig
> > $ make yes2modconfig
> >
> > ...
> >
> > $ find . -name "*.o" | grep -v vmlinux | wc
> > 3169 3169 89615
> > $ export NM=nm
> > $ time sh -c 'find . -name "*.o" | grep -v vmlinux | xargs -n1
> > ./scripts/check-local-export'
> >
> > Without patch:
> > 0m15.90s real 0m12.17s user 0m05.28s system
> >
> > With patch:
> > dash + nawk
> > 0m02.16s real 0m02.92s user 0m00.34s system
> >
> > dash + busybox awk
> > 0m02.36s real 0m03.36s user 0m00.34s system
> >
> > dash + gawk
> > 0m02.07s real 0m03.26s user 0m00.32s system
> >
> > bash + gawk
> > 0m03.55s real 0m05.00s user 0m00.54s system
> >
> > Signed-off-by: Owen Rafferty <owen@xxxxxxxxxxxxxxxx>
>
>
>
>
> How did you get those small numbers?
>
>
> The script invokes ${NM} internally,
> so it is impossible to become faster than nm.
>
> For me, it takes 55 sec just for running nm.
>
>
>
>
> $ find . -name "*.o" | wc
> 3191 3191 90085
>
> $ time sh -c 'find . -name "*.o" | grep -v vmlinux | xargs -n1 nm >/dev/null'
> nm: ./arch/x86/entry/vdso/vdso32/note.o: no symbols
> nm: ./arch/x86/entry/vdso/vdso-note.o: no symbols
>
> real 0m55.783s
> user 0m24.887s
> sys 0m30.905s
>
I'm not exactly sure. I get compatible numbers with just nm.
$ find . -name "*.o" | grep -v vmlinux | wc
3169 3169 89615
$ time sh -c 'find . -name "*.o" | grep -v vmlinux | xargs -n1 nm'
0m02.02s real 0m01.77s user 0m00.43s system
> > ---
> >
> > Notes:
> > [v2] commit message updated
> >
> > scripts/check-local-export | 95 ++++++++++++++++++--------------------
> > 1 file changed, 46 insertions(+), 49 deletions(-)
> >
> > diff --git a/scripts/check-local-export b/scripts/check-local-export
> > index 6ccc2f467416..67eaa7cf08c0 100755
> > --- a/scripts/check-local-export
> > +++ b/scripts/check-local-export
> > @@ -1,4 +1,4 @@
> > -#!/usr/bin/env bash
> > +#!/bin/sh
> > # SPDX-License-Identifier: GPL-2.0-only
> > #
> > # Copyright (C) 2022 Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > @@ -8,19 +8,6 @@
> >
> > set -e
> >
> > -# catch errors from ${NM}
> > -set -o pipefail
> > -
> > -# Run the last element of a pipeline in the current shell.
> > -# Without this, the while-loop would be executed in a subshell, and
> > -# the changes made to 'symbol_types' and 'export_symbols' would be lost.
> > -shopt -s lastpipe
> > -
> > -declare -A symbol_types
> > -declare -a export_symbols
> > -
> > -exit_code=0
> > -
> > # If there is no symbol in the object, ${NM} (both GNU nm and llvm-nm) shows
> > # 'no symbols' diagnostic (but exits with 0). It is harmless and hidden by
> > # '2>/dev/null'. However, it suppresses real error messages as well. Add a
> > @@ -29,43 +16,53 @@ exit_code=0
> > # TODO:
> > # Use --quiet instead of 2>/dev/null when we upgrade the minimum version of
> > # binutils to 2.37, llvm to 13.0.0.
> > -# Then, the following line will be really simple:
> > -# ${NM} --quiet ${1} |
> > +# Then, the following line will be simpler:
> > +# { ${NM} --quiet ${1} || kill 0; } |
> > +
> > +{ ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; kill 0; } } |
> > +awk -v "file=${1}" '
> > +BEGIN {
> > + exit_code = 0
> > + i = 0
> > +}
> > +
> > +# Skip the line if the number of fields is less than 3.
> > +#
> > +# case 1)
> > +# For undefined symbols, the first field (value) is empty.
> > +# The outout looks like this:
> > +# " U _printk"
> > +# It is unneeded to record undefined symbols.
> > +#
> > +# case 2)
> > +# For Clang LTO, llvm-nm outputs a line with type t but empty name:
> > +# "---------------- t"
> > +!length($3) {
> > + next
> > +}
> >
> > -{ ${NM} ${1} 2>/dev/null || { echo "${0}: ${NM} failed" >&2; false; } } |
> > -while read value type name
> > -do
> > - # Skip the line if the number of fields is less than 3.
> > - #
> > - # case 1)
> > - # For undefined symbols, the first field (value) is empty.
> > - # The outout looks like this:
> > - # " U _printk"
> > - # It is unneeded to record undefined symbols.
> > - #
> > - # case 2)
> > - # For Clang LTO, llvm-nm outputs a line with type 't' but empty name:
> > - # "---------------- t"
> > - if [[ -z ${name} ]]; then
> > - continue
> > - fi
> > +# save (name, type) in the associative array
> > +{ symbol_types[$3]=$2 }
> >
> > - # save (name, type) in the associative array
> > - symbol_types[${name}]=${type}
> > +# append the exported symbol to the array
> > +($3 ~ /^__ksymtab_/) {
> > + export_symbols[i] = $3
> > + sub(/^__ksymtab_/, "", export_symbols[i])
> > + i++
> > +}
> >
> > - # append the exported symbol to the array
> > - if [[ ${name} == __ksymtab_* ]]; then
> > - export_symbols+=(${name#__ksymtab_})
> > - fi
> > -done
> > +END {
> > + for (j = 0; j < i; ++j) {
> > + name = export_symbols[j]
> > + # nm(3) says "If lowercase, the symbol is usually local"
> > + if (symbol_types[name] ~ /[a-z]/) {
> > + printf "%s: error: local symbol %s was exported\n",
> > + file, name | "cat 1>&2"
> > + exit_code = 1
> > + }
> > + }
> >
> > -for name in "${export_symbols[@]}"
> > -do
> > - # nm(3) says "If lowercase, the symbol is usually local"
> > - if [[ ${symbol_types[$name]} =~ [a-z] ]]; then
> > - echo "$@: error: local symbol '${name}' was exported" >&2
> > - exit_code=1
> > - fi
> > -done
> > + exit exit_code
> > +}'
> >
> > -exit ${exit_code}
> > +exit $?
> > --
> > 2.37.2
> >
>
>
> --
> Best Regards
> Masahiro Yamada
