From: Christian Biesinger Date: Fri, 27 Sep 2019 18:32:07 +0000 (-0500) Subject: Use libxxhash for hashing, if present X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ccb1ba62299edce72053dd567b9d384814e11885;p=binutils-gdb.git Use libxxhash for hashing, if present XXHash is faster than htab_hash_string: ------------------------------------------------------------ Benchmark Time CPU Iterations ------------------------------------------------------------ BM_xxh3 11 ns 11 ns 65887249 BM_xxh32 19 ns 19 ns 36511877 BM_xxh64 16 ns 16 ns 42964585 BM_hash_string 182 ns 182 ns 3853125 BM_iterative_hash 77 ns 77 ns 9087638 Unfortunately, XXH3 is still experimental (see https://github.com/Cyan4973/xxHash#user-content-new-experimental-hash-algorithm) However, regular XXH64 is still a lot faster than htab_hash_string per my benchmark above. I used the following string for the benchmark: static constexpr char str[] = "_ZZZL13make_gdb_typeP7gdbarchP10tdesc_typeEN16gdb_type_creator19make_gdb_type_flagsEPK22tdesc_type_with_fieldsE19__PRETTY_FUNCTION__"; htab_hash_string is currently 4.35% + 7.98% (rehashing) of gdb startup when attaching to Chrome's content_shell. An additional 5.21% is spent in msymbol_hash, which does not use this hash function. Unfortunately, since it has to lowercase the string, it can't use this hash function. BM_msymbol_hash 52 ns 52 ns 13281495 It may be worth investigating if strlen+XXHash is still faster than htab_hash_string, which would make it easier to use in more places. Debian ships xxhash as libxxhash{0,-dev}. Fedora ships it as xxhash-devel. gdb/ChangeLog: 2019-10-22 Christian Biesinger * Makefile.in: Link with libxxhash. * config.in: Regenerate. * configure: Regenerate. * configure.ac: Search for libxxhash. * utils.c (fast_hash): Use xxhash if present. Change-Id: Icab218388b9f829522ed3977f04301ae6d4fc4ca --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bbf5d0897dc..3fac7952add 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,11 @@ +2019-10-22 Christian Biesinger + + * Makefile.in: Link with libxxhash. + * config.in: Regenerate. + * configure: Regenerate. + * configure.ac: Search for libxxhash. + * utils.c (fast_hash): Use xxhash if present. + 2019-10-22 Christian Biesinger * utils.h (fast_hash): New function. diff --git a/gdb/Makefile.in b/gdb/Makefile.in index b6caa2c220b..553b3ffdc4c 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -187,10 +187,14 @@ LIBEXPAT = @LIBEXPAT@ # Where is lzma? This will be empty if lzma was not available. LIBLZMA = @LIBLZMA@ -# Where is libbabeltrace? This will be empty if lbabeltrace was not +# Where is libbabeltrace? This will be empty if libbabeltrace was not # available. LIBBABELTRACE = @LIBBABELTRACE@ +# Where is libxxhash? This will be empty if libxxhash was not +# available. +LIBXXHASH = @LIBXXHASH@ + # Where is libipt? This will be empty if libipt was not available. LIBIPT = @LIBIPT@ @@ -597,7 +601,7 @@ CLIBS = $(SIM) $(READLINE) $(OPCODES) $(BFD) $(LIBCTF) $(ZLIB) \ @LIBS@ @GUILE_LIBS@ @PYTHON_LIBS@ \ $(LIBEXPAT) $(LIBLZMA) $(LIBBABELTRACE) $(LIBIPT) \ $(LIBIBERTY) $(WIN32LIBS) $(LIBGNU) $(LIBICONV) $(LIBMPFR) \ - $(SRCHIGH_LIBS) + $(SRCHIGH_LIBS) $(LIBXXHASH) CDEPS = $(NAT_CDEPS) $(SIM) $(BFD) $(READLINE_DEPS) $(LIBCTF) \ $(OPCODES) $(INTL_DEPS) $(LIBIBERTY) $(CONFIG_DEPS) $(LIBGNU) diff --git a/gdb/config.in b/gdb/config.in index 26ca02f6a3e..da365a7fc82 100644 --- a/gdb/config.in +++ b/gdb/config.in @@ -255,6 +255,9 @@ /* Define to 1 if you have the header file. */ #undef HAVE_LIBUNWIND_IA64_H +/* Define if you have the xxhash library. */ +#undef HAVE_LIBXXHASH + /* Define to 1 if you have the header file. */ #undef HAVE_LINUX_ELF_H diff --git a/gdb/configure b/gdb/configure index 737b426058c..ae8e451e760 100755 --- a/gdb/configure +++ b/gdb/configure @@ -628,6 +628,9 @@ GDB_TRANSFORM_NAME XSLTPROC NM_H GDB_NM_FILE +LTLIBXXHASH +LIBXXHASH +HAVE_LIBXXHASH LTLIBBABELTRACE LIBBABELTRACE HAVE_LIBBABELTRACE @@ -898,6 +901,8 @@ enable_sim enable_gdbserver with_babeltrace with_libbabeltrace_prefix +with_xxhash +with_libxxhash_prefix enable_unit_tests ' ac_precious_vars='build_alias @@ -1628,6 +1633,9 @@ Optional Packages: --with-babeltrace include babeltrace support (auto/yes/no) --with-libbabeltrace-prefix[=DIR] search for libbabeltrace in DIR/include and DIR/lib --without-libbabeltrace-prefix don't search for libbabeltrace in includedir and libdir + --with-xxhash use libxxhash for hashing (faster) (auto/yes/no) + --with-libxxhash-prefix[=DIR] search for libxxhash in DIR/include and DIR/lib + --without-libxxhash-prefix don't search for libxxhash in includedir and libdir Some influential environment variables: CC C compiler command @@ -17557,6 +17565,495 @@ $as_echo "$as_me: WARNING: babeltrace is missing or unusable; GDB is unable to r fi fi +# Check for xxhash + +# Check whether --with-xxhash was given. +if test "${with_xxhash+set}" = set; then : + withval=$with_xxhash; +else + with_xxhash=auto +fi + + +if test "x$with_xxhash" != "xno"; then + + + + + + + + + use_additional=yes + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + + eval additional_includedir=\"$includedir\" + eval additional_libdir=\"$libdir\" + + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + +# Check whether --with-libxxhash-prefix was given. +if test "${with_libxxhash_prefix+set}" = set; then : + withval=$with_libxxhash_prefix; + if test "X$withval" = "Xno"; then + use_additional=no + else + if test "X$withval" = "X"; then + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + + eval additional_includedir=\"$includedir\" + eval additional_libdir=\"$libdir\" + + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + else + additional_includedir="$withval/include" + additional_libdir="$withval/lib" + fi + fi + +fi + + LIBXXHASH= + LTLIBXXHASH= + INCXXHASH= + rpathdirs= + ltrpathdirs= + names_already_handled= + names_next_round='xxhash ' + while test -n "$names_next_round"; do + names_this_round="$names_next_round" + names_next_round= + for name in $names_this_round; do + already_handled= + for n in $names_already_handled; do + if test "$n" = "$name"; then + already_handled=yes + break + fi + done + if test -z "$already_handled"; then + names_already_handled="$names_already_handled $name" + uppername=`echo "$name" | sed -e 'y|abcdefghijklmnopqrstuvwxyz./-|ABCDEFGHIJKLMNOPQRSTUVWXYZ___|'` + eval value=\"\$HAVE_LIB$uppername\" + if test -n "$value"; then + if test "$value" = yes; then + eval value=\"\$LIB$uppername\" + test -z "$value" || LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$value" + eval value=\"\$LTLIB$uppername\" + test -z "$value" || LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }$value" + else + : + fi + else + found_dir= + found_la= + found_so= + found_a= + if test $use_additional = yes; then + if test -n "$shlibext" && test -f "$additional_libdir/lib$name.$shlibext"; then + found_dir="$additional_libdir" + found_so="$additional_libdir/lib$name.$shlibext" + if test -f "$additional_libdir/lib$name.la"; then + found_la="$additional_libdir/lib$name.la" + fi + else + if test -f "$additional_libdir/lib$name.$libext"; then + found_dir="$additional_libdir" + found_a="$additional_libdir/lib$name.$libext" + if test -f "$additional_libdir/lib$name.la"; then + found_la="$additional_libdir/lib$name.la" + fi + fi + fi + fi + if test "X$found_dir" = "X"; then + for x in $LDFLAGS $LTLIBXXHASH; do + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + eval x=\"$x\" + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + case "$x" in + -L*) + dir=`echo "X$x" | sed -e 's/^X-L//'` + if test -n "$shlibext" && test -f "$dir/lib$name.$shlibext"; then + found_dir="$dir" + found_so="$dir/lib$name.$shlibext" + if test -f "$dir/lib$name.la"; then + found_la="$dir/lib$name.la" + fi + else + if test -f "$dir/lib$name.$libext"; then + found_dir="$dir" + found_a="$dir/lib$name.$libext" + if test -f "$dir/lib$name.la"; then + found_la="$dir/lib$name.la" + fi + fi + fi + ;; + esac + if test "X$found_dir" != "X"; then + break + fi + done + fi + if test "X$found_dir" != "X"; then + LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-L$found_dir -l$name" + if test "X$found_so" != "X"; then + if test "$enable_rpath" = no || test "X$found_dir" = "X/usr/lib"; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so" + else + haveit= + for x in $ltrpathdirs; do + if test "X$x" = "X$found_dir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + ltrpathdirs="$ltrpathdirs $found_dir" + fi + if test "$hardcode_direct" = yes; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so" + else + if test -n "$hardcode_libdir_flag_spec" && test "$hardcode_minus_L" = no; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so" + haveit= + for x in $rpathdirs; do + if test "X$x" = "X$found_dir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + rpathdirs="$rpathdirs $found_dir" + fi + else + haveit= + for x in $LDFLAGS $LIBXXHASH; do + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + eval x=\"$x\" + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + if test "X$x" = "X-L$found_dir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-L$found_dir" + fi + if test "$hardcode_minus_L" != no; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_so" + else + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-l$name" + fi + fi + fi + fi + else + if test "X$found_a" != "X"; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$found_a" + else + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-L$found_dir -l$name" + fi + fi + additional_includedir= + case "$found_dir" in + */lib | */lib/) + basedir=`echo "X$found_dir" | sed -e 's,^X,,' -e 's,/lib/*$,,'` + additional_includedir="$basedir/include" + ;; + esac + if test "X$additional_includedir" != "X"; then + if test "X$additional_includedir" != "X/usr/include"; then + haveit= + if test "X$additional_includedir" = "X/usr/local/include"; then + if test -n "$GCC"; then + case $host_os in + linux*) haveit=yes;; + esac + fi + fi + if test -z "$haveit"; then + for x in $CPPFLAGS $INCXXHASH; do + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + eval x=\"$x\" + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + if test "X$x" = "X-I$additional_includedir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + if test -d "$additional_includedir"; then + INCXXHASH="${INCXXHASH}${INCXXHASH:+ }-I$additional_includedir" + fi + fi + fi + fi + fi + if test -n "$found_la"; then + save_libdir="$libdir" + case "$found_la" in + */* | *\\*) . "$found_la" ;; + *) . "./$found_la" ;; + esac + libdir="$save_libdir" + for dep in $dependency_libs; do + case "$dep" in + -L*) + additional_libdir=`echo "X$dep" | sed -e 's/^X-L//'` + if test "X$additional_libdir" != "X/usr/lib"; then + haveit= + if test "X$additional_libdir" = "X/usr/local/lib"; then + if test -n "$GCC"; then + case $host_os in + linux*) haveit=yes;; + esac + fi + fi + if test -z "$haveit"; then + haveit= + for x in $LDFLAGS $LIBXXHASH; do + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + eval x=\"$x\" + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + if test "X$x" = "X-L$additional_libdir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + if test -d "$additional_libdir"; then + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-L$additional_libdir" + fi + fi + haveit= + for x in $LDFLAGS $LTLIBXXHASH; do + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + eval x=\"$x\" + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + if test "X$x" = "X-L$additional_libdir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + if test -d "$additional_libdir"; then + LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-L$additional_libdir" + fi + fi + fi + fi + ;; + -R*) + dir=`echo "X$dep" | sed -e 's/^X-R//'` + if test "$enable_rpath" != no; then + haveit= + for x in $rpathdirs; do + if test "X$x" = "X$dir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + rpathdirs="$rpathdirs $dir" + fi + haveit= + for x in $ltrpathdirs; do + if test "X$x" = "X$dir"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + ltrpathdirs="$ltrpathdirs $dir" + fi + fi + ;; + -l*) + names_next_round="$names_next_round "`echo "X$dep" | sed -e 's/^X-l//'` + ;; + *.la) + names_next_round="$names_next_round "`echo "X$dep" | sed -e 's,^X.*/,,' -e 's,^lib,,' -e 's,\.la$,,'` + ;; + *) + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$dep" + LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }$dep" + ;; + esac + done + fi + else + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }-l$name" + LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-l$name" + fi + fi + fi + done + done + if test "X$rpathdirs" != "X"; then + if test -n "$hardcode_libdir_separator"; then + alldirs= + for found_dir in $rpathdirs; do + alldirs="${alldirs}${alldirs:+$hardcode_libdir_separator}$found_dir" + done + acl_save_libdir="$libdir" + libdir="$alldirs" + eval flag=\"$hardcode_libdir_flag_spec\" + libdir="$acl_save_libdir" + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$flag" + else + for found_dir in $rpathdirs; do + acl_save_libdir="$libdir" + libdir="$found_dir" + eval flag=\"$hardcode_libdir_flag_spec\" + libdir="$acl_save_libdir" + LIBXXHASH="${LIBXXHASH}${LIBXXHASH:+ }$flag" + done + fi + fi + if test "X$ltrpathdirs" != "X"; then + for found_dir in $ltrpathdirs; do + LTLIBXXHASH="${LTLIBXXHASH}${LTLIBXXHASH:+ }-R$found_dir" + done + fi + + + ac_save_CPPFLAGS="$CPPFLAGS" + + for element in $INCXXHASH; do + haveit= + for x in $CPPFLAGS; do + + acl_save_prefix="$prefix" + prefix="$acl_final_prefix" + acl_save_exec_prefix="$exec_prefix" + exec_prefix="$acl_final_exec_prefix" + eval x=\"$x\" + exec_prefix="$acl_save_exec_prefix" + prefix="$acl_save_prefix" + + if test "X$x" = "X$element"; then + haveit=yes + break + fi + done + if test -z "$haveit"; then + CPPFLAGS="${CPPFLAGS}${CPPFLAGS:+ }$element" + fi + done + + + { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libxxhash" >&5 +$as_echo_n "checking for libxxhash... " >&6; } +if ${ac_cv_libxxhash+:} false; then : + $as_echo_n "(cached) " >&6 +else + + ac_save_LIBS="$LIBS" + LIBS="$LIBS $LIBXXHASH" + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ +#include +int +main () +{ +XXH32("foo", 3, 0); + + ; + return 0; +} +_ACEOF +if ac_fn_c_try_link "$LINENO"; then : + ac_cv_libxxhash=yes +else + ac_cv_libxxhash=no +fi +rm -f core conftest.err conftest.$ac_objext \ + conftest$ac_exeext conftest.$ac_ext + LIBS="$ac_save_LIBS" + +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_libxxhash" >&5 +$as_echo "$ac_cv_libxxhash" >&6; } + if test "$ac_cv_libxxhash" = yes; then + HAVE_LIBXXHASH=yes + +$as_echo "#define HAVE_LIBXXHASH 1" >>confdefs.h + + { $as_echo "$as_me:${as_lineno-$LINENO}: checking how to link with libxxhash" >&5 +$as_echo_n "checking how to link with libxxhash... " >&6; } + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $LIBXXHASH" >&5 +$as_echo "$LIBXXHASH" >&6; } + else + HAVE_LIBXXHASH=no + CPPFLAGS="$ac_save_CPPFLAGS" + LIBXXHASH= + LTLIBXXHASH= + fi + + + + + + + if test "$HAVE_LIBXXHASH" != yes; then + if test "$with_xxhash" = yes; then + as_fn_error $? "xxhash is missing or unusable" "$LINENO" 5 + fi + fi + if test "x$with_xxhash" = "xauto"; then + with_xxhash="$HAVE_LIBXXHASH" + fi +fi + +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to use xxhash" >&5 +$as_echo_n "checking whether to use xxhash... " >&6; } +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $with_xxhash" >&5 +$as_echo "$with_xxhash" >&6; } + NM_H= rm -f nm.h if test "${nativefile}" != ""; then diff --git a/gdb/configure.ac b/gdb/configure.ac index dbe01509b91..629750210c6 100644 --- a/gdb/configure.ac +++ b/gdb/configure.ac @@ -2217,6 +2217,29 @@ else fi fi +# Check for xxhash +AC_ARG_WITH(xxhash, + AC_HELP_STRING([--with-xxhash], [use libxxhash for hashing (faster) (auto/yes/no)]), + [], [with_xxhash=auto]) + +if test "x$with_xxhash" != "xno"; then + AC_LIB_HAVE_LINKFLAGS([xxhash], [], + [#include ], + [XXH32("foo", 3, 0); + ]) + if test "$HAVE_LIBXXHASH" != yes; then + if test "$with_xxhash" = yes; then + AC_MSG_ERROR([xxhash is missing or unusable]) + fi + fi + if test "x$with_xxhash" = "xauto"; then + with_xxhash="$HAVE_LIBXXHASH" + fi +fi + +AC_MSG_CHECKING([whether to use xxhash]) +AC_MSG_RESULT([$with_xxhash]) + NM_H= rm -f nm.h if test "${nativefile}" != ""; then diff --git a/gdb/utils.c b/gdb/utils.c index 3afb8e5945f..1b62e55b57e 100644 --- a/gdb/utils.c +++ b/gdb/utils.c @@ -36,6 +36,10 @@ #include #endif +#ifdef HAVE_LIBXXHASH +#include +#endif + #include #include "gdbcmd.h" #include "serial.h" diff --git a/gdb/utils.h b/gdb/utils.h index 478c485e664..a8ad9d9c862 100644 --- a/gdb/utils.h +++ b/gdb/utils.h @@ -574,7 +574,11 @@ extern void copy_bitwise (gdb_byte *dest, ULONGEST dest_offset, static inline unsigned int fast_hash (const char* str, size_t len) { +#ifdef HAVE_LIBXXHASH + return XXH64 (str, len, 0); +#else return iterative_hash (str, len, 0); +#endif } #endif /* UTILS_H */