mirror of
git://git.code.sf.net/p/cdesktopenv/code
synced 2025-03-09 15:50:02 +00:00
396b388e1f
This commit fixes an issue I found in the subshell $RANDOM
reseeding code.
The main issue is a performance regression in the shbench fibonacci
benchmark, introduced in commit af6a32d1. Performance dropped in
this benchmark because $RANDOM is always reseeded and restored,
even when it's never used in a subshell. Performance results from
before and after this performance fix (results are on Linux with
CC=gcc and CCFLAGS='-O2 -D_std_malloc'):
$ ./shbench -b bench/fibonacci.ksh -l 100 ./ksh-0f06a2e ./ksh-af6a32d ./ksh-f31e368 ./ksh-randfix
benchmarking ./ksh-0f06a2e, ./ksh-af6a32d, ./ksh-f31e368, ./ksh-randfix ...
*** fibonacci.ksh ***
# ./ksh-0f06a2e # Recent version of ksh93u+m
# ./ksh-af6a32d # Commit that introduced the regression
# ./ksh-f31e368 # Commit without the regression
# ./ksh-randfix # Ksh93u+m with this patch applied
-------------------------------------------------------------------------------------------------
name ./ksh-0f06a2e ./ksh-af6a32d ./ksh-f31e368 ./ksh-randfix
-------------------------------------------------------------------------------------------------
fibonacci.ksh 0.481 [0.459-0.515] 0.472 [0.455-0.504] 0.396 [0.380-0.442] 0.407 [0.385-0.439]
-------------------------------------------------------------------------------------------------
src/cmd/ksh93/include/variables.h,
src/cmd/ksh93/sh/{init,subshell}.c:
- Rather than reseed $RANDOM every time a subshell is created, add
a sh_save_rand_seed() function that does this only when the
$RANDOM variable is used in a subshell. This function is called
by the $RANDOM discipline functions nget_rand() and put_rand().
As a minor optimization, sh_save_rand_seed doesn't reseed if it's
called from put_rand().
- Because $RANDOM may have a seed of zero (i.e., RANDOM=0),
sp->rand_seed isn't enough to tell if $RANDOM has been reseeded.
Add sp->rand_state for this purpose.
- sh_subshell(): Only restore the former $RANDOM seed and state if
it is necessary to prevent a subshell leak.
src/cmd/ksh93/tests/variables.sh:
- Add two regression tests for bugs I ran into while making this
patch.
110 lines
4.6 KiB
C
110 lines
4.6 KiB
C
/***********************************************************************
|
|
* *
|
|
* This software is part of the ast package *
|
|
* Copyright (c) 1982-2011 AT&T Intellectual Property *
|
|
* Copyright (c) 2020-2021 Contributors to ksh 93u+m *
|
|
* and is licensed under the *
|
|
* Eclipse Public License, Version 1.0 *
|
|
* by AT&T Intellectual Property *
|
|
* *
|
|
* A copy of the License is available at *
|
|
* http://www.eclipse.org/org/documents/epl-v10.html *
|
|
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
|
|
* *
|
|
* Information and Software Systems Research *
|
|
* AT&T Research *
|
|
* Florham Park NJ *
|
|
* *
|
|
* David Korn <dgk@research.att.com> *
|
|
* *
|
|
***********************************************************************/
|
|
#pragma prototyped
|
|
|
|
#ifndef SH_VALNOD
|
|
|
|
#include <option.h>
|
|
#include "FEATURE/options"
|
|
#include "FEATURE/dynamic"
|
|
#include <nval.h>
|
|
|
|
/* used for RANDNOD ($RANDOM) */
|
|
struct rand
|
|
{
|
|
Namfun_t hdr;
|
|
unsigned int rand_seed;
|
|
int32_t rand_last;
|
|
};
|
|
extern void sh_reseed_rand(struct rand *);
|
|
extern void sh_save_rand_seed(struct rand *, int);
|
|
|
|
/* The following defines must be kept synchronous with shtab_variables[] in data/variables.c */
|
|
|
|
#define PATHNOD (shgd->bltin_nodes)
|
|
#define PS1NOD (shgd->bltin_nodes+1)
|
|
#define PS2NOD (shgd->bltin_nodes+2)
|
|
#define IFSNOD (shgd->bltin_nodes+3)
|
|
#define PWDNOD (shgd->bltin_nodes+4)
|
|
#define HOME (shgd->bltin_nodes+5)
|
|
#define MAILNOD (shgd->bltin_nodes+6)
|
|
#define REPLYNOD (shgd->bltin_nodes+7)
|
|
#define SHELLNOD (shgd->bltin_nodes+8)
|
|
#define EDITNOD (shgd->bltin_nodes+9)
|
|
#define MCHKNOD (shgd->bltin_nodes+10)
|
|
#define RANDNOD (shgd->bltin_nodes+11)
|
|
#define ENVNOD (shgd->bltin_nodes+12)
|
|
#define HISTFILE (shgd->bltin_nodes+13)
|
|
#define HISTSIZE (shgd->bltin_nodes+14)
|
|
#define HISTEDIT (shgd->bltin_nodes+15)
|
|
#define HISTCUR (shgd->bltin_nodes+16)
|
|
#define FCEDNOD (shgd->bltin_nodes+17)
|
|
#define CDPNOD (shgd->bltin_nodes+18)
|
|
#define MAILPNOD (shgd->bltin_nodes+19)
|
|
#define PS3NOD (shgd->bltin_nodes+20)
|
|
#define OLDPWDNOD (shgd->bltin_nodes+21)
|
|
#define VISINOD (shgd->bltin_nodes+22)
|
|
#define COLUMNS (shgd->bltin_nodes+23)
|
|
#define LINES (shgd->bltin_nodes+24)
|
|
#define PPIDNOD (shgd->bltin_nodes+25)
|
|
#define L_ARGNOD (shgd->bltin_nodes+26)
|
|
#define TMOUTNOD (shgd->bltin_nodes+27)
|
|
#define SECONDS (shgd->bltin_nodes+28)
|
|
#define LINENO (shgd->bltin_nodes+29)
|
|
#define OPTARGNOD (shgd->bltin_nodes+30)
|
|
#define OPTINDNOD (shgd->bltin_nodes+31)
|
|
#define PS4NOD (shgd->bltin_nodes+32)
|
|
#define FPATHNOD (shgd->bltin_nodes+33)
|
|
#define LANGNOD (shgd->bltin_nodes+34)
|
|
#define LCALLNOD (shgd->bltin_nodes+35)
|
|
#define LCCOLLNOD (shgd->bltin_nodes+36)
|
|
#define LCTYPENOD (shgd->bltin_nodes+37)
|
|
#define LCMSGNOD (shgd->bltin_nodes+38)
|
|
#define LCNUMNOD (shgd->bltin_nodes+39)
|
|
#define LCTIMENOD (shgd->bltin_nodes+40)
|
|
#define FIGNORENOD (shgd->bltin_nodes+41)
|
|
#define VERSIONNOD (shgd->bltin_nodes+42)
|
|
#define JOBMAXNOD (shgd->bltin_nodes+43)
|
|
#define DOTSHNOD (shgd->bltin_nodes+44)
|
|
#define ED_CHRNOD (shgd->bltin_nodes+45)
|
|
#define ED_COLNOD (shgd->bltin_nodes+46)
|
|
#define ED_TXTNOD (shgd->bltin_nodes+47)
|
|
#define ED_MODENOD (shgd->bltin_nodes+48)
|
|
#define SH_NAMENOD (shgd->bltin_nodes+49)
|
|
#define SH_SUBSCRNOD (shgd->bltin_nodes+50)
|
|
#define SH_VALNOD (shgd->bltin_nodes+51)
|
|
#define SH_VERSIONNOD (shgd->bltin_nodes+52)
|
|
#define SH_DOLLARNOD (shgd->bltin_nodes+53)
|
|
#define SH_MATCHNOD (shgd->bltin_nodes+54)
|
|
#define SH_COMMANDNOD (shgd->bltin_nodes+55)
|
|
#define SH_PATHNAMENOD (shgd->bltin_nodes+56)
|
|
#define SH_FUNNAMENOD (shgd->bltin_nodes+57)
|
|
#define SH_SUBSHELLNOD (shgd->bltin_nodes+58)
|
|
#define SH_LEVELNOD (shgd->bltin_nodes+59)
|
|
#define SH_LINENO (shgd->bltin_nodes+60)
|
|
#define SH_STATS (shgd->bltin_nodes+61)
|
|
#define SH_MATHNOD (shgd->bltin_nodes+62)
|
|
#define SH_JOBPOOL (shgd->bltin_nodes+63)
|
|
#define SH_PIDNOD (shgd->bltin_nodes+64)
|
|
#define SH_TILDENOD (shgd->bltin_nodes+65)
|
|
#define SHLVL (shgd->bltin_nodes+66)
|
|
|
|
#endif /* SH_VALNOD */
|