On 28 November 2013 08:58, Glenn Fowler <glenn.s.fow...@gmail.com> wrote:
> here are some points of reference showing real user sys times
> these were manually sampled to pinpoint jumps in performance from 206 ksh
> binaries from 2006-11-22 through 2013-09-10
>
> ksh-2009-11-17 0m12.06s 0m11.82s 0m0.14s
> ksh-2009-12-04 0m13.84s 0m13.58s 0m0.16s
> ksh-2010-06-16 0m15.15s 0m14.92s 0m0.17s
> ksh-2010-11-16 0m14.06s 0m13.82s 0m0.16s
> ksh-2011-04-11 0m12.72s 0m12.44s 0m0.17s
> ksh-2011-06-21 0m12.58s 0m12.35s 0m0.15s
> ksh-2011-09-21 0m20.58s 0m20.27s 0m0.19s
> ksh-2013-04-11 0m23.40s 0m23.15s 0m0.17s
> ksh-2013-05-13 0m13.83s 0m13.61s 0m0.12s
> ksh-2013-05-31 0m14.15s 0m13.93s 0m0.11s
> ksh-2013-06-06 0m27.15s 0m26.87s 0m0.14s
>
>
>
> On Wed, Nov 27, 2013 at 5:38 PM, Lionel Cons <lionelcons1...@gmail.com>
> wrote:
>>
>> We've observing a *severe* performance regression between ksh
>> 2010-03-05 and 2013-10-08 on Solaris 11, AMD64, LANG is en_US.UTF-8:
>>
>> # prepare
>> $ timex seq 1400000 >xxx
>>
>> # run new ksh
>> $ timex ~/bin/ksh -c 'function nanosort { typeset -A a ; integer k=0;
>> while read i ; do key="$i$((k++))" ; a["$key"]="$i" ; done ; printf
>> "%s\n" "${a[@]}"
>> ; } ; print "${.sh.version}" ; nanosort <xxx >yyy'
>> Version AIJMP 93v- 2013-10-08
>>
>> real 32.59
>> user 32.19
>> sys 0.30
>>
>> # run old ksh - much faster
>> $ timex /bin/ksh -c 'function nanosort { typeset -A a ; integer k=0;
>> while read i ; do key="$i$((k++))" ; a["$key"]="$i" ; done ; printf
>> "%s\n" "${a[@]}" ; } ; print "${.sh.version}" ; nanosort <xxx >yyy'
>> Version JM 93t+ 2010-03-05
>>
>> real 14.59
>> user 13.92
>> sys 0.56
>>
>> Can anyone explain this? IO-wise the new ksh is better but consumes
>> much more CPU time, while the old ksh issues more IO requests but
>> consumes only half as much CPU time.
>>
>> Lionel
I looks that the problem is related to the function scope, without a
function scope the loop takes 24 seconds, and with function scope it
takes 32 seconds:
timex ~/bin/ksh -c 'nanosort() { typeset -A a ; integer k=0; while
read i ; do key="$i$((k++))" ; a["$key"]="$i" ; done ; printf "%s\n"
"${a[@]}" ; } ; print "${.sh.version}" ; nanosort <xxx >yyy'
Version AIJMP 93v- 2013-10-08
real 24.98
user 24.57
sys 0.32
timex ~/bin/ksh -c 'function nanosort { typeset -A a ; integer k=0;
while read i ; do key="$i$((k++))" ; a["$key"]="$i" ; done ; printf
"%s\n" "${a[@]}" ; } ; print "${.sh.version}" ; nanosort <xxx >yyy'
Version AIJMP 93v- 2013-10-08
real 32.79
user 32.39
sys 0.31
Lionel
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