[fedt@yam]# time php -r 'for($i=0;$i<1000000;$i++) {$str="t\t \r\re s t\n";preg_match("/\s*t\s*e\s*s\s*t\s*/",$str);}'

real    0m4.031s
user    0m3.789s
sys     0m0.203s
[fedt@yam]# time php -r 'for($i=0;$i<1000000;$i++){$ws=array(" ","\t","\n","\r");$str="t\t \r\re s t\n";strstr(str_replace($ws,"",$str),"test");}'

real    0m9.217s
user    0m9.125s
sys     0m0.016s