我在RHEL5的Time :: HiRes中遇到了非常奇怪的行为。 由于Time :: HiRes在Perl标准安装中,并且基本上是gettimeofday系统调用的一个包装,我倾向于将手指指向操作系统而不是模块,甚至是perl。
这是我的示例代码:
#!/usr/bin/perl use Time::HiRes; use LWP::Simple; for (1..10) { my $started = [Time::HiRes::gettimeofday]; # do something that we can expect to take time, but not too much time my $throwaway = get("http://localhost/"); my $elapsed = Time::HiRes::tv_interval($started); print "$elapsed\n"; sleep(1); }
在我的Mac上运行这个提供了完全一致的结果:
0.025934 0.000642 0.000716 0.001003 0.001026 0.000733 0.000815 0.000646 0.000629 0.000793
但是,在我的RHEL5服务器上运行产生了不全面的效果:
0.034182 0.015998 0.06415 0.015523 -0.000379 0 0 0 0 0
特别注意第五个结果!
以防万一,这是服务器上的perl -V的结果:
Summary of my perl5 (revision 5 version 8 subversion 8) configuration: Platform: osname=linux, osvers=2.6.18-92.1.6.el5, archname=i686-linux uname='linux 188186.sexton.article7.co.uk 2.6.18-92.1.6.el5 #1 smp fri jun 20 02:36:16 edt 2008 i686 athlon i386 gnulinux ' config_args='-des -Dprefix=/usr/local' hint=previous, useposix=true, d_sigaction=define usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef useperlio=define d_sfio=undef uselargefiles=define usesocks=undef use64bitint=undef use64bitall=undef uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='cc', ccflags ='-fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2', cppflags='-fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -fno-strict-aliasing -pipe -Wdeclaration-after-statement -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64' ccversion='', gccversion='4.1.2 20071124 (Red Hat 4.1.2-42)', gccosandvers='' intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12 ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8 alignbytes=4, prototype=define Linker and Libraries: ld='cc', ldflags =' -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib libs=-lnsl -ldl -lm -lcrypt -lutil -lc perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc libc=/lib/libc-2.5.so, so=so, useshrplib=false, libperl=libperl.a gnulibc_version='2.5' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E' cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib' Characteristics of this binary (from libperl): Compile-time options: PERL_MALLOC_WRAP USE_LARGE_FILES USE_PERLIO Built under linux Compiled at Sep 15 2008 15:05:12 @INC: /usr/local/perl/5.8.8/lib/5.8.8/i686-linux /usr/local/perl/5.8.8/lib/5.8.8 /usr/local/perl/5.8.8/lib/site_perl/5.8.8/i686-linux /usr/local/perl/5.8.8/lib/site_perl/5.8.8 /usr/local/perl/5.8.8/lib/site_perl .
这是一个已知的问题吗? 任何想法非常感激地接受。
看一下
https://stackoverflow.com/questions/656537/is-there-a-better-way-to-determine-elapsed-time-in-perl
最后的评论意味着它不仅仅是你这个问题
难道你不能仅仅因为你的系统如此之快而在负面的时候返回结果而感到高兴吗? :)所有的开玩笑,我们在虚拟化环境中RHEL5有奇怪的时钟漂移问题; 可能涉及到你的问题?