> >Omar Khan wrote: >> Anthony Liguori <[EMAIL PROTECTED]> writes: >> >> >>> I've got a patch that should appear in virtbench soon that actually >>> measures vmcall latency. >>> >>> http://ozlabs.org/~rusty/virtbench >>> >>> >> >> Thanks Anthony. I have a newbie question though. In the vmcall function >in the >> patch: >> >> +static int vmcall(unsigned int cmd) >> +{ >> + signal(SIGILL, illegal_instruction); >> + asm volatile(".byte 0x0F,0x01,0xC1,0xC3\n" ::"a"(cmd)); >> + signal(SIGILL, SIG_DFL); >> + >> + return 0; >> +} >> >> Why do you have the ret opcode '0xC3' with the vmcall? >> > >Because I lazily copied from KVM instead of looking them up. I figured >0xC3 was a NOP. Will fix.
0xC3 is return from the hypercall. Btw 0x90 is nop. >From looking in the code I saw that you fork a process and wait for him to finish. Isn't that increases the time counted for the vmmcall? Maybe somewhere the process overhead is measured and afterwards this time is decreased? > >> Thanks >> >> Omar >> >> >> ------------------------------------------------------------------------ - >> Take Surveys. Earn Cash. Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to share >your >> opinions on IT & business topics through brief surveys-and earn cash >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDE V >> _______________________________________________ >> kvm-devel mailing list >> kvm-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/kvm-devel >> >> > > >----------------------------------------------------------------------- -- >Take Surveys. Earn Cash. Influence the Future of IT >Join SourceForge.net's Techsay panel and you'll get the chance to share >your >opinions on IT & business topics through brief surveys-and earn cash >http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVD EV >_______________________________________________ >kvm-devel mailing list >kvm-devel@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/kvm-devel ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
