On Fri, 8 Jun 2012 09:23:16 -0500
Strake <strake888_AT_gmail.com> wrote:
> On 08/06/2012, Ethan Grammatikidis <eekee57_AT_fastmail.fm> wrote:
> > On the linked page, Johan Petersson wrote:
> >
> >> It turns out, though, that system calls invoked via interrupts are
> >> remarkably slow on the more recent members of the x86 processor
> >> family. An int 0x80 system call can be as much as an order of
> >> magnitude slower on a 2 GHz Pentium 4 than on an 850 MHz Pentium III.
> >
> > Will linux-vdso or linux-gate be properly used by a statically linked
> > binary? Does it perhaps require /lib/ld-linux.so to link it in?
> >
> > I ask because I have some reason to believe syscall performance is
> > important if you want to work in the unix way, and doubly so if you
> > want a suckless system. Petersson here describes an order of magnitude
> > difference in syscall performance. I'm not sure of my conclusion but
> > it's something to keep an eye on, perhaps timing the piping of data in
> > both static and conventional Linux systems on the same hardware.
>
> On my x86 machine:
>
> $ cat test.c
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <unistd.h>
>
> int size = 1<<18;
> int n = 1<<16;
>
> void main () {
> char x[size];
> int ii;
>
> int ifd = open ("/dev/zero", O_RDONLY);
> int ofd = open ("/dev/null", O_WRONLY);
>
> for (ii = 0; ii < n; ii++) if (read (ifd, x, size) < 0 ||
> write (ofd, x, size) < 0) exit (1);
> }
> $ ls -l $(which cc)
> lrwxrwxrwx 1 root root 3 May 7 01:19 /usr/bin/cc -> gcc
> $ cc test.c && ldd a.out
> linux-vdso.so.1 => (0x00007fffbfbff000)
> libc.so.6 => /lib/libc.so.6 (0x00007faf905f7000)
> /lib/ld-linux-x86-64.so.2 (0x00007faf90998000)
> $ time ./a.out
> ./a.out 0.01s user 3.13s system 99% cpu 3.144 total
> $ cc -static test.c && ldd a.out
> not a dynamic executable
> $ time ./a.out
> ./a.out 0.00s user 3.14s system 100% cpu 3.145 total
>
> No worries, it seems.
>
> Cheers,
> strake
>
Awesome! Thanks for testing
--
This is obviously some strange usage of the
word "simple" that I was previously unaware of.
Received on Mon Jun 11 2012 - 18:29:01 CEST