illumos gate

wrote test program similar to those in previous ticket, but copying conversion logic from uniqtime. I originally tried copying the entire uniqtime function but had issues with tracking down some function calls used which I think are only available in kernel, and specialized for certain archs (specifically gethrestime). That code was not used in the relevant bits tested, so I chose to just focus the test on the conversion code which I intend to change:

#define _FAKE_KERNEL
#include <stdio.h>
#include <sys/kmem.h>
#include <sys/time.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>

#define TESTCOUNT 10000000

void
conv_new(timestruc_t ts, struct timeval *tv)
{
    time_t sec;
    int usec, nsec;

    usec = NSEC2USEC(ts.tv_nsec);
    sec = ts.tv_sec;

    tv->tv_sec = sec;
    tv->tv_usec = usec;
}

void
conv_old(timestruc_t ts, struct timeval *tv)
{
    time_t sec;
    int usec, nsec;

    /*
     * Fast algorithm to convert nsec to usec -- see hrt2ts()
     * in common/os/timers.c for a full description.
     */
    nsec = ts.tv_nsec;
    usec = nsec + (nsec >> 2);
    usec = nsec + (usec >> 1);
    usec = nsec + (usec >> 2);
    usec = nsec + (usec >> 4);
    usec = nsec - (usec >> 3);
    usec = nsec + (usec >> 2);
    usec = nsec + (usec >> 3);
    usec = nsec + (usec >> 4);
    usec = nsec + (usec >> 1);
    usec = nsec + (usec >> 6);
    usec = usec >> 10;
    sec = ts.tv_sec;

    tv->tv_sec = sec;
    tv->tv_usec = usec;
}

void
test_conv(void (*f)(timestruc_t, struct timeval *), const char * name) {
    timespec_t start, end;
    uint64_t diff;
    struct timeval tv;
    timestruc_t ts;

    clock_gettime(CLOCK_MONOTONIC, &start);
    ts.tv_sec = start.tv_sec;
    ts.tv_nsec = start.tv_nsec;
    for (int i=0; i < TESTCOUNT; i++) {
        f(ts, &tv);
    }
    clock_gettime(CLOCK_MONOTONIC, &end);
    if (end.tv_nsec < start.tv_nsec) {
        end.tv_sec -= 1;
        end.tv_nsec += NANOSEC;
    }
    diff = end.tv_nsec - start.tv_nsec;
    diff += (end.tv_sec - start.tv_sec) * NANOSEC;
    printf("%s out: %ld %ld\n", name, tv.tv_sec, tv.tv_usec);
    printf("%s: %lld for %d iterations (%lldns per)\n", name, diff, TESTCOUNT, diff/TESTCOUNT);
}

int 
main(int argc, char** argv) {
    test_conv(conv_old, "uniqtime_conv_old");
    test_conv(conv_new, "uniqtime_conv_new");
}

with following results run inside omnios qemu guest on an i7

host % qemu-system-x86_64 -cpu host -enable-kvm -m 2048 \
    -hda omnios.qcow2 \
    -nic user,model=e1000 \
    -boot d -smp 2
omnios % uname -a
SunOS omnios 5.11 omnios-master-cc133161da i86pc i386 i86pc
omnios % gcc -O2 -m64 -o test_64 test_conv.c && ./test_64
uniqtime_conv_old out: 58584 384109
uniqtime_conv_old: 34933684 for 10000000 iterations (3ns per)
uniqtime_conv_new out: 58584 419166
uniqtime_conv_new: 18413529 for 10000000 iterations (1ns per)
omnios % gcc -O2 -m32 -o test_32 test_conv.c && ./test_32
uniqtime_conv_old out: 58591 231829
uniqtime_conv_old: 55962797 for 10000000 iterations (5ns per)
uniqtime_conv_new out: 58591 287918
uniqtime_conv_new: 29201299 for 10000000 iterations (2ns per)

looks similar to previous tests in #7709 , but test+results added for sanity checking

shua ll wrote in #note-3:

with following results run inside omnios qemu guest on an i7
[...]

tsoome@openindiana:~$ gcc -O2 -m64 -o test_64 uniqtime.c && ./test_64
uniqtime.c: In function 'test_conv':
uniqtime.c:58:5: warning: implicit declaration of function 'clock_gettime' [-Wimplicit-function-declaration]
     clock_gettime(CLOCK_MONOTONIC, &start);
     ^~~~~~~~~~~~~
uniqtime_conv_old out: 11939965 851099
uniqtime_conv_old: 201545879 for 10000000 iterations (20ns per)
uniqtime_conv_new out: 11939966 52851
uniqtime_conv_new: 278173248 for 10000000 iterations (27ns per)
tsoome@openindiana:~$ gcc -O2 -m32 -o test_32 uniqtime.c && ./test_32
uniqtime.c: In function 'test_conv':
uniqtime.c:58:5: warning: implicit declaration of function 'clock_gettime' [-Wimplicit-function-declaration]
     clock_gettime(CLOCK_MONOTONIC, &start);
     ^~~~~~~~~~~~~
uniqtime_conv_old out: 11939983 91287
uniqtime_conv_old: 257926684 for 10000000 iterations (25ns per)
uniqtime_conv_new out: 11939983 349546
uniqtime_conv_new: 228006663 for 10000000 iterations (22ns per)
tsoome@openindiana:~$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/gcc/7/lib/gcc/sparc-sun-solaris2.11/7.5.0/lto-wrapper
Target: sparc-sun-solaris2.11
Configured with: /code/oi-userland/components/developer/gcc-7/gcc-gcc-7.5.0-oi-0/configure CC=/usr/gcc/7/bin/gcc CXX=/usr/gcc/7/bin/g++ F77=/usr/gcc/7/bin/gfortran FC=/usr/gcc/7/bin/gfortran CFLAGS=-O2 CXXFLAGS=-O2 FFLAGS='  -O3 -mno-app-regs' FCFLAGS=-O2 LDFLAGS=-m32 PKG_CONFIG_PATH=/usr/lib/pkgconfig --prefix=/usr/gcc/7 --mandir=/usr/gcc/7/share/man --bindir=/usr/gcc/7/bin --libdir=/usr/gcc/7/lib --sbindir=/usr/gcc/7/sbin --sbindir=/usr/gcc/7/bin --libdir=/usr/gcc/7/lib --libexecdir=/usr/gcc/7/lib --host sparc-sun-solaris2.11 --build sparc-sun-solaris2.11 --target sparc-sun-solaris2.11 --with-pkgversion='OpenIndiana 7.5.0-il-0' --with-bugurl=https://bugs.openindiana.org --without-gnu-ld --with-ld=/usr/bin/ld --with-build-time-tools=/usr/gnu/sparc-sun-solaris2.11/bin --without-gnu-as --with-as=/usr/bin/as LDFLAGS=-R/usr/gcc/7/lib --enable-plugins --enable-objc-gc --enable-languages=c,c++,fortran,lto,objc --disable-libitm enable_frame_pointer=yes
Thread model: posix
gcc version 7.5.0 (OpenIndiana 7.5.0-il-0) 
tsoome@openindiana:~$ uname -a
SunOS openindiana 5.11 illumos-6dcbfae4aa sun4v sparc sun4v
tsoome@openindiana:~$