%s

// ============================================================================ // C servlet sample for the G-WAN Web Application Server (http://trustleap.ch/) // ---------------------------------------------------------------------------- // httpdate.c: benchmark HTTP-compliant dates formatting // // In comparison to the Windows system Wininet InternetTimeFromSystemTime() API // call, Linux clib calls are twice as fast (see the Windows 'bench.c' servlet) // but G-WAN's code is ALSO faster under Linux: 30x faster than Linux libc. // // That's why G-WAN offers function calls that are 'redundant' with the system. // ============================================================================ // imported functions: // get_reply(): get a pointer on the 'reply' dynamic buffer from the server // xbuf_cat(): like strcat(), but it works in the specified dynamic buffer // ---------------------------------------------------------------------------- #include "gwan.h" // G-WAN exported functions #include #include // ---------------------------------------------------------------------------- // using Linux clib calls to format an HTTP date, just like G-WAN's time2rfc() // ---------------------------------------------------------------------------- static char *httptime(time_t t, char *date) { time_t tt; if(t) tt = t; else tt = time(0); strftime(date, 31, "%a, %d %b %Y %H:%M:%S GMT", gmtime(&tt)); return date; } // ---------------------------------------------------------------------------- // Title of our HTML page static u8 title[] = "Benchmarking function calls (with CPU clock cycles)"; // Top of our HTML page static char top[]= "" "%s" "" "

%s

"; int main(int argc, char *argv[]) { char date[32]; u64 start, overh = 0; u32 i, rounds=10, ms_min = 0xffffffff, ms_ave = 0, ms_max = 0, sv_min = 0xffffffff, sv_max = 0, sv_ave = 0, t = time(0), z = 1; // create a dynamic buffer and get a pointer on the server response buffer xbuf_t *reply = get_reply(argv); // ---- format the top of our HTML page with a title xbuf_xcat(reply, top, title, title); // ---- find the CPU clock cycles count overhead so we can remove it later i=rounds; while(i--) start=cycles64(), overh=cycles64()-(start+z), overh--; // ------------------------------------------------------------------------- // benchmark the Linux clib function calls // ------------------------------------------------------------------------- // check that all function calls provide similar results memset(date, 0, sizeof(date)); httptime(t, date); xbuf_xcat(reply, "Linux clib calls: %s
", date); xbuf_cat(reply, "
" ""); // warm the cpu cache to get consistent values i = rounds * 2; while(i--) start = cycles64(), httptime(t, date); i = rounds; // now time it while(i--) { start = cycles64(); httptime(t, date); start = cycles64() - (start + overh); if(ms_min > start) ms_min = start; if(ms_max < start) ms_max = start; ms_ave += start; xbuf_xcat(reply, "", !(i & 1), start); } ms_ave /= rounds; xbuf_cat(reply, "

function	time
Linux clib calls	%u

"); // ------------------------------------------------------------------------- // benchmark G-WAN's "time2rfc(t, date);" function call // ------------------------------------------------------------------------- // check that all function calls provide similar results memset(date, 0, sizeof(date)); xbuf_xcat(reply, "
G-WAN time2rfc(): %s
", time2rfc(t, date)); xbuf_cat(reply, "
" ""); // warm the cpu cache to get consistent values i = rounds * 2; while(i--) start = cycles64(), time2rfc(t, date); i = rounds; // now time it while(i--) { start = cycles64(); time2rfc(t, date); start = cycles64() - (start + overh); if(sv_min > start) sv_min = start; if(sv_max < start) sv_max = start; sv_ave += start; xbuf_xcat(reply, "", !(i & 1), start); } sv_ave /= rounds; xbuf_cat(reply, "

function	time
G-WAN time2rfc()	%u

"); // ------------------------------------------------------------------------- // write how many CPU cycles these operations took // ------------------------------------------------------------------------- xbuf_xcat(reply, "
" "" "" "" "

function	max	average	min
Linux clib calls	%u	%u	%u
G-WAN time2rfc()	%u	%u	%u

" "

G-WAN's code scaled %.02f times " "better

", ms_max, ms_ave, ms_min, sv_max, sv_ave, sv_min, (double)ms_ave / (double)sv_ave); // ---- close our HTML page xbuf_cat(reply, "
"); return HTTP_200_OK; // return an HTTP code } // ============================================================================ // End of Source Code // ============================================================================