/*
 * Test null syscall performance
 *
 * Copyright (C) 2009-2015 Anton Blanchard, IBM
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#define NR_LOOPS 10000000

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/time.h>
#include <signal.h>

static volatile int soak_done;
unsigned long long clock_frequency;
unsigned long long timebase_frequency;
double timebase_multiplier;

static inline unsigned long long mftb(void)
{
	unsigned long low;

	asm volatile("mftb %0" : "=r" (low));

	return low;
}

static void sigalrm_handler(int unused)
{
	soak_done = 1;
}

/*
 * Use a timer instead of busy looping on clock_gettime() so we don't
 * pollute profiles with glibc and VDSO hits.
 */
static void cpu_soak_usecs(unsigned long usecs)
{
	struct itimerval val;

	memset(&val, 0, sizeof(val));
	val.it_value.tv_usec = usecs;

	signal(SIGALRM, sigalrm_handler);
	setitimer(ITIMER_REAL, &val, NULL);

	while (1) {
		if (soak_done)
			break;
	}

	signal(SIGALRM, SIG_DFL);
}

/*
 * This only works with recent kernels where cpufreq modifies
 * /proc/cpuinfo dynamically.
 */
static void get_proc_frequency(void)
{
	FILE *f;
	char line[128];
	char *p, *end;
	unsigned long v;
	double d;
	char *override;

	/* Try to get out of low power/low frequency mode */
	cpu_soak_usecs(0.25 * 1000000);

	f = fopen("/proc/cpuinfo", "r");
	if (f == NULL)
		return;

	timebase_frequency = 0;

	while (fgets(line, sizeof(line), f) != NULL) {
		if (strncmp(line, "timebase", 8) == 0) {
			p = strchr(line, ':');
			if (p != NULL) {
				v = strtoull(p + 1, &end, 0);
				if (end != p + 1)
					timebase_frequency = v;
			}
		}

		if (((strncmp(line, "clock", 5) == 0) ||
		     (strncmp(line, "cpu MHz", 7) == 0))) {
			p = strchr(line, ':');
			if (p != NULL) {
				d = strtod(p + 1, &end);
				if (end != p + 1) {
					/* Find fastest clock frequency */
					if ((d * 1000000ULL) > clock_frequency)
						clock_frequency = d * 1000000ULL;
				}
			}
		}
	}

	fclose(f);

	override = getenv("FREQUENCY");
	if (override)
		clock_frequency = strtoull(override, NULL, 10);

	if (timebase_frequency)
		timebase_multiplier = (double)clock_frequency
					/ timebase_frequency;
	else
		timebase_multiplier = 1;
}

static void do_null_syscall(unsigned long nr)
{
	unsigned long i;

	for (i = 0; i < nr; i++)
		getppid();
}

#define TIME(A, STR) \

int main(void)
{
	unsigned long tb_start, tb_now;
	struct timespec tv_start, tv_now;
	unsigned long long elapsed_ns, elapsed_tb;

	get_proc_frequency();

	clock_gettime(CLOCK_MONOTONIC, &tv_start);
	tb_start = mftb();

	do_null_syscall(NR_LOOPS);

	clock_gettime(CLOCK_MONOTONIC, &tv_now);
	tb_now = mftb();

	elapsed_ns = (tv_now.tv_sec - tv_start.tv_sec) * 1000000000ULL +
			(tv_now.tv_nsec - tv_start.tv_nsec);
	elapsed_tb = tb_now - tb_start;

	printf("%10.2f ns %10.2f cycles\n", (float)elapsed_ns / NR_LOOPS,
			(float)elapsed_tb * timebase_multiplier / NR_LOOPS);

	return 0;
}
option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-12-12 21:58:13 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2016-12-12 21:58:13 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/ehci-sh.c?id=e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba'>e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/host/ehci-sh.c?id=e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/'>f63906f41699c8e38af9d12b063e2ceab0286ef2</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/host/ehci-sh.c'>drivers/usb/host/ehci-sh.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/ehci-sh.c?id=e34bac726d27056081d0250c0e173e4b155aa340'>e34bac726d27056081d0250c0e173e4b155aa340</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/host/ehci-sh.c?id2=e34bac726d27056081d0250c0e173e4b155aa340'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/ehci-sh.c?id=868c97a846a73e937d835b09b8c885a69df50ec8'>868c97a846a73e937d835b09b8c885a69df50ec8</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/host/ehci-sh.c?id2=868c97a846a73e937d835b09b8c885a69df50ec8'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge tag 'docs-4.10' of git://git.lwn.net/linux<span class='decoration'><a class='deco' href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/ehci-sh.c?id=e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba'>HEAD</a><a class='branch-deco' href='/cgit.cgi/linux/net-next.git/log/drivers/usb/host/ehci-sh.c'>master</a></span></div><div class='commit-msg'>Pull documentation update from Jonathan Corbet:
 "These are the documentation changes for 4.10.

  It's another busy cycle for the docs tree, as the sphinx conversion
  continues. Highlights include:

   - Further work on PDF output, which remains a bit of a pain but
     should be more solid now.

   - Five more DocBook template files converted to Sphinx. Only 27 to
     go... Lots of plain-text files have also been converted and
     integrated.

   - Images in binary formats have been replaced with more
     source-friendly versions.

   - Various bits of organizational work, including the renaming of
     various files discussed at the kernel summit.

   - New documentation for the device_link mechanism.

  ... and, of course, lots of typo fixes and small updates"

* tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits)
  dma-buf: Extract dma-buf.rst
  Update Documentation/00-INDEX
  docs: 00-INDEX: document directories/files with no docs
  docs: 00-INDEX: remove non-existing entries
  docs: 00-INDEX: add missing entries for documentation files/dirs
  docs: 00-INDEX: consolidate process/ and admin-guide/ description
  scripts: add a script to check if Documentation/00-INDEX is sane
  Docs: change sh -&gt; awk in REPORTING-BUGS
  Documentation/core-api/device_link: Add initial documentation
  core-api: remove an unexpected unident
  ppc/idle: Add documentation for powersave=off
  Doc: Correct typo, "Introdution" =&gt; "Introduction"
  Documentation/atomic_ops.txt: convert to ReST markup
  Documentation/local_ops.txt: convert to ReST markup
  Documentation/assoc_array.txt: convert to ReST markup
  docs-rst: parse-headers.pl: cleanup the documentation
  docs-rst: fix media cleandocs target
  docs-rst: media/Makefile: reorganize the rules
  docs-rst: media: build SVG from graphviz files
  docs-rst: replace bayer.png by a SVG image
  ...
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/'>Diffstat</a> (limited to 'drivers/usb/host/ehci-sh.c')</div><table summary='diffstat' class='diffstat'>