Re: [PATCH] [v2] intel_frequency: A tool to manipulate Intel GPU frequency

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On Thu, Jan 15, 2015 at 02:00:06PM +0000, Dave Gordon wrote:
> On 12/01/15 03:35, Ben Widawsky wrote:
> > WARNING: very minimally tested
> > 
> > In general you should not need this tool. It's primary purpose is for
> > benchmarking, and for debugging performance issues.
> > 
> > For many kernel releases now sysfs has supported reading and writing the GPU
> > frequency. Therefore, this tool provides no new functionality. What it does
> > provide is an easy to package (for distros) tool that handles the most common
> > scenarios.
> > 
> > v2:
> > Get rid of -f from the usage message (Jordan)
> > Add space before [-s (Jordan)
> > Add a -c/--custom example (Jordan)
> > Add a setting for resetting to hardware default (Ken)
> > Replicate examples in commit message in the source code. (me)
> > 
> > Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx>
> > Reviewed-by: Jordan Justen <jordan.l.justen@xxxxxxxxx>
> > Cc: Kenneth Graunke <kenneth@xxxxxxxxxxxxx>
> 
> I think the syntax of some of these commands is rather strange;

It all uses standard POSIX commands to parse them. If you think the names are
bad, we can discuss that.

> also, it would be nicer to have consistent naming of inputs & outputs -
> specifically, the input name "eff" is related to the output tag "RP1".  Please
> pick one of the other.

Yes, this was laziness feel free to fix it.

> 
> And are all the examples below actually correct?
> 
> > Here are some sample usages:
> > $ sudo intel_frequency --get=cur,min,max,eff
> > cur: 200 MHz
> > min: 200 MHz
> > RP1: 200 MHz
> > max: 1200 MHz
> > 
> > $ sudo intel_frequency -g
> > cur: 200 MHz
> > min: 200 MHz
> > RP1: 200 MHz
> > max: 1200 MHz
> > 
> > $ sudo intel_frequency -geff
> > RP1: 200 MHz
> 
> I wouldn't expect this syntax to work, because generally single-letter
> options can be combined, so that "-geff" would be equivalent to "-g -e
> -f -f". I'd expect to have to write "-g eff" or "-g=eff".

This is a limitation of getsubopt() which is in the process of being removed
anyway, so I wouldn't worry about it.

> 
> > $ sudo intel_frequency --set min=300
> > $ sudo intel_frequency --get min
> > cur: 300 MHz
> > min: 300 MHz
> > RP1: 200 MHz
> > max: 1200 MHz
> 
> Surely if you specify "--get min" it should only print the "min" value,
> not all the others; and the same with "--get max" below. (However, I
> think you actually do need to show all values in these two examples to
> clarify the effects of the parameter-setting commands, so I'd change
> them to get rid of the parameter name).
> 
> Here, it isn't really clear what the difference between --custom and
> --set is supposed to be. Partly this is just down to the numbers in
> these specific examples, but also I think the examples don't agree with
> the code below.
> 
> > $ sudo intel_frequency --custom max=900
> > $ sudo intel_frequency --get max
> > cur: 300 MHz
> > min: 300 MHz
> > RP1: 200 MHz
> > max: 900 MHz
> 
> So from the code, I deduce that "--custom" lets you change either 'min'
> or 'max', but doesn't /necessarily/ change the current frequency, only
> if it becomes out-of-bounds.
> 
> OTOH "--set" is supposed to set both min *and* max, thus locking the
> frequency to a specific value. But the --set example above doesn't show
> that. Also, the "min=300" syntax would be illogical - you just need a
> number, and doesn't appear to be what the code actually expects.
> 

Looks like I messed up the comment, but it's going away shortly anyway. There is
a man page and help that describe the usage in more detail. I changed a bunch of
this midflight, and probably forgot to update the comments. Hasn't anyone ever
told you not to read comments before? If not, let me be the first :P

> Finally, I think the choice of command names (especially --set vs
> --custom) is confusing. I'd like to propose the following:
> 
> # Reading:
> 	--get		# get all
> 	--get namelist	# get specified
> 	-g [namelist]	# synonym for -g

--get is going to always get all. Initially I thought scripts could want to run
this app, but it's probably better if they just read the sysfs directly, if
the're scripting. Tim Gore already sent a patch which I've reviewed.

> 
> # Set one parameter:
> 	--set name=freq	# set the specified parameter (min or max)
> 			# may or may not affect 'cur'
> 	-s name=freq	# synonym
> 
> # Reset (all) parameters:
> 	--defaults	# Reset all r/w parameters to h/w defaults
> 	-d		# synonym
> 
> # Lock to specific frequency:
> 	--max		# Lock to (h/w defined) max
> 	-m		# synonym
> 	--min		# Lock to (h/w defined) min
> 	-i		# synonym
> 	--eff		# Lock to (h/w defined) RPe
> 	-e		# synonym
> 	--lock freq	# Lock to custom frequency
> 	-l freq		# synonym
> 
> [Aside]
> If the locking commands are implemented by setting both 'min' and 'max'
> to the same value, as appears to be the case in the code below, then
> defining "--max" and "--min to mean "lock to current value of max/min
> parameter (as I was originally going to) would result in the sequence of
> commands:
> 
> $ sudo intel_frequency --lock 900
> $ sudo intel_frequency --max
> 
> not having the expected effect - the second command would have no
> effect, because max would have been changed to 900 by the first. So it's
> better to for --min and --max to lock the frequency to the h/w default
> values.
> [/Aside]
> 
> Only one command may be given per invocation. (It could be meaningful to
> combine some permutations, but it would be complicated and/or confusing
> and involve extra (arbitrary) decisions, such as whether options are
> processed in command-line order or in fixed order, and hence whether or
> not "-d -g -m" is equivalent to "-m -g -d", etc. So KISS).
> 
> .Dave.
> 

I honestly don't care too much as long as we don't roll our own parsing. It made
sense to me to do it this way when I wrote it - note I didn't initially have
--custom at all, it was added by request from Jordan. Feel free to submit a
patch to change it to what you want. Opinions are like a$$holes, and everyone
has one.

Do realize again that the comments may not match the reality, and see Tim Gore's
patch before you change anything.

> > $ sudo intel_frequency --max
> > $ sudo intel_frequency -g
> > cur: 1200 MHz
> > min: 1200 MHz
> > RP1: 200 MHz
> > max: 1200 MHz
> > 
> > $ sudo intel_frequency -e
> > $ sudo intel_frequency -g
> > cur: 200 MHz
> > min: 200 MHz
> > RP1: 200 MHz
> > max: 200 MHz
> > 
> > $ sudo intel_frequency --max
> > $ sudo intel_frequency -g
> > cur: 1200 MHz
> > min: 1200 MHz
> > RP1: 200 MHz
> > max: 1200 MHz
> > 
> > $ sudo intel_frequency --min
> > $ sudo intel_frequency -g
> > cur: 200 MHz
> > min: 200 MHz
> > RP1: 200 MHz
> > max: 200 MHz
> > ---
> >  tools/Makefile.sources  |   1 +
> >  tools/intel_frequency.c | 363 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 364 insertions(+)
> >  create mode 100644 tools/intel_frequency.c
> > 
> > diff --git a/tools/Makefile.sources b/tools/Makefile.sources
> > index b85a6b8..2bea389 100644
> > --- a/tools/Makefile.sources
> > +++ b/tools/Makefile.sources
> > @@ -14,6 +14,7 @@ bin_PROGRAMS = 				\
> >  	intel_dump_decode 		\
> >  	intel_error_decode 		\
> >  	intel_forcewaked		\
> > +	intel_frequency			\
> >  	intel_framebuffer_dump 		\
> >  	intel_gpu_time 			\
> >  	intel_gpu_top 			\
> > diff --git a/tools/intel_frequency.c b/tools/intel_frequency.c
> > new file mode 100644
> > index 0000000..59f3814
> > --- /dev/null
> > +++ b/tools/intel_frequency.c
> > @@ -0,0 +1,363 @@
> > +/*
> > + * Copyright © 2015 Intel Corporation
> > + *
> > + * Permission is hereby granted, free of charge, to any person obtaining a
> > + * copy of this software and associated documentation files (the "Software"),
> > + * to deal in the Software without restriction, including without limitation
> > + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom the
> > + * Software is furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice (including the next
> > + * paragraph) shall be included in all copies or substantial portions of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> > + * DEALINGS IN THE SOFTWARE.
> > + *
> > + * Example:
> > + * Get all frequencies:
> > + * intel_frequency --get=cur,min,max,eff
> > + *
> > + * Same as above:
> > + * intel_frequency -g
> > + *
> > + * Get the efficient frequency:
> > + * intel_frequency -geff
> > + *
> > + * Lock the GPU frequency to 300MHz:
> > + * intel_frequency --set min=300
> > + *
> > + * Set the maximum frequency to 900MHz:
> > + * intel_frequency --custom max=900
> > + *
> > + * Lock the GPU frequency to its maximum frequency:
> > + * intel_frequency --max
> > + *
> > + * Lock the GPU frequency to its most efficient frequency:
> > + * intel_frequency -e
> > + *
> > + * Lock The GPU frequency to its minimum frequency:
> > + * intel_frequency --min
> > + *
> > + * Reset the GPU to hardware defaults
> > + * intel_frequency -d
> > + */
> > +
> > +#define _GNU_SOURCE
> > +#include <assert.h>
> > +#include <getopt.h>
> > +#include <stdio.h>
> > +#include <time.h>
> > +#include <unistd.h>
> > +
> > +#include "drmtest.h"
> > +#include "intel_chipset.h"
> > +
> > +static int device, devid;
> > +
> > +enum {
> > +	CUR=0,
> > +	MIN,
> > +	EFF,
> > +	MAX,
> > +	RP0,
> > +	RPn
> > +};
> > +
> > +struct freq_info {
> > +	const char *name;
> > +	const char *mode;
> > +	FILE *filp;
> > +	char *path;
> > +};
> > +
> > +static struct freq_info info[] = {
> > +	{ "cur", "r"  },
> > +	{ "min", "rb+" },
> > +	{ "RP1", "r" },
> > +	{ "max", "rb+" },
> > +	{ "RP0", "r" },
> > +	{ "RPn", "r" }
> > +};
> > +
> > +static char *
> > +get_sysfs_path(const char *which)
> > +{
> > +	static const char fmt[] = "/sys/class/drm/card%1d/gt_%3s_freq_mhz";
> > +	char *path;
> > +	int ret;
> > +
> > +#define STATIC_STRLEN(string) (sizeof(string) / sizeof(string [0]))
> > +	ret = asprintf(&path, fmt, device, which);
> > +	assert(ret == (STATIC_STRLEN(fmt) - 3));
> > +#undef STATIC_STRLEN
> > +
> > +	return path;
> > +}
> > +
> > +static void
> > +initialize_freq_info(struct freq_info *freq_info)
> > +{
> > +	if (freq_info->filp)
> > +		return;
> > +
> > +	freq_info->path = get_sysfs_path(freq_info->name);
> > +	assert(freq_info->path);
> > +	freq_info->filp = fopen(freq_info->path, freq_info->mode);
> > +	assert(freq_info->filp);
> > +}
> > +
> > +static void wait_freq_settle(void)
> > +{
> > +	struct timespec ts;
> > +
> > +	/* FIXME: Lazy sleep without check. */
> > +	ts.tv_sec = 0;
> > +	ts.tv_nsec = 20000;
> > +	clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL);
> > +}
> > +
> > +static void set_frequency(struct freq_info *freq_info, int val)
> > +{
> > +	initialize_freq_info(freq_info);
> > +	rewind(freq_info->filp);
> > +	assert(fprintf(freq_info->filp, "%d", val) > 0);
> > +
> > +	wait_freq_settle();
> > +}
> > +
> > +static int get_frequency(struct freq_info *freq_info)
> > +{
> > +	int val;
> > +
> > +	initialize_freq_info(freq_info);
> > +	rewind(freq_info->filp);
> > +	assert(fscanf(freq_info->filp, "%d", &val)==1);
> > +
> > +	return val;
> > +}
> > +
> > +static void
> > +usage(const char *prog)
> > +{
> > +	printf("Usage: %s [-e] [--min | --max] [-g (min|max|efficient)] [-s frequency_mhz]\n\n", prog);
> > +	printf("%s A program to manipulate Intel GPU frequencies.\n\n", prog);
> > +	printf("Options: \n");
> > +	printf("  -e		Lock frequency to the most efficient frequency\n");
> > +	printf("  -g, --get=    Get the frequency (optional arg: \"cur\"|\"min\"|\"max\"|\"eff\")\n");
> > +	printf("  -s, --set     Lock frequency to an absolute value (MHz)\n");
> > +	printf("  -c, --custom  Set a min, or max frequency \"min=X | max=Y\"\n");
> > +	printf("  -m  --max     Lock frequency to max frequency\n");
> > +	printf("  -i  --min     Lock frequency to min (never a good idea, DEBUG ONLY)\n");
> > +	printf("  -d  --defaults  Return the system to hardware defaults\n");
> > +	printf("Examples:\n");
> > +	printf("\tintel_frequency -gmin,cur Get the current and minimum frequency\n");
> > +	printf("\tintel_frequency -s 400    Lock frequency to 400Mhz\n");
> > +	printf("\tintel_frequency -c max=750 Set the max frequency to 750MHz\n");
> > +	exit(EXIT_FAILURE);
> > +}
> > +
> > +/* Returns read or write operation */
> > +static bool
> > +parse(int argc, char *argv[], bool *act_upon, int *new_freq)
> > +{
> > +	int c, tmp;
> > +	bool write = false;
> > +
> > +	char *token[] = {
> > +		(char *)info[CUR].name,
> > +		(char *)info[MIN].name,
> > +		(char *)"eff",
> > +		(char *)info[MAX].name
> > +	};
> > +
> > +	/* No args means -g" */
> > +	if (argc == 1) {
> > +		for (c = 0; c < ARRAY_SIZE(act_upon); c++)
> > +			act_upon[c] = true;
> > +		goto done;
> > +	}
> > +	while (1) {
> > +		int option_index = 0;
> > +		static struct option long_options[] = {
> > +			{ "get", optional_argument, NULL, 'g' },
> > +			{ "set", required_argument, NULL, 's' },
> > +			{ "custom", required_argument, NULL, 'c'},
> > +			{ "min", no_argument, NULL, 'i' },
> > +			{ "max", no_argument, NULL, 'm' },
> > +			{ "defaults", no_argument, NULL, 'd' },
> > +			{ "help", no_argument, NULL, 'h' },
> > +			{ NULL, 0, NULL, 0}
> > +		};
> > +
> > +		c = getopt_long(argc, argv, "eg::s:c:midh", long_options, &option_index);
> > +		if (c == -1)
> > +			break;
> > +
> > +		switch (c) {
> > +		case 'g':
> > +			if (write == true)
> > +				fprintf(stderr, "Read and write operations not support simultaneously.\n");
> > +
> > +			if (optarg) {
> > +				char *value, *subopts = optarg;
> > +				int x;
> > +				while (*subopts != '\0') {
> > +					x = getsubopt(&subopts, token, &value);
> > +					if (x == -1) {
> > +						fprintf(stderr, "Unrecognized option (%s)\n", value);
> > +						break;
> > +					} else
> > +						act_upon[x] = true;
> > +				}
> > +			} else {
> > +				int i;
> > +				for (i = 0; i < ARRAY_SIZE(act_upon); i++)
> > +					act_upon[i] = true;
> > +			}
> > +			break;
> > +		case 's':
> > +			if (!optarg)
> > +				usage(argv[0]);
> > +
> > +			if (write == true) {
> > +				fprintf(stderr, "Only one write may be specified at a time\n");
> > +				exit(EXIT_FAILURE);
> > +			}
> > +
> > +			write = true;
> > +			act_upon[MIN] = true;
> > +			act_upon[MAX] = true;
> > +			sscanf(optarg, "%d", &new_freq[MAX]);
> > +			new_freq[MIN] = new_freq[MAX];
> > +			break;
> > +		case 'c':
> > +			if (!optarg)
> > +				usage(argv[0]);
> > +
> > +			if (write == true) {
> > +				fprintf(stderr, "Only one write may be specified at a time\n");
> > +				exit(EXIT_FAILURE);
> > +			}
> > +
> > +			write = true;
> > +
> > +			if (!strncmp("min=", optarg, 4)) {
> > +				act_upon[MIN] = true;
> > +				sscanf(optarg+4, "%d", &new_freq[MIN]);
> > +			} else if (!strncmp("max=", optarg, 4)) {
> > +				act_upon[MAX] = true;
> > +				sscanf(optarg+4, "%d", &new_freq[MAX]);
> > +			} else {
> > +				fprintf(stderr, "Selected unmodifiable frequency\n");
> > +				exit(EXIT_FAILURE);
> > +			}
> > +			break;
> > +		case 'e': /* efficient */
> > +			if (IS_VALLEYVIEW(devid) || IS_CHERRYVIEW(devid)) {
> > +				/* the LP parts have special efficient frequencies */
> > +				fprintf(stderr,
> > +					"FIXME: Warning efficient frequency information is incorrect.\n");
> > +				exit(EXIT_FAILURE);
> > +			}
> > +			tmp = get_frequency(&info[EFF]);
> > +			new_freq[MIN] = tmp;
> > +			new_freq[MAX] = tmp;
> > +			act_upon[MIN] = true;
> > +			act_upon[MAX] = true;
> > +			write = true;
> > +			break;
> > +		case 'i': /* mIn */
> > +			tmp = get_frequency(&info[RPn]);
> > +			new_freq[MIN] = tmp;
> > +			new_freq[MAX] = tmp;
> > +			act_upon[MIN] = true;
> > +			act_upon[MAX] = true;
> > +			write = true;
> > +			break;
> > +		case 'm': /* max */
> > +			tmp = get_frequency(&info[RP0]);
> > +			new_freq[MIN] = tmp;
> > +			new_freq[MAX] = tmp;
> > +			act_upon[MIN] = true;
> > +			act_upon[MAX] = true;
> > +			write = true;
> > +			break;
> > +		case 'd': /* defaults */
> > +			new_freq[MIN] = get_frequency(&info[RPn]);
> > +			new_freq[MAX] = get_frequency(&info[RP0]);
> > +			act_upon[MIN] = true;
> > +			act_upon[MAX] = true;
> > +			write = true;
> > +			break;
> > +		case 'h':
> > +		default:
> > +			usage(argv[0]);
> > +		}
> > +	}
> > +
> > +done:
> > +	return write;
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +
> > +	bool write, fail, targets[MAX+1] = {false};
> > +	int i, try = 1, set_freq[MAX+1] = {0};
> > +
> > +	devid = intel_get_drm_devid(drm_open_any());
> > +	device = drm_get_card();
> > +
> > +	write = parse(argc, argv, targets, set_freq);
> > +	fail = write;
> > +
> > +	/* If we've previously locked the frequency, we need to make sure to set things
> > +	 * in the correct order, or else the operation will fail (ie. min = max = 200,
> > +	 * and we set min to 300, we fail because it would try to set min >
> > +	 * max). This can be accomplished be going either forward or reverse
> > +	 * through the loop. MIN is always before MAX.
> > +	 *
> > +	 * XXX: Since only min and max are at play, the super lazy way is to do this
> > +	 * 3 times and if we still fail after 3, it's for real.
> > +	 */
> > +again:
> > +	if (try > 2) {
> > +		fprintf(stderr, "Did not achieve desired freq.\n");
> > +		exit(EXIT_FAILURE);
> > +	}
> > +	for (i = 0; i < ARRAY_SIZE(targets); i++) {
> > +		if (targets[i] == false)
> > +			continue;
> > +
> > +		if (write) {
> > +			set_frequency(&info[i], set_freq[i]);
> > +			if (get_frequency(&info[i]) != set_freq[i])
> > +				fail = true;
> > +			else
> > +				fail = false;
> > +		} else {
> > +			printf("%s: %d MHz\n", info[i].name, get_frequency(&info[i]));
> > +		}
> > +	}
> > +
> > +	if (fail) {
> > +		try++;
> > +		goto again;
> > +	}
> > +
> > +	for (i = 0; i < ARRAY_SIZE(targets); i++) {
> > +		if (info[i].filp) {
> > +			fclose(info[i].filp);
> > +			free(info[i].path);
> > +		}
> > +	}
> > +
> > +	return EXIT_SUCCESS;
> > +}
> > 
> 
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