src/intel/common/gen_l3_config.c - third_party/mesa - Git at Google

 /*
  * Copyright (c) 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.
  */

 #include <stdlib.h>
 #include <math.h>

 #include "util/macros.h"
 #include "main/macros.h"

 #include "gen_l3_config.h"

 /**
  * IVB/HSW validated L3 configurations.  The first entry will be used as
  * default by gen7_restore_default_l3_config(), otherwise the ordering is
  * unimportant.
  */
 static const struct gen_l3_config ivb_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 32,  0,  0, 32,  0,  0,  0 }},
    {{  0, 32,  0, 16, 16,  0,  0,  0 }},
    {{  0, 32,  0,  4,  0,  8,  4, 16 }},
    {{  0, 28,  0,  8,  0,  8,  4, 16 }},
    {{  0, 28,  0, 16,  0,  8,  4,  8 }},
    {{  0, 28,  0,  8,  0, 16,  4,  8 }},
    {{  0, 28,  0,  0,  0, 16,  4, 16 }},
    {{  0, 32,  0,  0,  0, 16,  0, 16 }},
    {{  0, 28,  0,  4, 32,  0,  0,  0 }},
    {{ 16, 16,  0, 16, 16,  0,  0,  0 }},
    {{ 16, 16,  0,  8,  0,  8,  8,  8 }},
    {{ 16, 16,  0,  4,  0,  8,  4, 16 }},
    {{ 16, 16,  0,  4,  0, 16,  4,  8 }},
    {{ 16, 16,  0,  0, 32,  0,  0,  0 }},
    {{ 0 }}
 };

 /**
  * VLV validated L3 configurations.  \sa ivb_l3_configs.
  */
 static const struct gen_l3_config vlv_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 64,  0,  0, 32,  0,  0,  0 }},
    {{  0, 80,  0,  0, 16,  0,  0,  0 }},
    {{  0, 80,  0,  8,  8,  0,  0,  0 }},
    {{  0, 64,  0, 16, 16,  0,  0,  0 }},
    {{  0, 60,  0,  4, 32,  0,  0,  0 }},
    {{ 32, 32,  0, 16, 16,  0,  0,  0 }},
    {{ 32, 40,  0,  8, 16,  0,  0,  0 }},
    {{ 32, 40,  0, 16,  8,  0,  0,  0 }},
    {{ 0 }}
 };

 /**
  * BDW validated L3 configurations.  \sa ivb_l3_configs.
  */
 static const struct gen_l3_config bdw_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 48, 48,  0,  0,  0,  0,  0 }},
    {{  0, 48,  0, 16, 32,  0,  0,  0 }},
    {{  0, 32,  0, 16, 48,  0,  0,  0 }},
    {{  0, 32,  0,  0, 64,  0,  0,  0 }},
    {{  0, 32, 64,  0,  0,  0,  0,  0 }},
    {{ 24, 16, 48,  0,  0,  0,  0,  0 }},
    {{ 24, 16,  0, 16, 32,  0,  0,  0 }},
    {{ 24, 16,  0, 32, 16,  0,  0,  0 }},
    {{ 0 }}
 };

 /**
  * CHV/SKL validated L3 configurations.  \sa ivb_l3_configs.
  */
 static const struct gen_l3_config chv_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 48, 48,  0,  0,  0,  0,  0 }},
    {{  0, 48,  0, 16, 32,  0,  0,  0 }},
    {{  0, 32,  0, 16, 48,  0,  0,  0 }},
    {{  0, 32,  0,  0, 64,  0,  0,  0 }},
    {{  0, 32, 64,  0,  0,  0,  0,  0 }},
    {{ 32, 16, 48,  0,  0,  0,  0,  0 }},
    {{ 32, 16,  0, 16, 32,  0,  0,  0 }},
    {{ 32, 16,  0, 32, 16,  0,  0,  0 }},
    {{ 0 }}
 };

 /**
  * BXT 2x6 validated L3 configurations.  \sa ivb_l3_configs.
  */
 static const struct gen_l3_config bxt_2x6_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 32, 48,  0,  0,  0,  0,  0 }},
    {{  0, 32,  0,  8, 40,  0,  0,  0 }},
    {{  0, 32,  0, 32, 16,  0,  0,  0 }},
    {{ 16, 16, 48,  0,  0,  0,  0,  0 }},
    {{ 16, 16,  0, 40,  8,  0,  0,  0 }},
    {{ 16, 16,  0, 16, 32,  0,  0,  0 }},
    {{ 0 }}
 };

 /**
  * CNL validated L3 configurations.  \sa ivb_l3_configs.
  */
 static const struct gen_l3_config cnl_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 64, 64,  0,  0,  0,  0,  0 }},
    {{  0, 64,  0, 16, 48,  0,  0,  0 }},
    {{  0, 48,  0, 16, 64,  0,  0,  0 }},
    {{  0, 32,  0,  0, 96,  0,  0,  0 }},
    {{  0, 32, 96,  0,  0,  0,  0,  0 }},
    {{  0, 32,  0, 16, 80,  0,  0,  0 }},
    {{ 32, 16, 80,  0,  0,  0,  0,  0 }},
    {{ 32, 16,  0, 64, 16,  0,  0,  0 }},
    {{ 32,  0, 96,  0,  0,  0,  0,  0 }},
    {{ 0 }}
 };

 /**
  * ICL validated L3 configurations.  \sa icl_l3_configs.
  * Zeroth entry in below table has been commented out intentionally
  * due to known issues with this configuration. Many other entries
  * suggested by h/w specification aren't added here because they
  * do under allocation of L3 cache with below partitioning.
  */
 static const struct gen_l3_config icl_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    /*{{  0, 16, 80,  0,  0,  0,  0,  0 }},*/
    {{  0, 32, 64,  0,  0,  0,  0,  0 }},
    {{  0 }}
 };

 /**
  * TGL validated L3 configurations.  \sa tgl_l3_configs.
  */
 static const struct gen_l3_config tgl_l3_configs[] = {
    /* SLM URB ALL DC  RO  IS   C   T */
    {{  0, 32,  88,  0,  0,  0,  0,  0 }},
    {{  0, 16, 104,  0,  0,  0,  0,  0 }},
    {{  0 }}
 };

 /**
  * Return a zero-terminated array of validated L3 configurations for the
  * specified device.
  */
 static const struct gen_l3_config *
 get_l3_configs(const struct gen_device_info *devinfo)
 {
    switch (devinfo->gen) {
    case 7:
       return (devinfo->is_baytrail ? vlv_l3_configs : ivb_l3_configs);

    case 8:
       return (devinfo->is_cherryview ? chv_l3_configs : bdw_l3_configs);

    case 9:
       if (devinfo->l3_banks == 1)
          return bxt_2x6_l3_configs;
       return chv_l3_configs;

    case 10:
       return cnl_l3_configs;

    case 11:
       return icl_l3_configs;

    case 12:
       return tgl_l3_configs;

    default:
       unreachable("Not implemented");
    }
 }

 /**
  * L1-normalize a vector of L3 partition weights.
  */
 static struct gen_l3_weights
 norm_l3_weights(struct gen_l3_weights w)
 {
    float sz = 0;

    for (unsigned i = 0; i < GEN_NUM_L3P; i++)
       sz += w.w[i];

    for (unsigned i = 0; i < GEN_NUM_L3P; i++)
       w.w[i] /= sz;

    return w;
 }

 /**
  * Get the relative partition weights of the specified L3 configuration.
  */
 struct gen_l3_weights
 gen_get_l3_config_weights(const struct gen_l3_config *cfg)
 {
    if (cfg) {
       struct gen_l3_weights w;

       for (unsigned i = 0; i < GEN_NUM_L3P; i++)
          w.w[i] = cfg->n[i];

       return norm_l3_weights(w);
    } else {
       const struct gen_l3_weights w = { { 0 } };
       return w;
    }
 }

 /**
  * Distance between two L3 configurations represented as vectors of weights.
  * Usually just the L1 metric except when the two configurations are
  * considered incompatible in which case the distance will be infinite.  Note
  * that the compatibility condition is asymmetric -- They will be considered
  * incompatible whenever the reference configuration \p w0 requires SLM, DC,
  * or URB but \p w1 doesn't provide it.
  */
 float
 gen_diff_l3_weights(struct gen_l3_weights w0, struct gen_l3_weights w1)
 {
    if ((w0.w[GEN_L3P_SLM] && !w1.w[GEN_L3P_SLM]) ||
        (w0.w[GEN_L3P_DC] && !w1.w[GEN_L3P_DC] && !w1.w[GEN_L3P_ALL]) ||
        (w0.w[GEN_L3P_URB] && !w1.w[GEN_L3P_URB])) {
       return HUGE_VALF;

    } else {
       float dw = 0;

       for (unsigned i = 0; i < GEN_NUM_L3P; i++)
          dw += fabs(w0.w[i] - w1.w[i]);

       return dw;
    }
 }

 /**
  * Return a reasonable default L3 configuration for the specified device based
  * on whether SLM and DC are required.  In the non-SLM non-DC case the result
  * is intended to approximately resemble the hardware defaults.
  */
 struct gen_l3_weights
 gen_get_default_l3_weights(const struct gen_device_info *devinfo,
                            bool needs_dc, bool needs_slm)
 {
    struct gen_l3_weights w = {{ 0 }};

    w.w[GEN_L3P_SLM] = devinfo->gen < 11 && needs_slm;
    w.w[GEN_L3P_URB] = 1.0;

    if (devinfo->gen >= 8) {
       w.w[GEN_L3P_ALL] = 1.0;
    } else {
       w.w[GEN_L3P_DC] = needs_dc ? 0.1 : 0;
       w.w[GEN_L3P_RO] = devinfo->is_baytrail ? 0.5 : 1.0;
    }

    return norm_l3_weights(w);
 }

 /**
  * Get the default L3 configuration
  */
 const struct gen_l3_config *
 gen_get_default_l3_config(const struct gen_device_info *devinfo)
 {
    /* For efficiency assume that the first entry of the array matches the
     * default configuration.
     */
    const struct gen_l3_config *const cfg = get_l3_configs(devinfo);
    assert(cfg == gen_get_l3_config(devinfo,
                     gen_get_default_l3_weights(devinfo, false, false)));
    return cfg;
 }

 /**
  * Return the closest validated L3 configuration for the specified device and
  * weight vector.
  */
 const struct gen_l3_config *
 gen_get_l3_config(const struct gen_device_info *devinfo,
                   struct gen_l3_weights w0)
 {
    const struct gen_l3_config *const cfgs = get_l3_configs(devinfo);
    const struct gen_l3_config *cfg_best = NULL;
    float dw_best = HUGE_VALF;

    for (const struct gen_l3_config *cfg = cfgs; cfg->n[GEN_L3P_URB]; cfg++) {
       const float dw = gen_diff_l3_weights(w0, gen_get_l3_config_weights(cfg));

       if (dw < dw_best) {
          cfg_best = cfg;
          dw_best = dw;
       }
    }

    return cfg_best;
 }

 /**
  * Return the size of an L3 way in KB.
  */
 static unsigned
 get_l3_way_size(const struct gen_device_info *devinfo)
 {
    const unsigned way_size_per_bank =
       (devinfo->gen >= 9 && devinfo->l3_banks == 1) || devinfo->gen == 11 ?
       4 : 2;

    assert(devinfo->l3_banks);
    return way_size_per_bank * devinfo->l3_banks;
 }

 /**
  * Return the unit brw_context::urb::size is expressed in, in KB.  \sa
  * gen_device_info::urb::size.
  */
 static unsigned
 get_urb_size_scale(const struct gen_device_info *devinfo)
 {
    return (devinfo->gen >= 8 ? devinfo->num_slices : 1);
 }

 unsigned
 gen_get_l3_config_urb_size(const struct gen_device_info *devinfo,
                            const struct gen_l3_config *cfg)
 {
    /* From the SKL "L3 Allocation and Programming" documentation:
     *
     * "URB is limited to 1008KB due to programming restrictions.  This is not
     * a restriction of the L3 implementation, but of the FF and other clients.
     * Therefore, in a GT4 implementation it is possible for the programmed
     * allocation of the L3 data array to provide 3*384KB=1152KB for URB, but
     * only 1008KB of this will be used."
     */
    const unsigned max = (devinfo->gen == 9 ? 1008 : ~0);
    return MIN2(max, cfg->n[GEN_L3P_URB] * get_l3_way_size(devinfo)) /
           get_urb_size_scale(devinfo);
 }

 /**
  * Print out the specified L3 configuration.
  */
 void
 gen_dump_l3_config(const struct gen_l3_config *cfg, FILE *fp)
 {
    fprintf(stderr, "SLM=%d URB=%d ALL=%d DC=%d RO=%d IS=%d C=%d T=%d\n",
            cfg->n[GEN_L3P_SLM], cfg->n[GEN_L3P_URB], cfg->n[GEN_L3P_ALL],
            cfg->n[GEN_L3P_DC], cfg->n[GEN_L3P_RO],
            cfg->n[GEN_L3P_IS], cfg->n[GEN_L3P_C], cfg->n[GEN_L3P_T]);
 }
	/*
	* Copyright (c) 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.
	*/

	#include <stdlib.h>
	#include <math.h>

	#include "util/macros.h"
	#include "main/macros.h"

	#include "gen_l3_config.h"

	/**
	* IVB/HSW validated L3 configurations. The first entry will be used as
	* default by gen7_restore_default_l3_config(), otherwise the ordering is
	* unimportant.
	*/
	static const struct gen_l3_config ivb_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 32, 0, 0, 32, 0, 0, 0 }},
	{{ 0, 32, 0, 16, 16, 0, 0, 0 }},
	{{ 0, 32, 0, 4, 0, 8, 4, 16 }},
	{{ 0, 28, 0, 8, 0, 8, 4, 16 }},
	{{ 0, 28, 0, 16, 0, 8, 4, 8 }},
	{{ 0, 28, 0, 8, 0, 16, 4, 8 }},
	{{ 0, 28, 0, 0, 0, 16, 4, 16 }},
	{{ 0, 32, 0, 0, 0, 16, 0, 16 }},
	{{ 0, 28, 0, 4, 32, 0, 0, 0 }},
	{{ 16, 16, 0, 16, 16, 0, 0, 0 }},
	{{ 16, 16, 0, 8, 0, 8, 8, 8 }},
	{{ 16, 16, 0, 4, 0, 8, 4, 16 }},
	{{ 16, 16, 0, 4, 0, 16, 4, 8 }},
	{{ 16, 16, 0, 0, 32, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* VLV validated L3 configurations. \sa ivb_l3_configs.
	*/
	static const struct gen_l3_config vlv_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 64, 0, 0, 32, 0, 0, 0 }},
	{{ 0, 80, 0, 0, 16, 0, 0, 0 }},
	{{ 0, 80, 0, 8, 8, 0, 0, 0 }},
	{{ 0, 64, 0, 16, 16, 0, 0, 0 }},
	{{ 0, 60, 0, 4, 32, 0, 0, 0 }},
	{{ 32, 32, 0, 16, 16, 0, 0, 0 }},
	{{ 32, 40, 0, 8, 16, 0, 0, 0 }},
	{{ 32, 40, 0, 16, 8, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* BDW validated L3 configurations. \sa ivb_l3_configs.
	*/
	static const struct gen_l3_config bdw_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 48, 48, 0, 0, 0, 0, 0 }},
	{{ 0, 48, 0, 16, 32, 0, 0, 0 }},
	{{ 0, 32, 0, 16, 48, 0, 0, 0 }},
	{{ 0, 32, 0, 0, 64, 0, 0, 0 }},
	{{ 0, 32, 64, 0, 0, 0, 0, 0 }},
	{{ 24, 16, 48, 0, 0, 0, 0, 0 }},
	{{ 24, 16, 0, 16, 32, 0, 0, 0 }},
	{{ 24, 16, 0, 32, 16, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* CHV/SKL validated L3 configurations. \sa ivb_l3_configs.
	*/
	static const struct gen_l3_config chv_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 48, 48, 0, 0, 0, 0, 0 }},
	{{ 0, 48, 0, 16, 32, 0, 0, 0 }},
	{{ 0, 32, 0, 16, 48, 0, 0, 0 }},
	{{ 0, 32, 0, 0, 64, 0, 0, 0 }},
	{{ 0, 32, 64, 0, 0, 0, 0, 0 }},
	{{ 32, 16, 48, 0, 0, 0, 0, 0 }},
	{{ 32, 16, 0, 16, 32, 0, 0, 0 }},
	{{ 32, 16, 0, 32, 16, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* BXT 2x6 validated L3 configurations. \sa ivb_l3_configs.
	*/
	static const struct gen_l3_config bxt_2x6_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 32, 48, 0, 0, 0, 0, 0 }},
	{{ 0, 32, 0, 8, 40, 0, 0, 0 }},
	{{ 0, 32, 0, 32, 16, 0, 0, 0 }},
	{{ 16, 16, 48, 0, 0, 0, 0, 0 }},
	{{ 16, 16, 0, 40, 8, 0, 0, 0 }},
	{{ 16, 16, 0, 16, 32, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* CNL validated L3 configurations. \sa ivb_l3_configs.
	*/
	static const struct gen_l3_config cnl_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 64, 64, 0, 0, 0, 0, 0 }},
	{{ 0, 64, 0, 16, 48, 0, 0, 0 }},
	{{ 0, 48, 0, 16, 64, 0, 0, 0 }},
	{{ 0, 32, 0, 0, 96, 0, 0, 0 }},
	{{ 0, 32, 96, 0, 0, 0, 0, 0 }},
	{{ 0, 32, 0, 16, 80, 0, 0, 0 }},
	{{ 32, 16, 80, 0, 0, 0, 0, 0 }},
	{{ 32, 16, 0, 64, 16, 0, 0, 0 }},
	{{ 32, 0, 96, 0, 0, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* ICL validated L3 configurations. \sa icl_l3_configs.
	* Zeroth entry in below table has been commented out intentionally
	* due to known issues with this configuration. Many other entries
	* suggested by h/w specification aren't added here because they
	* do under allocation of L3 cache with below partitioning.
	*/
	static const struct gen_l3_config icl_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	/{{ 0, 16, 80, 0, 0, 0, 0, 0 }},/
	{{ 0, 32, 64, 0, 0, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* TGL validated L3 configurations. \sa tgl_l3_configs.
	*/
	static const struct gen_l3_config tgl_l3_configs[] = {
	/* SLM URB ALL DC RO IS C T */
	{{ 0, 32, 88, 0, 0, 0, 0, 0 }},
	{{ 0, 16, 104, 0, 0, 0, 0, 0 }},
	{{ 0 }}
	};

	/**
	* Return a zero-terminated array of validated L3 configurations for the
	* specified device.
	*/
	static const struct gen_l3_config *
	get_l3_configs(const struct gen_device_info *devinfo)
	{
	switch (devinfo->gen) {
	case 7:
	return (devinfo->is_baytrail ? vlv_l3_configs : ivb_l3_configs);

	case 8:
	return (devinfo->is_cherryview ? chv_l3_configs : bdw_l3_configs);

	case 9:
	if (devinfo->l3_banks == 1)
	return bxt_2x6_l3_configs;
	return chv_l3_configs;

	case 10:
	return cnl_l3_configs;

	case 11:
	return icl_l3_configs;

	case 12:
	return tgl_l3_configs;

	default:
	unreachable("Not implemented");
	}
	}

	/**
	* L1-normalize a vector of L3 partition weights.
	*/
	static struct gen_l3_weights
	norm_l3_weights(struct gen_l3_weights w)
	{
	float sz = 0;

	for (unsigned i = 0; i < GEN_NUM_L3P; i++)
	sz += w.w[i];

	for (unsigned i = 0; i < GEN_NUM_L3P; i++)
	w.w[i] /= sz;

	return w;
	}

	/**
	* Get the relative partition weights of the specified L3 configuration.
	*/
	struct gen_l3_weights
	gen_get_l3_config_weights(const struct gen_l3_config *cfg)
	{
	if (cfg) {
	struct gen_l3_weights w;

	for (unsigned i = 0; i < GEN_NUM_L3P; i++)
	w.w[i] = cfg->n[i];

	return norm_l3_weights(w);
	} else {
	const struct gen_l3_weights w = { { 0 } };
	return w;
	}
	}

	/**
	* Distance between two L3 configurations represented as vectors of weights.
	* Usually just the L1 metric except when the two configurations are
	* considered incompatible in which case the distance will be infinite. Note
	* that the compatibility condition is asymmetric -- They will be considered
	* incompatible whenever the reference configuration \p w0 requires SLM, DC,
	* or URB but \p w1 doesn't provide it.
	*/
	float
	gen_diff_l3_weights(struct gen_l3_weights w0, struct gen_l3_weights w1)
	{
	if ((w0.w[GEN_L3P_SLM] && !w1.w[GEN_L3P_SLM]) \|\|
	(w0.w[GEN_L3P_DC] && !w1.w[GEN_L3P_DC] && !w1.w[GEN_L3P_ALL]) \|\|
	(w0.w[GEN_L3P_URB] && !w1.w[GEN_L3P_URB])) {
	return HUGE_VALF;

	} else {
	float dw = 0;

	for (unsigned i = 0; i < GEN_NUM_L3P; i++)
	dw += fabs(w0.w[i] - w1.w[i]);

	return dw;
	}
	}

	/**
	* Return a reasonable default L3 configuration for the specified device based
	* on whether SLM and DC are required. In the non-SLM non-DC case the result
	* is intended to approximately resemble the hardware defaults.
	*/
	struct gen_l3_weights
	gen_get_default_l3_weights(const struct gen_device_info *devinfo,
	bool needs_dc, bool needs_slm)
	{
	struct gen_l3_weights w = {{ 0 }};

	w.w[GEN_L3P_SLM] = devinfo->gen < 11 && needs_slm;
	w.w[GEN_L3P_URB] = 1.0;

	if (devinfo->gen >= 8) {
	w.w[GEN_L3P_ALL] = 1.0;
	} else {
	w.w[GEN_L3P_DC] = needs_dc ? 0.1 : 0;
	w.w[GEN_L3P_RO] = devinfo->is_baytrail ? 0.5 : 1.0;
	}

	return norm_l3_weights(w);
	}

	/**
	* Get the default L3 configuration
	*/
	const struct gen_l3_config *
	gen_get_default_l3_config(const struct gen_device_info *devinfo)
	{
	/* For efficiency assume that the first entry of the array matches the
	* default configuration.
	*/
	const struct gen_l3_config *const cfg = get_l3_configs(devinfo);
	assert(cfg == gen_get_l3_config(devinfo,
	gen_get_default_l3_weights(devinfo, false, false)));
	return cfg;
	}

	/**
	* Return the closest validated L3 configuration for the specified device and
	* weight vector.
	*/
	const struct gen_l3_config *
	gen_get_l3_config(const struct gen_device_info *devinfo,
	struct gen_l3_weights w0)
	{
	const struct gen_l3_config *const cfgs = get_l3_configs(devinfo);
	const struct gen_l3_config *cfg_best = NULL;
	float dw_best = HUGE_VALF;

	for (const struct gen_l3_config *cfg = cfgs; cfg->n[GEN_L3P_URB]; cfg++) {
	const float dw = gen_diff_l3_weights(w0, gen_get_l3_config_weights(cfg));

	if (dw < dw_best) {
	cfg_best = cfg;
	dw_best = dw;
	}
	}

	return cfg_best;
	}

	/**
	* Return the size of an L3 way in KB.
	*/
	static unsigned
	get_l3_way_size(const struct gen_device_info *devinfo)
	{
	const unsigned way_size_per_bank =
	(devinfo->gen >= 9 && devinfo->l3_banks == 1) \|\| devinfo->gen == 11 ?
	4 : 2;

	assert(devinfo->l3_banks);
	return way_size_per_bank * devinfo->l3_banks;
	}

	/**
	* Return the unit brw_context::urb::size is expressed in, in KB. \sa
	* gen_device_info::urb::size.
	*/
	static unsigned
	get_urb_size_scale(const struct gen_device_info *devinfo)
	{
	return (devinfo->gen >= 8 ? devinfo->num_slices : 1);
	}

	unsigned
	gen_get_l3_config_urb_size(const struct gen_device_info *devinfo,
	const struct gen_l3_config *cfg)
	{
	/* From the SKL "L3 Allocation and Programming" documentation:
	*
	* "URB is limited to 1008KB due to programming restrictions. This is not
	* a restriction of the L3 implementation, but of the FF and other clients.
	* Therefore, in a GT4 implementation it is possible for the programmed
	* allocation of the L3 data array to provide 3*384KB=1152KB for URB, but
	* only 1008KB of this will be used."
	*/
	const unsigned max = (devinfo->gen == 9 ? 1008 : ~0);
	return MIN2(max, cfg->n[GEN_L3P_URB] * get_l3_way_size(devinfo)) /
	get_urb_size_scale(devinfo);
	}

	/**
	* Print out the specified L3 configuration.
	*/
	void
	gen_dump_l3_config(const struct gen_l3_config cfg, FILE fp)
	{
	fprintf(stderr, "SLM=%d URB=%d ALL=%d DC=%d RO=%d IS=%d C=%d T=%d\n",
	cfg->n[GEN_L3P_SLM], cfg->n[GEN_L3P_URB], cfg->n[GEN_L3P_ALL],
	cfg->n[GEN_L3P_DC], cfg->n[GEN_L3P_RO],
	cfg->n[GEN_L3P_IS], cfg->n[GEN_L3P_C], cfg->n[GEN_L3P_T]);
	}