On 19. 7. 19. 오전 9:00, Dmitry Osipenko wrote: > В Thu, 18 Jul 2019 19:17:17 +0900 > Chanwoo Choi <[email protected]> пишет: > >> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote: >>> The current implementation is inaccurate and results in very >>> intensive interrupt activity, which neglects the whole idea of >>> polling offload to hardware. The reason of the shortcoming is that >>> watermarks are not set up correctly and this results in ACTMON >>> constantly asking to change freq and then these requests are >>> ignored. The end result of this patch is that there are few >>> hundreds of ACTMON's interrupts instead of tens thousands after few >>> minutes of a working devfreq, meanwhile the transitions activity >>> stays about the same and governor becomes more reactive. >>> >>> Since watermarks are set precisely correct now, the boosting logic >>> is changed a tad to accommodate the change. The "average sustain >>> coefficient" multiplier is gone now since there is no need to >>> compensate the improper watermarks and EMC frequency-bump happens >>> once boosting hits the upper watermark enough times, depending on >>> the per-device boosting threshold. >>> >>> Signed-off-by: Dmitry Osipenko <[email protected]> >>> --- >>> drivers/devfreq/tegra30-devfreq.c | 293 >>> +++++++++++++++++++++--------- 1 file changed, 209 insertions(+), >>> 84 deletions(-) >>> >>> diff --git a/drivers/devfreq/tegra30-devfreq.c >>> b/drivers/devfreq/tegra30-devfreq.c index >>> 4be7858c33bc..16f7e6cf3b99 100644 --- >>> a/drivers/devfreq/tegra30-devfreq.c +++ >>> b/drivers/devfreq/tegra30-devfreq.c @@ -47,6 +47,8 @@ >>> >>> #define ACTMON_DEV_INTR_CONSECUTIVE_UPPER >>> BIT(31) #define >>> ACTMON_DEV_INTR_CONSECUTIVE_LOWER BIT(30) >>> +#define >>> ACTMON_DEV_INTR_AVG_BELOW_WMARK >>> BIT(25) +#define >>> ACTMON_DEV_INTR_AVG_ABOVE_WMARK >>> BIT(24) #define >>> ACTMON_ABOVE_WMARK_WINDOW 1 #define >>> ACTMON_BELOW_WMARK_WINDOW 3 @@ -63,9 >>> +65,8 @@ >>> * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, >>> which >>> * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128 >>> */ >>> -#define ACTMON_AVERAGE_WINDOW_LOG2 6 >>> -#define ACTMON_SAMPLING_PERIOD >>> 12 /* ms */ -#define >>> ACTMON_DEFAULT_AVG_BAND 6 /* 1/10 >>> of % */ +#define >>> ACTMON_AVERAGE_WINDOW_LOG2 6 >>> +#define >>> ACTMON_SAMPLING_PERIOD 12 /* >>> ms */ #define >>> KHZ 1000 @@ >>> -142,9 +143,6 @@ struct tegra_devfreq_device { >>> * watermark breaches. >>> */ >>> unsigned long boost_freq; >>> - >>> - /* Optimal frequency calculated from the stats for this >>> device */ >>> - unsigned long target_freq; >>> }; >>> >>> struct tegra_devfreq { >>> @@ -156,7 +154,6 @@ struct tegra_devfreq { >>> >>> struct clk *emc_clock; >>> unsigned long max_freq; >>> - unsigned long cur_freq; >>> struct notifier_block rate_change_nb; >>> >>> struct tegra_devfreq_device >>> devices[ARRAY_SIZE(actmon_device_configs)]; @@ -205,42 +202,182 @@ >>> static unsigned long do_percent(unsigned long val, unsigned int >>> pct) return val * pct / 100; } >>> >>> +static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq >>> *tegra) +{ >>> + struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios; >>> + unsigned int cpu_freq = cpufreq_get(0); >>> + unsigned int i; >>> + >>> + for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, >>> ratio++) { >>> + if (cpu_freq >= ratio->cpu_freq) { >>> + if (ratio->emc_freq >= tegra->max_freq) >>> + return tegra->max_freq; >>> + else >>> + return ratio->emc_freq; >>> + } >>> + } >>> + >>> + return 0; >>> +} >>> + >>> +static unsigned long >>> +tegra_actmon_account_cpu_freq(struct tegra_devfreq *tegra, >>> + struct tegra_devfreq_device *dev, >>> + unsigned long target_freq) >>> +{ >>> + unsigned long static_cpu_emc_freq; >>> + >>> + if (dev->config->avg_dependency_threshold && >>> + dev->config->avg_dependency_threshold < >>> dev->avg_count) { >>> + static_cpu_emc_freq = >>> actmon_cpu_to_emc_rate(tegra); >>> + target_freq = max(target_freq, >>> static_cpu_emc_freq); >>> + } >>> + >>> + return target_freq; >>> +} >>> + >>> +static unsigned long tegra_actmon_lower_freq(struct tegra_devfreq >>> *tegra, >>> + unsigned long >>> target_freq) +{ >>> + unsigned long lower = target_freq; >>> + struct dev_pm_opp *opp; >>> + >>> + opp = >>> dev_pm_opp_find_freq_floor(tegra->devfreq->dev.parent, &lower); >>> + if (IS_ERR(opp)) >>> + lower = 0; >>> + else >>> + dev_pm_opp_put(opp); >>> + >>> + return lower; >>> +} >>> + >>> +static unsigned long tegra_actmon_upper_freq(struct tegra_devfreq >>> *tegra, >>> + unsigned long >>> target_freq) +{ >>> + unsigned long upper = target_freq + 1; >>> + struct dev_pm_opp *opp; >>> + >>> + opp = >>> dev_pm_opp_find_freq_ceil(tegra->devfreq->dev.parent, &upper); >>> + if (IS_ERR(opp)) >>> + upper = ULONG_MAX; >>> + else >>> + dev_pm_opp_put(opp); >>> + >>> + return upper; >>> +} >>> + >>> +static void tegra_actmon_get_lower_upper(struct tegra_devfreq >>> *tegra, >>> + struct >>> tegra_devfreq_device *dev, >>> + unsigned long target_freq, >>> + unsigned long *lower, >>> + unsigned long *upper) >>> +{ >>> + /* >>> + * Memory frequencies are guaranteed to have 1MHz >>> granularity >>> + * and thus we need this rounding down to get a proper >>> watermarks >>> + * range in a case where target_freq falls into a range of >>> + * next_possible_opp_freq - 1MHz. >>> + */ >>> + target_freq = round_down(target_freq, 1000000); >>> + >>> + /* watermarks are set at the borders of the corresponding >>> OPPs */ >>> + *lower = tegra_actmon_lower_freq(tegra, target_freq); >>> + *upper = tegra_actmon_upper_freq(tegra, target_freq); >>> + >>> + *lower /= KHZ; >>> + *upper /= KHZ; >>> + >>> + /* >>> + * The upper watermark should take into account CPU's >>> frequency >>> + * because cpu_to_emc_rate() may override the target_freq >>> with >>> + * a higher value and thus upper watermark need to be set >>> up >>> + * accordingly to avoid parasitic upper-events. >>> + */ >>> + *upper = tegra_actmon_account_cpu_freq(tegra, dev, *upper); >>> + >>> + *lower *= ACTMON_SAMPLING_PERIOD; >>> + *upper *= ACTMON_SAMPLING_PERIOD; >>> +} >>> + >>> static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq >>> *tegra, struct tegra_devfreq_device *dev) >>> { >>> - u32 avg = dev->avg_count; >>> - u32 avg_band_freq = tegra->max_freq * >>> ACTMON_DEFAULT_AVG_BAND / KHZ; >>> - u32 band = avg_band_freq * ACTMON_SAMPLING_PERIOD; >>> + unsigned long lower, upper, freq; >>> >>> - device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK); >>> + freq = dev->avg_count / ACTMON_SAMPLING_PERIOD * KHZ; >>> + tegra_actmon_get_lower_upper(tegra, dev, freq, &lower, >>> &upper); >>> - avg = max(dev->avg_count, band); >>> - device_writel(dev, avg - band, ACTMON_DEV_AVG_LOWER_WMARK); >>> + /* >>> + * We want to get interrupts when MCCPU client crosses the >>> + * dependency threshold in order to take into / out of >>> account >>> + * the CPU's freq. >>> + */ >>> + if (lower < dev->config->avg_dependency_threshold && >>> + upper > dev->config->avg_dependency_threshold) { >>> + if (dev->avg_count < >>> dev->config->avg_dependency_threshold) >>> + upper = >>> dev->config->avg_dependency_threshold; >>> + else >>> + lower = >>> dev->config->avg_dependency_threshold; >>> + } >>> + >>> + device_writel(dev, lower, ACTMON_DEV_AVG_LOWER_WMARK); >>> + device_writel(dev, upper, ACTMON_DEV_AVG_UPPER_WMARK); >>> } >>> >>> static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra, >>> - struct tegra_devfreq_device >>> *dev) >>> + struct tegra_devfreq_device >>> *dev, >>> + unsigned long freq) >>> { >>> - u32 val = tegra->cur_freq * ACTMON_SAMPLING_PERIOD; >>> + unsigned long lower, upper, delta; >>> + >>> + /* >>> + * Boosting logic kicks-in once lower / upper watermark is >>> hit. >>> + * The watermarks are based on the updated EMC rate and the >>> + * average activity. >>> + * >>> + * The higher watermark is set in accordance to the EMC >>> rate >>> + * because we want to set it to the highest mark here and >>> EMC rate >>> + * represents that mark. The consecutive-upper interrupts >>> are >>> + * always enabled and we don't want to receive them if >>> they won't >>> + * do anything useful, hence the upper watermark is capped >>> to maximum. >>> + * Note that the EMC rate is changed once boosting pushed >>> the rate >>> + * too high, in that case boosting-up will be stopped >>> because >>> + * upper watermark is much higher now and it is >>> *important* to >>> + * stop the unwanted interrupts. >>> + */ >>> + tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, >>> &upper); + >>> + delta = do_percent(upper - lower, >>> dev->config->boost_up_threshold); >>> + device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK); >>> >>> - device_writel(dev, do_percent(val, >>> dev->config->boost_up_threshold), >>> - ACTMON_DEV_UPPER_WMARK); >>> + /* >>> + * Meanwhile the lower mark is based on the average value >>> + * because it is the lowest possible consecutive-mark for >>> this >>> + * device. Once that mark is hit and boosting is stopped, >>> the >>> + * interrupt is disabled by ISR. >>> + */ >>> + freq = dev->avg_count / ACTMON_SAMPLING_PERIOD * KHZ; >>> + tegra_actmon_get_lower_upper(tegra, dev, freq, &lower, >>> &upper); >>> - device_writel(dev, do_percent(val, >>> dev->config->boost_down_threshold), >>> - ACTMON_DEV_LOWER_WMARK); >>> + delta = do_percent(upper - lower, >>> dev->config->boost_down_threshold); >>> + device_writel(dev, lower + delta, ACTMON_DEV_LOWER_WMARK); >>> } >>> >>> static void actmon_isr_device(struct tegra_devfreq *tegra, >>> struct tegra_devfreq_device *dev) >>> { >>> - u32 intr_status, dev_ctrl; >>> + u32 intr_status, dev_ctrl, avg_intr_mask; >>> >>> dev->avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT); >>> - tegra_devfreq_update_avg_wmark(tegra, dev); >>> - >>> intr_status = device_readl(dev, ACTMON_DEV_INTR_STATUS); >>> dev_ctrl = device_readl(dev, ACTMON_DEV_CTRL); >>> >>> + avg_intr_mask = ACTMON_DEV_INTR_AVG_BELOW_WMARK | >>> + ACTMON_DEV_INTR_AVG_ABOVE_WMARK; >>> + >>> + if (intr_status & avg_intr_mask) >>> + tegra_devfreq_update_avg_wmark(tegra, dev); >>> + >>> if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) { >>> /* >>> * new_boost = min(old_boost * up_coef + step, >>> max_freq) @@ -253,8 +390,6 @@ static void actmon_isr_device(struct >>> tegra_devfreq *tegra, >>> if (dev->boost_freq >= tegra->max_freq) >>> dev->boost_freq = tegra->max_freq; >>> - else >>> - dev_ctrl |= >>> ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN; } else if (intr_status >>> & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) { /* >>> * new_boost = old_boost * down_coef >>> @@ -263,63 +398,37 @@ static void actmon_isr_device(struct >>> tegra_devfreq *tegra, dev->boost_freq = do_percent(dev->boost_freq, >>> dev->config->boost_down_coeff); >>> >>> - dev_ctrl |= >>> ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN; - >>> if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> >>> 1)) dev->boost_freq = 0; >>> - else >>> - dev_ctrl |= >>> ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN; } >>> >>> - if (dev->config->avg_dependency_threshold) { >>> - if (dev->avg_count >= >>> dev->config->avg_dependency_threshold) >>> - dev_ctrl |= >>> ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN; >>> - else if (dev->boost_freq == 0) >>> - dev_ctrl &= >>> ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN; >>> + if (intr_status & avg_intr_mask) { >>> + /* >>> + * Once average watermark is hit, it means that >>> the memory >>> + * activity changed significantly and thus >>> boosting-up shall >>> + * be reset because EMC clock rate will be changed >>> and >>> + * boosting will restart in this case. >>> + */ >>> + dev->boost_freq = 0; >>> } >>> >>> - device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL); >>> + /* no boosting => no need for consecutive-down interrupt */ >>> + if (dev->boost_freq == 0) >>> + dev_ctrl &= >>> ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN; >>> + device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL); >>> device_writel(dev, ACTMON_INTR_STATUS_CLEAR, >>> ACTMON_DEV_INTR_STATUS); } >>> >>> -static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq >>> *tegra, >>> - unsigned long cpu_freq) >>> -{ >>> - unsigned int i; >>> - struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios; >>> - >>> - for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, >>> ratio++) { >>> - if (cpu_freq >= ratio->cpu_freq) { >>> - if (ratio->emc_freq >= tegra->max_freq) >>> - return tegra->max_freq; >>> - else >>> - return ratio->emc_freq; >>> - } >>> - } >>> - >>> - return 0; >>> -} >>> - >>> -static void actmon_update_target(struct tegra_devfreq *tegra, >>> - struct tegra_devfreq_device *dev) >>> +static unsigned long actmon_update_target(struct tegra_devfreq >>> *tegra, >>> + struct >>> tegra_devfreq_device *dev) { >>> - unsigned long cpu_freq = 0; >>> - unsigned long static_cpu_emc_freq = 0; >>> - unsigned int avg_sustain_coef; >>> - >>> - if (dev->config->avg_dependency_threshold) { >>> - cpu_freq = cpufreq_get(0); >>> - static_cpu_emc_freq = >>> actmon_cpu_to_emc_rate(tegra, cpu_freq); >>> - } >>> + unsigned long target_freq; >>> >>> - dev->target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD; >>> - avg_sustain_coef = 100 * 100 / >>> dev->config->boost_up_threshold; >>> - dev->target_freq = do_percent(dev->target_freq, >>> avg_sustain_coef); >>> - dev->target_freq += dev->boost_freq; >>> + target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD + >>> dev->boost_freq; >>> + target_freq = tegra_actmon_account_cpu_freq(tegra, dev, >>> target_freq); >>> - if (dev->avg_count >= >>> dev->config->avg_dependency_threshold) >>> - dev->target_freq = max(dev->target_freq, >>> static_cpu_emc_freq); >>> + return target_freq; >>> } >>> >>> static irqreturn_t actmon_thread_isr(int irq, void *data) >>> @@ -351,8 +460,8 @@ static int tegra_actmon_rate_notify_cb(struct >>> notifier_block *nb, unsigned long action, void *ptr) >>> { >>> struct clk_notifier_data *data = ptr; >>> - struct tegra_devfreq *tegra; >>> struct tegra_devfreq_device *dev; >>> + struct tegra_devfreq *tegra; >>> unsigned int i; >>> >>> if (action != POST_RATE_CHANGE) >>> @@ -360,12 +469,28 @@ static int tegra_actmon_rate_notify_cb(struct >>> notifier_block *nb, >>> tegra = container_of(nb, struct tegra_devfreq, >>> rate_change_nb); >>> - tegra->cur_freq = data->new_rate / KHZ; >>> - >>> + /* >>> + * EMC rate could change due to three reasons: >>> + * >>> + * 1. Average watermark hit >>> + * 2. Boosting overflow >>> + * 3. CPU freq change >>> + * >>> + * Once rate is changed, the consecutive watermarks need >>> to be >>> + * updated in order for boosting to work properly and to >>> avoid >>> + * unnecessary interrupts. Note that the consecutive range >>> is set for >>> + * all of devices using the same rate, hence if CPU is >>> doing much >>> + * less than the other memory clients, then its upper >>> watermark will >>> + * be very high in comparison to the actual activity >>> (lower watermark) >>> + * and thus unnecessary upper-interrupts will be >>> suppressed. >>> + * >>> + * The average watermarks also should be updated because >>> of 3. >>> + */ >>> for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) { >>> dev = &tegra->devices[i]; >>> >>> - tegra_devfreq_update_wmark(tegra, dev); >>> + tegra_devfreq_update_avg_wmark(tegra, dev); >>> + tegra_devfreq_update_wmark(tegra, dev, >>> data->new_rate); } >>> >>> return NOTIFY_OK; >>> @@ -374,15 +499,14 @@ static int tegra_actmon_rate_notify_cb(struct >>> notifier_block *nb, static void >>> tegra_actmon_configure_device(struct tegra_devfreq *tegra, struct >>> tegra_devfreq_device *dev) { >>> - u32 val = 0; >>> - >>> - dev->target_freq = tegra->cur_freq; >>> + u32 val = 0, target_freq; >>> >>> - dev->avg_count = tegra->cur_freq * ACTMON_SAMPLING_PERIOD; >>> + target_freq = clk_get_rate(tegra->emc_clock) / KHZ; >>> + dev->avg_count = target_freq * ACTMON_SAMPLING_PERIOD; >>> device_writel(dev, dev->avg_count, ACTMON_DEV_INIT_AVG); >>> >>> tegra_devfreq_update_avg_wmark(tegra, dev); >>> - tegra_devfreq_update_wmark(tegra, dev); >>> + tegra_devfreq_update_wmark(tegra, dev, target_freq); >>> >>> device_writel(dev, ACTMON_COUNT_WEIGHT, >>> ACTMON_DEV_COUNT_WEIGHT); device_writel(dev, >>> ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS); @@ -469,13 >>> +593,13 @@ static int tegra_devfreq_get_dev_status(struct device >>> *dev, struct tegra_devfreq_device *actmon_dev; unsigned long >>> cur_freq; >>> - cur_freq = READ_ONCE(tegra->cur_freq); >>> + cur_freq = clk_get_rate(tegra->emc_clock); >>> >>> /* To be used by the tegra governor */ >>> stat->private_data = tegra; >>> >>> /* The below are to be used by the other governors */ >>> - stat->current_frequency = cur_freq * KHZ; >>> + stat->current_frequency = cur_freq; >>> >>> actmon_dev = &tegra->devices[MCALL]; >>> >>> @@ -486,7 +610,7 @@ static int tegra_devfreq_get_dev_status(struct >>> device *dev, stat->busy_time *= 100 / BUS_SATURATION_RATIO; >>> >>> /* Number of cycles in a sampling period */ >>> - stat->total_time = ACTMON_SAMPLING_PERIOD * cur_freq; >>> + stat->total_time = cur_freq / KHZ * ACTMON_SAMPLING_PERIOD; >>> >>> stat->busy_time = min(stat->busy_time, stat->total_time); >>> >>> @@ -505,6 +629,7 @@ static int tegra_governor_get_target(struct >>> devfreq *devfreq, struct devfreq_dev_status *stat; >>> struct tegra_devfreq *tegra; >>> struct tegra_devfreq_device *dev; >>> + unsigned long dev_target_freq; >>> unsigned long target_freq = 0; >>> unsigned int i; >>> int err; >>> @@ -520,9 +645,9 @@ static int tegra_governor_get_target(struct >>> devfreq *devfreq, for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) { >>> dev = &tegra->devices[i]; >>> >>> - actmon_update_target(tegra, dev); >>> + dev_target_freq = actmon_update_target(tegra, dev); >>> >>> - target_freq = max(target_freq, dev->target_freq); >>> + target_freq = max(target_freq, dev_target_freq); >>> } >>> >>> *freq = target_freq * KHZ; >>> @@ -642,7 +767,6 @@ static int tegra_devfreq_probe(struct >>> platform_device *pdev) return rate; >>> } >>> >>> - tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ; >>> tegra->max_freq = rate / KHZ; >>> >>> for (i = 0; i < ARRAY_SIZE(actmon_device_configs); i++) { >>> @@ -671,7 +795,8 @@ static int tegra_devfreq_probe(struct >>> platform_device *pdev) platform_set_drvdata(pdev, tegra); >>> >>> tegra->rate_change_nb.notifier_call = >>> tegra_actmon_rate_notify_cb; >>> - err = clk_notifier_register(tegra->emc_clock, >>> &tegra->rate_change_nb); >>> + err = clk_notifier_register(tegra->emc_clock, >>> + &tegra->rate_change_nb); >>> if (err) { >>> dev_err(&pdev->dev, >>> "Failed to register rate change >>> notifier\n"); >> >> >> Maybe, it is possible to merge patch4/patch19/patch20 to one patch. > > All these three patches are completely separate changes, thus they > should be kept separate. >
I replied on patch19 why it is possible to merge patch5 and patch19. Please check my comment. -- Best Regards, Chanwoo Choi Samsung Electronics
