On Wed, Jun 14, 2023 at 03:39:59PM +0200, Konrad Dybcio wrote: > Currently we use predefined initial threshold values. This works, but > does not really scale well with more and more SoCs gaining bwmon support, > as the necessary kickoff values may differ between platforms due to memory > type and/or controller setup. > All of the data we need for that is already provided in the device tree, > anyway. > > Change the thresholds to: > * low = 0 (as we've been doing up until now) > * med = high = BW_MIN > > Throughput going below the med threshold nudges bwmon into signaling > that we should slow down (e.g. if we inherited too high bandwidth > from the bootloader). > > Throughput going above the high threshold nudges bwmon into signaling > that we should speed up so as not to choke the bus traffic due to > insufficient transfer rates. > > F_MIN is a perfect initial value for both of these cases - if we go > above it (and there's a 99.99% chance it'll happen at boot time), we > should definitely make the memory go faster, whereas if we go below it, > we should slow down, no matter what performance state we were at before > (it's only possible for them to be >= FMIN). > > This only changes the values programmed at probe time, as high and med > thresholds are updated at interrupt, also based on the OPP table from DT. > > Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx> Regards, Bjorn > --- > Changes in v2: > - Drop now-merged dependency > - Drop div4 for the med value > - Better explain the reasoning in the commit message > - Link to v1: https://lore.kernel.org/r/20230610-topic-bwmon_opp-v1-1-65125d7493fc@xxxxxxxxxx > --- > drivers/soc/qcom/icc-bwmon.c | 28 +++++++--------------------- > 1 file changed, 7 insertions(+), 21 deletions(-) > > diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c > index 40068a285913..8daf0eb03279 100644 > --- a/drivers/soc/qcom/icc-bwmon.c > +++ b/drivers/soc/qcom/icc-bwmon.c > @@ -165,9 +165,6 @@ enum bwmon_fields { > struct icc_bwmon_data { > unsigned int sample_ms; > unsigned int count_unit_kb; /* kbytes */ > - unsigned int default_highbw_kbps; > - unsigned int default_medbw_kbps; > - unsigned int default_lowbw_kbps; > u8 zone1_thres_count; > u8 zone3_thres_count; > unsigned int quirks; > @@ -564,20 +561,21 @@ static void bwmon_set_threshold(struct icc_bwmon *bwmon, > static void bwmon_start(struct icc_bwmon *bwmon) > { > const struct icc_bwmon_data *data = bwmon->data; > + u32 bw_low = 0; > int window; > > + /* No need to check for errors, as this must have succeeded before. */ > + dev_pm_opp_find_bw_ceil(bwmon->dev, &bw_low, 0); > + > bwmon_clear_counters(bwmon, true); > > window = mult_frac(bwmon->data->sample_ms, HW_TIMER_HZ, MSEC_PER_SEC); > /* Maximum sampling window: 0xffffff for v4 and 0xfffff for v5 */ > regmap_field_write(bwmon->regs[F_SAMPLE_WINDOW], window); > > - bwmon_set_threshold(bwmon, bwmon->regs[F_THRESHOLD_HIGH], > - data->default_highbw_kbps); > - bwmon_set_threshold(bwmon, bwmon->regs[F_THRESHOLD_MED], > - data->default_medbw_kbps); > - bwmon_set_threshold(bwmon, bwmon->regs[F_THRESHOLD_LOW], > - data->default_lowbw_kbps); > + bwmon_set_threshold(bwmon, bwmon->regs[F_THRESHOLD_HIGH], bw_low); > + bwmon_set_threshold(bwmon, bwmon->regs[F_THRESHOLD_MED], bw_low); > + bwmon_set_threshold(bwmon, bwmon->regs[F_THRESHOLD_LOW], 0); > > regmap_field_write(bwmon->regs[F_THRESHOLD_COUNT_ZONE0], > BWMON_THRESHOLD_COUNT_ZONE0_DEFAULT); > @@ -807,9 +805,6 @@ static int bwmon_remove(struct platform_device *pdev) > static const struct icc_bwmon_data msm8998_bwmon_data = { > .sample_ms = 4, > .count_unit_kb = 1024, > - .default_highbw_kbps = 4800 * 1024, /* 4.8 GBps */ > - .default_medbw_kbps = 512 * 1024, /* 512 MBps */ > - .default_lowbw_kbps = 0, > .zone1_thres_count = 16, > .zone3_thres_count = 1, > .quirks = BWMON_HAS_GLOBAL_IRQ, > @@ -822,9 +817,6 @@ static const struct icc_bwmon_data msm8998_bwmon_data = { > static const struct icc_bwmon_data sdm845_cpu_bwmon_data = { > .sample_ms = 4, > .count_unit_kb = 64, > - .default_highbw_kbps = 4800 * 1024, /* 4.8 GBps */ > - .default_medbw_kbps = 512 * 1024, /* 512 MBps */ > - .default_lowbw_kbps = 0, > .zone1_thres_count = 16, > .zone3_thres_count = 1, > .quirks = BWMON_HAS_GLOBAL_IRQ, > @@ -835,9 +827,6 @@ static const struct icc_bwmon_data sdm845_cpu_bwmon_data = { > static const struct icc_bwmon_data sdm845_llcc_bwmon_data = { > .sample_ms = 4, > .count_unit_kb = 1024, > - .default_highbw_kbps = 800 * 1024, /* 800 MBps */ > - .default_medbw_kbps = 256 * 1024, /* 256 MBps */ > - .default_lowbw_kbps = 0, > .zone1_thres_count = 16, > .zone3_thres_count = 1, > .regmap_fields = sdm845_llcc_bwmon_reg_fields, > @@ -847,9 +836,6 @@ static const struct icc_bwmon_data sdm845_llcc_bwmon_data = { > static const struct icc_bwmon_data sc7280_llcc_bwmon_data = { > .sample_ms = 4, > .count_unit_kb = 64, > - .default_highbw_kbps = 800 * 1024, /* 800 MBps */ > - .default_medbw_kbps = 256 * 1024, /* 256 MBps */ > - .default_lowbw_kbps = 0, > .zone1_thres_count = 16, > .zone3_thres_count = 1, > .quirks = BWMON_NEEDS_FORCE_CLEAR, > > --- > base-commit: b16049b21162bb649cdd8519642a35972b7910fe > change-id: 20230610-topic-bwmon_opp-f995bbdd18bd > > Best regards, > -- > Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> >
