From: Konrad Dybcio <konrad.dybcio@linaro.org>
To: Stephan Gerhold <stephan@gerhold.net>
Cc: Andy Gross <agross@kernel.org>,
Bjorn Andersson <andersson@kernel.org>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>,
Georgi Djakov <djakov@kernel.org>, Leo Yan <leo.yan@linaro.org>,
Evan Green <evgreen@chromium.org>,
Marijn Suijten <marijn.suijten@somainline.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-clk@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH v2 22/22] interconnect: qcom: icc-rpm: Fix bandwidth calculations
Date: Sat, 10 Jun 2023 21:09:18 +0200 [thread overview]
Message-ID: <5362844c-253c-b624-c8f0-81a06a891dbd@linaro.org> (raw)
In-Reply-To: <ZITJw05MYgCjzLFx@gerhold.net>
On 10.06.2023 21:06, Stephan Gerhold wrote:
> On Fri, Jun 09, 2023 at 10:19:27PM +0200, Konrad Dybcio wrote:
>> Up until now, we've been aggregating the bandwidth values and only
>> dividing them by the bus width of the source node. This was completely
>> wrong, as different nodes on a given path may (and usually do) have
>> varying bus widths. That in turn, resulted in the calculated clock rates
>> being completely bogus - usually they ended up being much higher, as
>> NoC_A<->NoC_B links are very wide.
>>
>> Since we're not using the aggregate bandwidth value for anything other
>> than clock rate calculations, remodel qcom_icc_bus_aggregate() to
>> calculate the per-context clock rate for a given provider, taking into
>> account the bus width of every individual node.
>>
>> Fixes: 30c8fa3ec61a ("interconnect: qcom: Add MSM8916 interconnect provider driver")
>> Reported-by: Stephan Gerhold <stephan@gerhold.net>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
>> ---
>> drivers/interconnect/qcom/icc-rpm.c | 59 ++++++++++++-------------------------
>> 1 file changed, 19 insertions(+), 40 deletions(-)
>>
>> diff --git a/drivers/interconnect/qcom/icc-rpm.c b/drivers/interconnect/qcom/icc-rpm.c
>> index 1508233632f6..d177a76abe2a 100644
>> --- a/drivers/interconnect/qcom/icc-rpm.c
>> +++ b/drivers/interconnect/qcom/icc-rpm.c
>> @@ -293,58 +293,44 @@ static int qcom_icc_bw_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
>> }
>>
>> /**
>> - * qcom_icc_bus_aggregate - aggregate bandwidth by traversing all nodes
>> + * qcom_icc_bus_aggregate - calculate bus clock rates by traversing all nodes
>> * @provider: generic interconnect provider
>> - * @agg_avg: an array for aggregated average bandwidth of buckets
>> - * @agg_peak: an array for aggregated peak bandwidth of buckets
>> - * @max_agg_avg: pointer to max value of aggregated average bandwidth
>> + * @agg_clk_rate: array containing the aggregated clock rates in kHz
>> */
>> -static void qcom_icc_bus_aggregate(struct icc_provider *provider,
>> - u64 *agg_avg, u64 *agg_peak,
>> - u64 *max_agg_avg)
>> +static void qcom_icc_bus_aggregate(struct icc_provider *provider, u64 *agg_clk_rate)
>> {
>> - struct icc_node *node;
>> + u64 agg_avg_rate, agg_rate;
>> struct qcom_icc_node *qn;
>> - u64 sum_avg[QCOM_SMD_RPM_STATE_NUM];
>> + struct icc_node *node;
>> int i;
>>
>> - /* Initialise aggregate values */
>> - for (i = 0; i < QCOM_SMD_RPM_STATE_NUM; i++) {
>> - agg_avg[i] = 0;
>> - agg_peak[i] = 0;
>> - }
>> -
>> - *max_agg_avg = 0;
>> -
>> /*
>> - * Iterate nodes on the interconnect and aggregate bandwidth
>> - * requests for every bucket.
>> + * Iterate nodes on the provider, aggregate bandwidth requests for
>> + * every bucket and convert them into bus clock rates.
>> */
>> list_for_each_entry(node, &provider->nodes, node_list) {
>> qn = node->data;
>> for (i = 0; i < QCOM_SMD_RPM_STATE_NUM; i++) {
>> if (qn->channels)
>> - sum_avg[i] = div_u64(qn->sum_avg[i], qn->channels);
>> + agg_avg_rate = div_u64(qn->sum_avg[i], qn->channels);
>> else
>> - sum_avg[i] = qn->sum_avg[i];
>> - agg_avg[i] += sum_avg[i];
>> - agg_peak[i] = max_t(u64, agg_peak[i], qn->max_peak[i]);
>> + agg_avg_rate = qn->sum_avg[i];
>> +
>> + agg_rate = max_t(u64, agg_avg_rate, qn->max_peak[i]);
>> + do_div(agg_rate, qn->buswidth);
>> +
>> + agg_clk_rate[i] = max_t(u64, agg_clk_rate[i], agg_rate);
>> }
>> }
>> -
>> - /* Find maximum values across all buckets */
>> - for (i = 0; i < QCOM_SMD_RPM_STATE_NUM; i++)
>> - *max_agg_avg = max_t(u64, *max_agg_avg, agg_avg[i]);
>> }
>>
>> static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
>> {
>> - struct qcom_icc_provider *qp;
>> struct qcom_icc_node *src_qn = NULL, *dst_qn = NULL;
>> + u64 agg_clk_rate[QCOM_SMD_RPM_STATE_NUM] = { 0 };
>> struct icc_provider *provider;
>> + struct qcom_icc_provider *qp;
>> u64 active_rate, sleep_rate;
>> - u64 agg_avg[QCOM_SMD_RPM_STATE_NUM], agg_peak[QCOM_SMD_RPM_STATE_NUM];
>> - u64 max_agg_avg;
>> int ret;
>>
>> src_qn = src->data;
>> @@ -353,7 +339,9 @@ static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
>> provider = src->provider;
>> qp = to_qcom_provider(provider);
>>
>> - qcom_icc_bus_aggregate(provider, agg_avg, agg_peak, &max_agg_avg);
>> + qcom_icc_bus_aggregate(provider, agg_clk_rate);
>> + active_rate = agg_clk_rate[QCOM_SMD_RPM_ACTIVE_STATE];
>> + sleep_rate = agg_clk_rate[QCOM_SMD_RPM_SLEEP_STATE];
>>
>> ret = qcom_icc_rpm_set(src_qn, src_qn->sum_avg);
>> if (ret)
>> @@ -369,15 +357,6 @@ static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
>> if (!qp->bus_clk_desc && !qp->bus_clk)
>> return 0;
>>
>> - /* Intentionally keep the rates in kHz as that's what RPM accepts */
>
> I kind of liked this comment because otherwise it's not obvious why
> you're not converting from "ICC units" anywhere.
I figured the kerneldoc change would be enough:
@agg_clk_rate: array containing the aggregated clock rates in kHz
>
> Anyway:
>
> Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
>
> Thanks for going through the giant maze to fix this!
Thanks for being there along the way.. This spaghetti is far too much
for a single human..
Konrad
>
> Stephan
prev parent reply other threads:[~2023-06-10 19:09 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 20:19 [PATCH v2 00/22] Restructure RPM SMD ICC Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 01/22] soc: qcom: smd-rpm: Add QCOM_SMD_RPM_STATE_NUM Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 02/22] soc: qcom: smd-rpm: Use tabs for defines Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 03/22] clk: qcom: smd-rpm: Move some RPM resources to the common header Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 04/22] clk: qcom: smd-rpm: Export clock scaling availability Konrad Dybcio
2023-06-10 11:35 ` Stephan Gerhold
2023-06-10 12:15 ` Konrad Dybcio
2023-06-10 18:53 ` Konrad Dybcio
2023-06-10 19:25 ` Stephan Gerhold
2023-06-10 19:39 ` Konrad Dybcio
2023-06-11 9:20 ` Stephan Gerhold
2023-06-12 12:51 ` Konrad Dybcio
2023-06-12 17:03 ` Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 05/22] interconnect: qcom: icc-rpm: Introduce keep_alive Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 06/22] interconnect: qcom: icc-rpm: Allow negative QoS offset Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 07/22] interconnect: qcom: Fold smd-rpm.h into icc-rpm.h Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 08/22] interconnect: qcom: smd-rpm: Add rpmcc handling skeleton code Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 09/22] interconnect: qcom: Add missing headers in icc-rpm.h Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 10/22] interconnect: qcom: Define RPM bus clocks Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 11/22] interconnect: qcom: sdm660: Hook up RPM bus clk definitions Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 12/22] interconnect: qcom: msm8996: " Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 13/22] interconnect: qcom: qcs404: " Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 14/22] interconnect: qcom: msm8939: " Konrad Dybcio
2023-06-10 12:02 ` Stephan Gerhold
2023-06-09 20:19 ` [PATCH v2 15/22] interconnect: qcom: msm8916: " Konrad Dybcio
2023-06-10 12:02 ` Stephan Gerhold
2023-06-09 20:19 ` [PATCH v2 16/22] interconnect: qcom: qcm2290: " Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 17/22] interconnect: qcom: icc-rpm: Control bus rpmcc from icc Konrad Dybcio
2023-06-10 11:58 ` Stephan Gerhold
2023-06-10 12:14 ` Konrad Dybcio
2023-06-10 16:20 ` Stephan Gerhold
2023-06-10 17:54 ` Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 18/22] clk: qcom: smd-rpm: Separate out interconnect bus clocks Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 19/22] interconnect: qcom: icc-rpm: Fix bucket number Konrad Dybcio
2023-06-10 17:46 ` Stephan Gerhold
2023-06-10 17:53 ` Konrad Dybcio
2023-06-09 20:19 ` [PATCH v2 20/22] interconnect: qcom: icc-rpm: Set bandwidth on both contexts Konrad Dybcio
2023-06-10 18:00 ` Stephan Gerhold
2023-06-10 18:28 ` Konrad Dybcio
2023-06-10 18:43 ` Stephan Gerhold
2023-06-09 20:19 ` [PATCH v2 21/22] interconnect: qcom: icc-rpm: Set correct bandwidth through RPM bw req Konrad Dybcio
2023-06-10 18:46 ` Stephan Gerhold
2023-06-09 20:19 ` [PATCH v2 22/22] interconnect: qcom: icc-rpm: Fix bandwidth calculations Konrad Dybcio
2023-06-10 19:06 ` Stephan Gerhold
2023-06-10 19:09 ` Konrad Dybcio [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5362844c-253c-b624-c8f0-81a06a891dbd@linaro.org \
--to=konrad.dybcio@linaro.org \
--cc=agross@kernel.org \
--cc=andersson@kernel.org \
--cc=djakov@kernel.org \
--cc=evgreen@chromium.org \
--cc=leo.yan@linaro.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-clk@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=marijn.suijten@somainline.org \
--cc=mturquette@baylibre.com \
--cc=sboyd@kernel.org \
--cc=stephan@gerhold.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).