Patch for telemetry design

[Matuszczak, Piotr]

Hi Justin, 

>I've taken a read through the design proposal as more of a client of the telemetry data. I like this proposal quite a bit as it is pretty clear. I had a couple of >questions and given the broad level, I wasn't sure if gerrit was the right place for them.

In fact, this patch is covering few changes that we've made to D-Bus API during the development and integration. 

>On Timestamps, are the timestamps done per metric(sensor reading) or per report. This wasn't clear to me from the design proposal, and also it was hard to >tell where the timestamp was being set.

Timestamps are gathered for both, metrics and report. Timestamp for metric is the timestamp of D-Bus senor update, while timestamp of the report is for the report update. It corresponds with the Redfish Metric Report resource, where both, individual metrics and the whole report have their update timestamps. 

>From the performance tests section, is there a limit on the number of sensors per report, seemingly it is 10, or was this done to simplify the performance >testing?

It was done because of limited sensors support on the test platform.

>The other general question I had was around the amount of data being transmitted. For instance, if you're getting reports on every sensor in the system >(100s) the report(s) could be huge at scale. Would there be an option of considering compressed data like BEJSON? Or is this feedback that should go to the >DMTF?

First of all, the max number of supported reports will be limited to around 50 due to limited BMC resources. As for the using compressed data, if we would like to compress data for the IPC (D-Bus) it is possible for us to implement any format we like as long as we document it in the design. As for the using compressed format for the Redfish Metric report it will require acceptance from the DMTF, because it will require changes in the schema. 
You were referring to using BSON on D-Bus or in Redfish Metric Report schema?

Piotr Matuszczak
---------------------------------------------------------------------
Intel Technology Poland sp. z o.o. 
ul. Slowackiego 173, 80-298 Gdansk
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-----Original Message-----
From: openbmc <openbmc-bounces+piotr.matuszczak=intel.com at lists.ozlabs.org> On Behalf Of Justin Thaler
Sent: Tuesday, June 16, 2020 8:05 PM
To: openbmc at lists.ozlabs.org
Subject: Re: Patch for telemetry design

Hi Piotr,
	I've taken a read through the design proposal as more of a client of the telemetry data. I like this proposal quite a bit as it is pretty clear. I had a couple of questions and given the broad level, I wasn't sure if gerrit was the right place for them.

On Timestamps, are the timestamps done per metric(sensor reading) or per report. This wasn't clear to me from the design proposal, and also it was hard to tell where the timestamp was being set.

 From the performance tests section, is there a limit on the number of sensors per report, seemingly it is 10, or was this done to simplify the performance testing?

The other general question I had was around the amount of data being transmitted. For instance, if you're getting reports on every sensor in the system (100s) the report(s) could be huge at scale. Would there be an option of considering compressed data like BEJSON? Or is this feedback that should go to the DMTF?

Thanks,
Justin Thaler
IBM RAS Engineer

On 6/16/20 4:31 AM, Matuszczak, Piotr wrote:
> Hi,
> 
> I've uploaded patch for telemetry service design some time ago. I would like to ask you for review.
> https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/31690
> 
> 
> Piotr Matuszczak
> ---------------------------------------------------------------------
> Intel Technology Poland sp. z o.o.
> ul. Slowackiego 173, 80-298 Gdansk
> KRS 101882
> NIP 957-07-52-316
>