Simorgh performance profiling

[chris-hinds]

Description

During the last loadtest on Simorgh we saw it scale to 8 instances with a peak CPU utilisation of ~65% across the 8 instances. For load traffic profile of just 105 r/ps this seem very high.

We should try and identify any potential performance bottlenecks in the Simorgh application and the express server in a bid to see if we can spot any issues, e.g. long running functions, synchronous tasks, async data fetching etc.

Or is JS and React SSR just resource heavy in general?

There are a number of different node profiling tools that we can use on our local machine to to simulate load and to build a picture of what is actually happening when rendering pages. This may help us to identify areas for improvement.

Some tools that come to mind are:

• The ReactJS Profiler API https://reactjs.org/docs/profiler.html
• The suite of tools from NearForm https://clinicjs.org/
• The built in FlameGraphs on Chrome Dev tools

This issue should be worked on as a group, different members of the various WS teams have used these profiling tools before and it would be good to get together as a small group and run a session on profiling the Simorgh application and seeing what we can find.

• output of this would be to create issues to identify what needs doing.

[simonsinclair]

I started looking into this this morning and added some initial thoughts to https://paper.dropbox.com/doc/Simorgh-SSR-performance--A4hTqJpWFm5zO42rxhdgLpSqAQ-z1ffIgMu97RMinpYS4blG.

[joshcoventry]

@simonsinclair Is this now blocked until we can progress updating styled components to v5, is there anything else we can do?

[simonsinclair]

@simonsinclair Is this now blocked until we can progress updating styled components to v5, is there anything else we can do?

It's not blocked, but needs some more time allocated to progress following a decision in the WS Tech group on Tuesday. We discussed yesterday that that time might be in a week following the Ad's kick-off and Ukrainian STY release.

The work will involve a proof-of-concept and require a release candidate of all packages in Psammead.

[simonsinclair]

A number of issues have been completed following the initial profiling conducted in relation to this issue – each one nudging us towards migrating to Emotion, which is now the agreed direction. This issue will now be closed.

The following issue has been created to track the migration from Styled Components to Emotion:  #7772.