Re: [PATCH v9 00/13] Don't compute events that won't be used in a metric.

John Garry
2021-09-29T15:16:11Z

On 23/09/2021 08:46, Ian Rogers wrote:
> For a metric like:
> EVENT1 if #smt_on else EVENT2
>
> currently EVENT1 and EVENT2 will be measured and then when the metric
> is reported EVENT1 or EVENT2 will be printed depending on the value
> from smt_on() during the expr parsing. Computing both events is
> unnecessary and can lead to multiplexing as discussed in this thread:
> https://lore.kernel.org/lkml/20201110100346.2527031-1-irogers@google.com/
>
> This change modifies expression parsing so that constants are
> considered when building the set of ids (events) and only events not
> contributing to a constant value are measured.

Based on some testing on my arm64 platform, no regression seen, so:

Tested-by: John Garry <john.garry@huawei.com>