Messages in this thread | | | Date | Mon, 5 Dec 2022 12:56:45 +0000 | Subject | Re: [PATCH v3] perf jevents: Parse metrics during conversion | From | John Garry <> |
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On 05/12/2022 12:53, Arnaldo Carvalho de Melo wrote: > Em Wed, Nov 30, 2022 at 07:41:38PM -0800, Ian Rogers escreveu: >> Currently the 'MetricExpr' json value is passed from the json >> file to the pmu-events.c. This change introduces an expression >> tree that is parsed into. The parsing is done largely by using >> operator overloading and python's 'eval' function. Two advantages >> in doing this are: >> >> 1) Broken metrics fail at compile time rather than relying on >> `perf test` to detect. `perf test` remains relevant for checking >> event encoding and actual metric use. >> >> 2) The conversion to a string from the tree can minimize the metric's >> string size, for example, preferring 1e6 over 1000000, avoiding >> multiplication by 1 and removing unnecessary whitespace. On x86 >> this reduces the string size by 3,050bytes (0.07%). >> >> In future changes it would be possible to programmatically >> generate the json expressions (a single line of text and so a >> pain to write manually) for an architecture using the expression >> tree. This could avoid copy-pasting metrics for all architecture >> variants. >> >> Signed-off-by: Ian Rogers<irogers@google.com> >> >> v3. Avoids generic types on standard types like set that aren't >> supported until Python 3.9, fixing an issue with Python 3.6 >> reported-by John Garry. v3 also fixes minor pylint issues and adds >> a call to Simplify on the read expression tree. > Cool, John looked reviewed it (may I add the tag?). Applying to my local > tree, will do some light testing.
Actually I just got as far as testing v2 (which gave rise to this v3). I will look at it further today.
Thanks, John
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