When processing a change request we have to construct the new content
for the changed file from the "diff" we receive. Before this CL we
calcualted a `LineInfo` to normally only use 1 entry in the list, then
calculated the new String, then calculated the new String once more.
This CL only gets the offset of the line we actually need (in what I
assume to be the normal case of only needing 1 line) and only calculates
the new string once for a reduction in processing time of about 50%.
For small files it probably wont matter much, but for bigger files it
will likely be noticeable.
To get the actual data in the benchmark this CL introduces `asJson` in
the timing pages, and picks out of the performance data the
"real number" for the change request. Turns out the overall number can
be very wrong because there's an async gap (where other stuff can be happening) between the calculation being done and the timing being
stopped.
Data:
Original -> Not doing the line starts:
Difference at 95.0% confidence
-284.7 +/- 35.8987
-33.0624% +/- 4.16893%
(Student's t, pooled s = 38.2065)
Not doing the line starts -> also not doing the newContent calculation twice:
Difference at 95.0% confidence
-207.2 +/- 31.3105
-35.9473% +/- 5.43207%
(Student's t, pooled s = 33.3233)
In total, i.e. from original -> this CL:
Difference at 95.0% confidence
-491.9 +/- 34.8949
-57.1246% +/- 4.05237%
(Student's t, pooled s = 37.1383)
This is with a size of 16,000 in the benchmark, but the processing should be linear so the ~57% decrease should be valid overall - although naturally in raw numbers it's not going to cut of ~half a second per 25 change requests in smaller files.
Raw data:
```
Original:
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":830,"size 16000: peak virtual memory size (kb)":2473160,"size 16000: total program size (virtual) (kb)":2309328,"size 16000: peak resident set size (\"high water mark\") (kb)":540228,"size 16000: size of memory portions (rss) (kb)":373328}
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":938,"size 16000: peak virtual memory size (kb)":2365488,"size 16000: total program size (virtual) (kb)":2306336,"size 16000: peak resident set size (\"high water mark\") (kb)":509212,"size 16000: size of memory portions (rss) (kb)":438796}
{"size 16000: Initial analysis (ms)":7,"size 16000: Processing time for 25 change requests (ms)":900,"size 16000: peak virtual memory size (kb)":2354420,"size 16000: total program size (virtual) (kb)":2300740,"size 16000: peak resident set size (\"high water mark\") (kb)":496768,"size 16000: size of memory portions (rss) (kb)":443892}
{"size 16000: Initial analysis (ms)":9,"size 16000: Processing time for 25 change requests (ms)":803,"size 16000: peak virtual memory size (kb)":2296448,"size 16000: total program size (virtual) (kb)":2223740,"size 16000: peak resident set size (\"high water mark\") (kb)":503040,"size 16000: size of memory portions (rss) (kb)":431608}
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":821,"size 16000: peak virtual memory size (kb)":2315888,"size 16000: total program size (virtual) (kb)":2158996,"size 16000: peak resident set size (\"high water mark\") (kb)":520212,"size 16000: size of memory portions (rss) (kb)":360704}
{"size 16000: Initial analysis (ms)":15,"size 16000: Processing time for 25 change requests (ms)":835,"size 16000: peak virtual memory size (kb)":2323752,"size 16000: total program size (virtual) (kb)":2215748,"size 16000: peak resident set size (\"high water mark\") (kb)":534380,"size 16000: size of memory portions (rss) (kb)":416532}
{"size 16000: Initial analysis (ms)":8,"size 16000: Processing time for 25 change requests (ms)":848,"size 16000: peak virtual memory size (kb)":2349108,"size 16000: total program size (virtual) (kb)":2219696,"size 16000: peak resident set size (\"high water mark\") (kb)":469712,"size 16000: size of memory portions (rss) (kb)":361812}
{"size 16000: Initial analysis (ms)":7,"size 16000: Processing time for 25 change requests (ms)":870,"size 16000: peak virtual memory size (kb)":2288416,"size 16000: total program size (virtual) (kb)":2204484,"size 16000: peak resident set size (\"high water mark\") (kb)":486716,"size 16000: size of memory portions (rss) (kb)":396940}
{"size 16000: Initial analysis (ms)":9,"size 16000: Processing time for 25 change requests (ms)":895,"size 16000: peak virtual memory size (kb)":2280008,"size 16000: total program size (virtual) (kb)":2188336,"size 16000: peak resident set size (\"high water mark\") (kb)":476664,"size 16000: size of memory portions (rss) (kb)":398232}
{"size 16000: Initial analysis (ms)":18,"size 16000: Processing time for 25 change requests (ms)":871,"size 16000: peak virtual memory size (kb)":2281128,"size 16000: total program size (virtual) (kb)":2216500,"size 16000: peak resident set size (\"high water mark\") (kb)":477080,"size 16000: size of memory portions (rss) (kb)":426856}
No line starts:
{"size 16000: Initial analysis (ms)":8,"size 16000: Processing time for 25 change requests (ms)":633,"size 16000: peak virtual memory size (kb)":2279560,"size 16000: total program size (virtual) (kb)":2169640,"size 16000: peak resident set size (\"high water mark\") (kb)":467740,"size 16000: size of memory portions (rss) (kb)":365508}
{"size 16000: Initial analysis (ms)":9,"size 16000: Processing time for 25 change requests (ms)":578,"size 16000: peak virtual memory size (kb)":2481552,"size 16000: total program size (virtual) (kb)":2307804,"size 16000: peak resident set size (\"high water mark\") (kb)":547824,"size 16000: size of memory portions (rss) (kb)":370972}
{"size 16000: Initial analysis (ms)":6,"size 16000: Processing time for 25 change requests (ms)":568,"size 16000: peak virtual memory size (kb)":2412752,"size 16000: total program size (virtual) (kb)":2301564,"size 16000: peak resident set size (\"high water mark\") (kb)":546168,"size 16000: size of memory portions (rss) (kb)":447020}
{"size 16000: Initial analysis (ms)":5,"size 16000: Processing time for 25 change requests (ms)":530,"size 16000: peak virtual memory size (kb)":2426432,"size 16000: total program size (virtual) (kb)":2364240,"size 16000: peak resident set size (\"high water mark\") (kb)":565100,"size 16000: size of memory portions (rss) (kb)":503364}
{"size 16000: Initial analysis (ms)":12,"size 16000: Processing time for 25 change requests (ms)":620,"size 16000: peak virtual memory size (kb)":2276668,"size 16000: total program size (virtual) (kb)":2226296,"size 16000: peak resident set size (\"high water mark\") (kb)":477488,"size 16000: size of memory portions (rss) (kb)":434240}
{"size 16000: Initial analysis (ms)":12,"size 16000: Processing time for 25 change requests (ms)":534,"size 16000: peak virtual memory size (kb)":2391200,"size 16000: total program size (virtual) (kb)":2349392,"size 16000: peak resident set size (\"high water mark\") (kb)":531700,"size 16000: size of memory portions (rss) (kb)":490400}
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":588,"size 16000: peak virtual memory size (kb)":2377112,"size 16000: total program size (virtual) (kb)":2278476,"size 16000: peak resident set size (\"high water mark\") (kb)":518740,"size 16000: size of memory portions (rss) (kb)":412952}
{"size 16000: Initial analysis (ms)":10,"size 16000: Processing time for 25 change requests (ms)":589,"size 16000: peak virtual memory size (kb)":2373204,"size 16000: total program size (virtual) (kb)":2258000,"size 16000: peak resident set size (\"high water mark\") (kb)":516188,"size 16000: size of memory portions (rss) (kb)":390972}
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":583,"size 16000: peak virtual memory size (kb)":2349184,"size 16000: total program size (virtual) (kb)":2206488,"size 16000: peak resident set size (\"high water mark\") (kb)":555888,"size 16000: size of memory portions (rss) (kb)":404356}
{"size 16000: Initial analysis (ms)":9,"size 16000: Processing time for 25 change requests (ms)":541,"size 16000: peak virtual memory size (kb)":2335140,"size 16000: total program size (virtual) (kb)":2227132,"size 16000: peak resident set size (\"high water mark\") (kb)":540204,"size 16000: size of memory portions (rss) (kb)":433256}
Additionally don't do it twice:
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":379,"size 16000: peak virtual memory size (kb)":2274520,"size 16000: total program size (virtual) (kb)":2197944,"size 16000: peak resident set size (\"high water mark\") (kb)":470816,"size 16000: size of memory portions (rss) (kb)":393124}
{"size 16000: Initial analysis (ms)":8,"size 16000: Processing time for 25 change requests (ms)":431,"size 16000: peak virtual memory size (kb)":2353820,"size 16000: total program size (virtual) (kb)":2287616,"size 16000: peak resident set size (\"high water mark\") (kb)":494148,"size 16000: size of memory portions (rss) (kb)":428836}
{"size 16000: Initial analysis (ms)":15,"size 16000: Processing time for 25 change requests (ms)":334,"size 16000: peak virtual memory size (kb)":2210904,"size 16000: total program size (virtual) (kb)":2164796,"size 16000: peak resident set size (\"high water mark\") (kb)":472180,"size 16000: size of memory portions (rss) (kb)":437368}
{"size 16000: Initial analysis (ms)":16,"size 16000: Processing time for 25 change requests (ms)":364,"size 16000: peak virtual memory size (kb)":2284260,"size 16000: total program size (virtual) (kb)":2239292,"size 16000: peak resident set size (\"high water mark\") (kb)":482420,"size 16000: size of memory portions (rss) (kb)":437232}
{"size 16000: Initial analysis (ms)":8,"size 16000: Processing time for 25 change requests (ms)":397,"size 16000: peak virtual memory size (kb)":2148164,"size 16000: total program size (virtual) (kb)":2118072,"size 16000: peak resident set size (\"high water mark\") (kb)":479676,"size 16000: size of memory portions (rss) (kb)":446752}
{"size 16000: Initial analysis (ms)":5,"size 16000: Processing time for 25 change requests (ms)":327,"size 16000: peak virtual memory size (kb)":2292012,"size 16000: total program size (virtual) (kb)":2269972,"size 16000: peak resident set size (\"high water mark\") (kb)":487932,"size 16000: size of memory portions (rss) (kb)":476524}
{"size 16000: Initial analysis (ms)":8,"size 16000: Processing time for 25 change requests (ms)":339,"size 16000: peak virtual memory size (kb)":2348844,"size 16000: total program size (virtual) (kb)":2286660,"size 16000: peak resident set size (\"high water mark\") (kb)":484112,"size 16000: size of memory portions (rss) (kb)":432036}
{"size 16000: Initial analysis (ms)":16,"size 16000: Processing time for 25 change requests (ms)":393,"size 16000: peak virtual memory size (kb)":2277080,"size 16000: total program size (virtual) (kb)":2248636,"size 16000: peak resident set size (\"high water mark\") (kb)":472864,"size 16000: size of memory portions (rss) (kb)":440092}
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":365,"size 16000: peak virtual memory size (kb)":2397828,"size 16000: total program size (virtual) (kb)":2201648,"size 16000: peak resident set size (\"high water mark\") (kb)":530176,"size 16000: size of memory portions (rss) (kb)":334264}
{"size 16000: Initial analysis (ms)":11,"size 16000: Processing time for 25 change requests (ms)":363,"size 16000: peak virtual memory size (kb)":2286312,"size 16000: total program size (virtual) (kb)":2253760,"size 16000: peak resident set size (\"high water mark\") (kb)":480004,"size 16000: size of memory portions (rss) (kb)":464720}
```
Change-Id: If122d4667da677fc07cab83ae97135d3a7ac99d9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/457722
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
Jens Johansen
b1c6707027