WIP estimating validation bit rate

Author: nfrisby

scripts/estimating-validation-bitrate/README

@@ -0,0 +1,70 @@
+- `db-analyser --benchmark-ledger-ops` lists the fixed stats, and then for Byron and Shelley it currently also lists the number of txs and the total size of the txs.
+
+- `db-analyser --show-block-header-size` lists the size of the block's header.
+  I ran a patched version that also simply includes the block size.
+
+- `MsgBlock` has an overhead of 2 bytes (ie the list length and the word tag, since both are <24).
+
+- I _think_ `network-mux`'s SDU overhead is 8 bytes, from https://github.com/IntersectMBO/ouroboros-network/blob/db61131c2f375842f0930a8a9cf7f83b0cb80992/network-mux/src/Network/Mux/Codec.hs#L28-L40.
+  However, I don't know how many SDUs each byte requires.
+  So I'll omit this.
+ 
+Thus the number of bytes in each block that are carried by the `network-mux` is: 2 + 1 + hdrSize + txSize.
+
+-----
+
+The basic idea of this simple script is to divide real-world time up into non-overlapping 10 second chunks.
+We use only mutator time, essentially assuming that GC is instantaneous; this conservatively _over_-estimates the effective bit rate.
+Map each chunk to the set of blocks whose validation began during that chunk.
+Then divide the sum of the validation mutator duration for each block by the sum of the on-the-wire size of each.
+
+First, a sanity check.
+
+```
+$ cat show-block-header-size.txt | awk '($4 != "SlotNo") {print $0} ($6 != "header") {print $0}'
+[0.834136s] Started ShowBlockHeaderSize
+[0.834136s] Started ShowBlockHeaderSize
+[1926.666379s] Maximum encountered header size = 1012
+[1926.666379s] Maximum encountered header size = 1012
+[1926.666504s] Done
+[1926.666504s] Done
+ImmutableDB tip: At (Block {blockPointSlot = SlotNo 133220620, blockPointHash = 8b0597e7cf5c65b9d00af8a162d30eaae6647f868224004b02d7bd30e1d3f93f})
+ImmutableDB tip: At (Block {blockPointSlot = SlotNo 133220620, blockPointHash = 8b0597e7cf5c65b9d00af8a162d30eaae6647f868224004b02d7bd30e1d3f93f})
+```
+ 
+Then, the real plot as well as another sanity check of the number of blocks mapped to each 10 second chunk of mutator time.
+
+The assumed inputs are benchmark-ledger-ops.csv and patched-show-block-header-sizes.txt, where the latter used a patched `db-analyser` to include an additional column for `GetBlockSize`.
+(The sum of the `txSizes` in the `..era-specific stats` is a slight underestimate.)
+
+```
+$ cat benchmark-ledger-ops.csv | cut -d'   ' -f1,12,13 | tail -n+2 >SlotNo-BodyTickDur-BodyAppDur.txt
+$ paste SlotNo-BodyTickDur-BodyAppDur.txt <(tail -n+2 patched-show-block-header-sizes.txt)  | gawk 'BEGIN {CONVFMT="%.18g" } ($1 != $8) { exit} {x = x + $2 + $3; y = y + 2 + $14; print $1, x, y}' > SlotNo-CumuDur-CumuSize.txt
+$ cat SlotNo-CumuDur-CumuSize.txt | gawk 'BEGIN {w = 10; CONVFMT="%.18g"; prevX = -1; prevY = 0; prevZ = 0} {x = int($2 / (1000 * 1000 * w)); y = $3} (x != prevX) {print $1, (y - prevY) / w * 8 / (1000*1000), NR - prevZ; prevY = y; prevZ = NR} {prevX = x}' >catch
+$ tail -n1 SlotNo-CumuDur-CumuSize.txt 
+133075481 140291882237 190610147733
+$ head -n1000 gp.scr*
+==> gp.scr <==
+set multiplot layout 2,1
+
+set title  'Validation Bit Rate (on an AMD EPYC 7702P)'
+
+set xlabel 'slot number of the last block in each 10 second chunk (millions of slots)'
+set ylabel 'bytes validated per 10 second chunk of mutator time (megabits per second)'
+
+plot 'catch' using 1:2 notitle
+
+set yrange [0:25]
+
+unset title
+set xlabel 'same'
+set ylabel 'same, clamped to 25'
+
+plot 'catch' using 1:($2 > 25 ? 25 : $2) notitle
+
+==> gp.scr2 <==
+set xlabel 'slot number of the last block in each 10 second chunk (millions of slots)'
+set ylabel 'blocks per 10 second chunk of mutator time, clamped to 1000'
+
+plot 'catch' using 1:(1000 < $3 ? 1000 : $3) notitle
+```

scripts/estimating-validation-bitrate/gp.scr

@@ -0,0 +1,16 @@
+set multiplot layout 2,1
+
+set title  'Validation Bit Rate'
+
+set xlabel 'slot number of the last block in each 10 second chunk (millions of slots)'
+set ylabel 'bytes validated per 10 second chunk of mutator time (megabits per second)'
+
+plot 'catch' using ($1 / 1000000):2 notitle
+
+set yrange [0:25]
+
+unset title
+set xlabel 'same'
+set ylabel 'same, clamped to 25'
+
+plot 'catch' using ($1 / 1000000):($2 > 25 ? 25 : $2) notitle

scripts/estimating-validation-bitrate/gp.scr2

@@ -0,0 +1,4 @@
+set xlabel 'slot number (at end of each 10 second chunk)'
+set ylabel 'blocks per 10 second chunk of mutator time, clamped to 1000'
+
+plot 'catch' using 1:(1000 < $3 ? 1000 : $3) notitle