Changeset 5438e41 for doc/theses/andrew_beach_MMath

Timestamp:

Aug 9, 2021, 4:11:10 PM (3 years ago)

Author:

Andrew Beach <ajbeach@…>

Branches:

ADT, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

50b29d9, f42a6b8

Parents:

9373b6a

Message:

Andrew MMath: Had some bad performance numbers, updated the description as well.

File:

• doc/theses/andrew_beach_MMath/performance.tex (modified) (4 diffs)

doc/theses/andrew_beach_MMath/performance.tex

@@ -160 +160 @@
 % Match All     &   3719462155 &   43294042 &   3223004977 &  1286054154 &   623887874 \\
 % Match None    &   4971630929 &   55311709 &   9481225467 &  1310251289 &   623752624 \\
+%
+% run-algol-04-a
+% --------------
+% Raise Empty   & 0.0 & 0.0 &  3250260945 & 0.0 & 0.0 \\
+% Raise D'tor   & 0.0 & 0.0 & 29017675113 & N/A & N/A \\
+% Raise Finally & 0.0 & 0.0 &         N/A & 0.0 & 0.0 \\
+% Raise Other   & 0.0 & 0.0 & 24411823773 & 0.0 & 0.0 \\
+% Cross Handler & 0.0 & 0.0 &      769334 & 0.0 & 0.0 \\
+% Cross Finally & 0.0 & N/A &         N/A & 0.0 & 0.0 \\
+% Match All     & 0.0 & 0.0 &  3254283504 & 0.0 & 0.0 \\
+% Match None    & 0.0 & 0.0 &  9476060146 & 0.0 & 0.0 \\
+
 \begin{tabular}{|l|c c c c c|}
 \hline
@@ -196 +208 @@
 % Match All     &   3189512499 &   39124453 &   2667795989 &  1525889031 &   733785613 \\
 % Match None    &   4094675477 &   48749857 &   7850618572 &  1566713577 &   733478963 \\
+%
+% run-plg7a-04-a
+% --------------
+% 0.0 are unfilled.
+% Raise Empty   & 0.0 & 0.0 &  2770781479 & 0.0 & 0.0 \\
+% Raise D'tor   & 0.0 & 0.0 & 23530084907 & N/A & N/A \\
+% Raise Finally & 0.0 & 0.0 &         N/A & 0.0 & 0.0 \\
+% Raise Other   & 0.0 & 0.0 & 23816827982 & 0.0 & 0.0 \\
+% Cross Handler & 0.0 & 0.0 &     1422188 & 0.0 & 0.0 \\
+% Cross Finally & 0.0 & N/A &         N/A & 0.0 & 0.0 \\
+% Match All     & 0.0 & 0.0 &  2671989778 & 0.0 & 0.0 \\
+% Match None    & 0.0 & 0.0 &  7829059869 & 0.0 & 0.0 \\
 
 % PLG7A (in seconds)
@@ -202 +226 @@
               & \CFA (Terminate) & \CFA (Resume) & \Cpp & Java & Python \\
 \hline
-% Raise Empty   & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\
-% Raise D'tor   & 0.0 & 0.0 & 0.0 & N/A & N/A \\
-% Raise Finally & 0.0 & 0.0 & N/A & 0.0 & 0.0 \\
-% Raise Other   & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\
-% Cross Handler & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\
-% Cross Finally & 0.0 & N/A & N/A & 0.0 & 0.0 \\
-% Match All     & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\
-% Match None    & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\
 Raise Empty   & 0.0 & 0.0 & 0.0 & 0.0 & 0.0 \\
 Raise D'tor   & 0.0 & 0.0 & 0.0 & N/A & N/A \\
@@ -231 +247 @@
 
 This means that while \CFA does not actually keep up with Python in every
-case it is no worse than roughly half the speed of \Cpp. This is good
+case it is usually no worse than roughly half the speed of \Cpp. This is good
 enough for the prototyping purposes of the project.
 
-One difference not shown is that optimizations in \CFA is very fragile.
-The \CFA compiler uses gcc as part of its complation process and the version
-of gcc could change the speed of some of the benchmarks by 10 times or more.
-Similar changes to g++ for the \Cpp benchmarks had no significant changes.
-Because of the connection between gcc and g++; this suggests it is not the
-optimizations that are changing but how the optimizer is detecting if the
-optimizations can be applied. So the optimizations are always applied in
-g++, but only newer versions of gcc can detect that they can be applied in
-the more complex \CFA code.
+The test case where \CFA falls short is Raise Other, the case where the
+stack is unwound including a bunch of non-matching handlers.
+This slowdown seems to come from missing optimizations,
+the results above came from gcc/g++ 10 (gcc as \CFA backend or g++ for \Cpp)
+but the results change if they are run in gcc/g++ 9 instead.
+Importantly, there is a huge slowdown in \Cpp's results bringing that brings
+\CFA's performace back in that roughly half speed area. However many other
+\CFA benchmarks increase their run-time by a similar amount falling far
+behind their \Cpp counter-parts.
+
+This suggests that the performance issue in Raise Other is just an
+optimization not being applied. Later versions of gcc may be able to
+optimize this case further, at least down to the half of \Cpp mark.
+A \CFA compiler that directly produced assembly could do even better as it
+would not have to work across some of \CFA's current abstractions, like
+the try terminate function.
 
 Resumption exception handling is also incredibly fast. Often an order of