fuzz: Avoid extraneous copy of input data, using Span<> #20839

pull MarcoFalke wants to merge 1 commits into bitcoin:master from MarcoFalke:2101-fuzzSpan changing 4 files +10 −11

MarcoFalke commented at 4:30 PM on January 3, 2021: member

Seeing speedup here in the fuzz framework part (non-fuzz-target part). Speedup is only visible for input data larger than 100kB.
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DrahtBot commented at 6:40 PM on January 3, 2021: member


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Conflicts

Reviewers, this pull request conflicts with the following ones:
- #20663 (fuzz: Hide script_assets_test_minimizer by MarcoFalke)
If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.
MarcoFalke removed the label GUI on Jan 3, 2021
MarcoFalke removed the label RPC/REST/ZMQ on Jan 3, 2021
MarcoFalke removed the label UTXO Db and Indexes on Jan 3, 2021
MarcoFalke removed the label Wallet on Jan 3, 2021
MarcoFalke added the label Tests on Jan 3, 2021
practicalswift commented at 9:09 PM on January 12, 2021: contributor

Seeing 5% speedup here in the fuzz framework part (non-fuzz-target part)

Nice! Can you share the benchmarks and/or details on how to reproduce? :)
laanwj commented at 2:18 PM on February 1, 2021: member

Concept ACK , can be rebased and maybe opened for review now that #20464 is merged.
fuzz: Avoid extraneous copy of input data, using Span<> faf7d7418c
MarcoFalke force-pushed on Feb 3, 2021
MarcoFalke marked this as ready for review on Feb 3, 2021

MarcoFalke commented at 6:57 PM on February 3, 2021: member

To reproduce:

diff --git a/src/test/fuzz/string.cpp b/src/test/fuzz/string.cpp
index 282a2cd8ca..7a1c7b00d6 100644
--- a/src/test/fuzz/string.cpp
+++ b/src/test/fuzz/string.cpp
@@ -33,6 +33,16 @@
 #include <string>
 #include <vector>
 
+FUZZ_TARGET(max_throughput)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    assert(
+        // "Teach" libFuzzer to explore long sequences (needs -use_value_profile=1 -len_control=1 -max_len=2000000)
+        fuzzed_data_provider.remaining_bytes() < 500'000 ||
+        // Make it crash when done
+        fuzzed_data_provider.ConsumeBool());
+}
+
 FUZZ_TARGET(string)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());

Then run a bunch and plot all (lim, exec/s).

FUZZ=max_throughput ./src/test/fuzz/fuzz -use_value_profile=1 -len_control=1 -max_len=2000000

MarcoFalke commented at 7:20 PM on February 3, 2021: member

My result (N=10, Firefox was running in the background, so take with a span of salt):
practicalswift commented at 9:07 PM on February 4, 2021: contributor

cr ACK faf7d7418cf01cb04cd457bcc630654da958a777: patch looks correct :)
laanwj commented at 1:56 PM on February 5, 2021: member

That chart is a work of art :smile:

Code review ACK faf7d7418cf01cb04cd457bcc630654da958a777
laanwj merged this on Feb 5, 2021
laanwj closed this on Feb 5, 2021
MarcoFalke deleted the branch on Feb 5, 2021
sidhujag referenced this in commit 8d5ae0a11e on Feb 5, 2021
DrahtBot locked this on Aug 16, 2022

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fuzz: Avoid extraneous copy of input data, using Span<> #20839

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