build: Added build support for jemalloc.#315
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Back in 2024 Bitcoin Core added support for an alternative memory allocator called jemalloc. bitcoin#25569 However, support was never added to the build environment. This is primarily a cmake change to enable support to link in the jemalloc library, and a tiny documentation update. There are no source code changes. I have modelled this change off WITH_ZMQ. Keys steps to use jemalloc are: sudo sudo apt install libjemalloc-dev cmake -B build -DWITH_JEMALLOC=ON cmake --build build The problem I am trying to solve is how to improve the performance of Bitcoin Knots for miners. Pool's frequently exercise RPC functions that involve a lot of JSON processing, such as getblocktemplate. When I use the following benchmark: bench_bitcoin -filter="RpcMempool" -min-time=15000 I get a 30% performance improvement when jemalloc is used. When I run the entire benchmark suite there are no performance regressions of note (two performed very slightly slower, but so little I consider it within test error margins). You can confirm jemalloc has been built into the executables with: ldd build/bin/bitcoind | grep jemalloc ldd build/bin/bitcoin-cli | grep jemalloc You can enable memory allocation performance information with a command like: MALLOC_CONF="stats_print:true" bitcoind This will cause a lot of data to be displayed after the executable exits. I have run the following test suite on Linux, and everything passed. cd ~/bitcoin/build ctest --output-on-failure
Ari4ka
approved these changes
Jun 21, 2026
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Back in 2024 Bitcoin Core added support for an alternative memory allocator called jemalloc. bitcoin#25569
However, support was never added to the build environment.
This is primarily a cmake change to enable support to link in the jemalloc library, and a tiny documentation update. There are no source code changes. I have modelled this change off WITH_ZMQ. Keys steps to use jemalloc are:
sudo sudo apt install libjemalloc-dev
cmake -B build -DWITH_JEMALLOC=ON
cmake --build build
The problem I am trying to solve is how to improve the performance of Bitcoin Knots for miners. Pool's frequently exercise RPC functions that involve a lot of JSON processing, such as getblocktemplate. When I use the following benchmark:
bench_bitcoin -filter="RpcMempool" -min-time=15000
I get a 30% performance improvement when jemalloc is used. When I run the entire benchmark suite there are no performance regressions of note (two performed very slightly slower, but so little I consider it within test error margins).
You can confirm jemalloc has been built into the executables with: ldd build/bin/bitcoind | grep jemalloc
ldd build/bin/bitcoin-cli | grep jemalloc
You can enable memory allocation performance information with a command like: MALLOC_CONF="stats_print:true" bitcoind
This will cause a lot of data to be displayed after the executable exits.
I have run the following test suite on Linux, and everything passed. cd ~/bitcoin/build
ctest --output-on-failure