Support old CPUs #22
Support old CPUs #22
Conversation
There was a problem hiding this comment.
I have mixed feelings about this since this will disable more than SSE4.2 (thread locals, fallocate, sync_file_range and adaptive mutexes). This probably doesn't impact performance that much (we were already building with all of these features disabled until recently), but it's one of the main reasons I wanted to migrate the build to CMake. Unfortunately I already had to do make some changes to CMakeLists.txt to make it build properly for ARM, all commit messages that start with rocksdb: basically change something in the rocksdb subtree, so yeah we might have to deal with some conflicts when we pull again from rocksdb (I also had to cherry-pick some commits to fix build issues IIRC). Still, this is probably the easiest/fastest way to fix the issue right now and publish a parity-ethereum binary that doesn't cause any compatibility issues. I guess we can create an issue to remove the PORTABLE flag in the future and make more fine-grained adjustments to CMakeLists.txt.
rocksdb-sys/build.rs
Outdated
| } | ||
| // Added to support old CPUs | ||
| // see https://github.com/paritytech/parity-ethereum/issues/9684 | ||
| cfg.define("PORTABLE", "ON"); |
There was a problem hiding this comment.
Maybe we could use an env variable to allow compiling with PORTABLE=OFF, so that we distribute portable binaries, but allow compiling from source with all the features for ultimate performance?
|
Good idea, I was going to suggest using a cargo feature but it's probably easier to use an environment variable (since with a feature we'd need to add it to |
I could modify
CMakeLists.txtto something like-march=core2and/arch:AVXon Windows, but not sure it is the best way, since it would probably create conflicts when updating RocksDB and there are some checks like this one that needs to be removed as well. Also I haven't tested this (don't have a new CPU atm) and don't know what the performance impact is.Alternatively, we can say that the binaries support only new CPUs and one needs to build from source on an old CPU if needed, but that doesn't seem like a good approach to me, especially in case of Windows.
related to openethereum/parity-ethereum#9684.