On Wed, Sep 05, 2018 at 11:55:39AM -0700, Andres Freund wrote: > On 2018-08-22 06:20:21 +0000, Noah Misch wrote: > > I see jit slows the regression tests considerably: > > Is this with LLVM assertions enabled or not?
Without, I think. I configured them like this: cmake -G Ninja -DCMAKE_INSTALL_PREFIX=$HOME/sw/nopath/llvm -DCMAKE_BUILD_TYPE=MinSizeRel -DLLVM_USE_LINKER=gold -DLLVM_TARGETS_TO_BUILD=X86 ../llvm cmake -G Ninja -DCMAKE_INSTALL_PREFIX=$HOME/sw/nopath/llvm-el32 -DCMAKE_BUILD_TYPE=MinSizeRel -DLLVM_USE_LINKER=gold -DLLVM_PARALLEL_LINK_JOBS=1 ../llvm > > # mips32el, assert, w/o llvm (buildfarm member topminnow) [1] > > 28min install-check-* > > 35min check-pg_upgrade > > > > # mips32el, assert, w/ llvm 6.0.1 [1] > > 63min install-check-* > > 166min check-pg_upgrade > > But this seems so absurdly large of a difference that I kinda think LLVM > assertions (wich are really expensive and add O(N) operations in a bunch > of places) might be to blame. The 2018-08-25 and 2018-09-01 published runs were far less bad. Most of the blame goes to the reason given in the footnote (competing load on a shared machine), not to JIT.
