On Tuesday, January 16, 2018 4:33:12 AM CET Luke Diamand wrote: > Hi! > > I could be wrong about this, but I'm finding a roughly 10x slowdown on > ARM between 1.2.1 and current HEAD (e1ca8748). > > I have a small test program here: > > https://gist.github.com/luked99/7c67d94da5c33cac5a1b41a500013355 > > On my Raspberry Pi 2, this is getting ~180us to do a self-backtrace in > 1.2.1 and around 1.8ms in HEAD. > > I tried running perf, and that seems to be saying that it is opening > and closing files a lot.
How did you run perf? For starters, can you use `perf stat` on the two versions and your benchmark so that we can see whether it's CPU bound or not? Then, please record a profile with perf record --call-graph dwarf and then inspect that with "perf report" on your ARM machine or hotspot [1] on your devel machine, assuming you have a sysroot with the debug symbols available there. This should make it much easier to find out where the performance is going to. [1]: https://github.com/KDAB/hotspot > I also had a go at git bisecting, but there's a separate bug which was > introduced and then fixed which caused it to segfault, which overlaps > with this problem, along with some other performance regression fixes. > > 90d0d15c4ec3bb812dcb44c081757ebf6756cc6b didn't crash, but was slow. > 2a5d1a629634b3225fccb1ed8a0a765bccc77f2e crashed. > v1.2.1 is fast. > > I'm configuring with: > > CC=arm-linux-gnueabihf-gcc CFLAGS="-g" configure --disable-debug > --host=arm-linux \ > --enable-shared --disable-static --with-sysroot=/home/lgd/arm > --enable-maintainer-mode \ > --disable-debug-frame --disable-block-signals > > Any ideas as to what's going on? > > Thanks > Luke > > _______________________________________________ > Libunwind-devel mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/libunwind-devel -- Milian Wolff [email protected] http://milianw.de _______________________________________________ Libunwind-devel mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/libunwind-devel
