[jemalloc-4.2.1]Can't profile heap on ARM target

[Jason Evans]

On Jun 27, 2016, at 7:38 PM, 郑魁 <zack93 at 126.com> wrote:
> Hi all, I was trying HeapProf on ARM target, But always get a Empty call stack. 
> Step:
> 1. cross-compile jemalloc-4.2.1 (./configure --build=x86_64-unknown-linux-gnu --host=arm-none-linux-gnueabi EXTRA_CFLAGS="-fno-omit-frame-pointer -DUSE_UTF8 -O2 -fPIC -std=gnu99 " LDFLAGS=" -fPIC -std=gnu99" CC="arm-linux-gnueabi-gcc" CXX="arm-linux-gnueabihf-g++" AR="arm-linux-gnueabihf-ar" CFLAGS="-O2" --enable-debug --enable-prof
> ) and test.c (a very simple code)
> 2. running "MALLOC_CONF=stats_print:true LD_PRELOAD=/usr/lib/libjemalloc.so ./test" , Yes, it works!
> 3. Try profile heap like following: 
>     MALLOC_CONF=prof:true,lg_prof_sample:0,prof_final:true LD_PRELOAD=/usr/lib/libjemalloc.so ./test
> then get heap file "jeprof.10678.0.f.heap" with empty call stack:
> /tmp/jemalloc # cat jeprof.10678.0.f.heap
> cat jeprof.10678.0.f.heap
> heap_v2/1
>   t*: 1000: 54673752 [0: 0]
>   t0: 1000: 54673752 [0: 0]
> @
>   t*: 1000: 54673752 [0: 0]
>   t0: 1000: 54673752 [0: 0]
> 
> Note: With same steps and commands, HeapProf works on x86 platform; like:
> kuii at ubuntu:~/mem/jemalloc/mytest$ MALLOC_CONF=prof:true,lg_prof_sample:0,prof_final:true LD_PRELOAD=/home/kuii/mem/jemalloc/jemalloc-4.2.1/lib/libjemalloc.so ./test
> kuii at ubuntu:~/mem/jemalloc/mytest$ cat jeprof.23836.0.f.heap
> heap_v2/1
>   t*: 10: 47112 [0: 0]
>   t0: 10: 47112 [0: 0]
> @ 0x7fa08cb98c2d 0x7fa08cb91a1d 0x7fa08cb5d171 0x7fa08cb5d3da 0x7fa08cb5d651 0x40054c 0x400573 0x7fa08c7b0ec5 0x400469
>   t*: 10: 47112 [0: 0]
>   t0: 10: 47112 [0: 0]

A few months ago I tracked down the cause of a similar report, and it turned out to be due to a bug in libgcc on ARM.  Try libunwind (--enable-prof-libunwind).

Jason