[Valgrind-users] valgrind prefetch instructions not supported

[<ar...@de...>]

It seems like valgrind isn't supporting prefetch instructions. When I
add -fprefetch-loop-arrays to gcc valgrind doesn't work anymore:

aroldan@volatile:~$ gcc -march=athlon -O3 -fomit-frame-pointer -ffast-math -funroll-loops -Wall -pipe -s demuxtest.c -o demuxtest
demuxtest.c: I funktion `demuxbuff2':
demuxtest.c:159: varning: `baseadr' might be used uninitialized in this function
demuxtest.c:160: varning: `index' might be used uninitialized in this function
demuxtest.c:161: varning: `ce' might be used uninitialized in this function
demuxtest.c: På toppnivå:
demuxtest.c:117: varning: `demuxbuff' defined but not used
aroldan@volatile:~$ valgrind -v ./demuxtest                       
==20153== Memcheck, a.k.a. Valgrind, a memory error detector for x86-linux.
==20153== Copyright (C) 2002-2003, and GNU GPL'd, by Julian Seward.
==20153== Using valgrind-2.0.0, a program supervision framework for x86-linux.
==20153== Copyright (C) 2000-2003, and GNU GPL'd, by Julian Seward.
==20153== Command line:
==20153==    ./demuxtest
==20153== Startup, with flags:
==20153==    --suppressions=/usr/lib/valgrind/default.supp
==20153==    -v
==20153== Reading syms from /home/aroldan/demuxtest
==20153==    object doesn't have a symbol table
==20153==    object doesn't have any debug info
==20153== Reading syms from /lib/ld-2.3.2.so
==20153==    object doesn't have a symbol table
==20153==    object doesn't have any debug info
==20153== Reading syms from /usr/lib/valgrind/vgskin_memcheck.so
==20153== Reading syms from /usr/lib/valgrind/valgrind.so
==20153== Reading syms from /lib/libc-2.3.2.so
==20153==    object doesn't have a symbol table
==20153==    object doesn't have any debug info
==20153== Reading suppressions file: /usr/lib/valgrind/default.supp
==20153== Estimated CPU clock rate is 809 MHz
==20153== 
204800 kbyte rx buffers processed in 8981761 microseconds
Demuxed 124.528037Mbit/s
==20153== 
==20153== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
==20153== malloc/free: in use at exit: 0 bytes in 0 blocks.
==20153== malloc/free: 6 allocs, 6 frees, 6291464 bytes allocated.
==20153== 
--20153--     TT/TC: 0 tc sectors discarded.
--20153--            591 chainings, 0 unchainings.
--20153-- translate: new     1103 (17741 -> 233370; ratio 131:10)
--20153--            discard 0 (0 -> 0; ratio 0:10).
--20153--  dispatch: 101100000 jumps (bb entries), of which 3908 (0%) were uncha
ined.
--20153--            2024/3148 major/minor sched events.  1104 tt_fast misses.
--20153-- reg-alloc: 181 t-req-spill, 44275+1225 orig+spill uis, 5581 total-reg-
r.
--20153--    sanity: 2025 cheap, 81 expensive checks.
--20153--    ccalls: 4163 C calls, 56% saves+restores avoided (13788 bytes)
--20153--            5500 args, avg 0.87 setup instrs each (1422 bytes)
--20153--            0% clear the stack (12489 bytes)
--20153--            1705 retvals, 32% of reg-reg movs avoided (1074 bytes)
aroldan@volatile:~$ gcc -march=athlon -O3 -fomit-frame-pointer -ffast-math -funroll-loops -fprefetch-loop-arrays -Wall -pipe -s demuxtest.c -o demuxtest
demuxtest.c: I funktion `demuxbuff2':
demuxtest.c:159: varning: `baseadr' might be used uninitialized in this function
demuxtest.c:160: varning: `index' might be used uninitialized in this function
demuxtest.c:161: varning: `ce' might be used uninitialized in this function
demuxtest.c: På toppnivå:
demuxtest.c:117: varning: `demuxbuff' defined but not used
aroldan@volatile:~$ ./demuxtest                       
204800 kbyte rx buffers processed in 1288141 microseconds
Demuxed 868.290868Mbit/s
aroldan@volatile:~$ valgrind -v ./demuxtest                       
==20171== Memcheck, a.k.a. Valgrind, a memory error detector for x86-linux.
==20171== Copyright (C) 2002-2003, and GNU GPL'd, by Julian Seward.
==20171== Using valgrind-2.0.0, a program supervision framework for x86-linux.
==20171== Copyright (C) 2000-2003, and GNU GPL'd, by Julian Seward.
==20171== Command line:
==20171==    ./demuxtest
==20171== Startup, with flags:
==20171==    --suppressions=/usr/lib/valgrind/default.supp
==20171==    -v
==20171== Reading syms from /home/aroldan/demuxtest
==20171==    object doesn't have a symbol table
==20171==    object doesn't have any debug info
==20171== Reading syms from /lib/ld-2.3.2.so
==20171==    object doesn't have a symbol table
==20171==    object doesn't have any debug info
==20171== Reading syms from /usr/lib/valgrind/vgskin_memcheck.so
==20171== Reading syms from /usr/lib/valgrind/valgrind.so
==20171== Reading syms from /lib/libc-2.3.2.so
==20171==    object doesn't have a symbol table
==20171==    object doesn't have any debug info
==20171== Reading suppressions file: /usr/lib/valgrind/default.supp
==20171== Estimated CPU clock rate is 814 MHz
==20171== 
disInstr: unhandled instruction bytes: 0xF 0xD 0xD 0xAC
Illegal instruction
aroldan@volatile:~$ 

-- 
Andres Roldan

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