Re: [Valgrind-users] Expected slowdown

[Christoph B. <bar...@or...>]

Am Dienstag, 24. Oktober 2006 15:55 schrieb Julian Seward:
> > CPU: AMD64 processors, speed 2605.94 MHz (estimated)
> > Counted CPU_CLK_UNHALTED events (Cycles outside of halt state) with a
> > unit mask of 0x00 (No unit mask) count 100000
> > samples  %        symbol name
> > 11007731 91.2732  vgPlain_record_ExeContext
>
> Gaaah!  If that's true it is really bad.  What is the inner loop
> of your application doing?

I would not say that it does something weird. Here is a basic outline of the 
inner loop that gets a binary tree as input:

while (tree.has_leaf()) {
	for each (buffer/inverter)
		check_merge_timing(leaf, leaf->parent)
}
for 2401 possibilites
	check_root_connect	
       
check_merge_timing and check_root_connect are functions that spend 95% of 
their time in extracting function approximations from a 2-dim lookup table.


Here is the exact count of malloc/free after 19hours in valgrind:
==00:19:53:01.364 9133== malloc/free: 98,138,916 allocs, 97,052,020 frees, 
18,848,731,867 bytes allocated.
The run has been killed with STRG+C


And finally an oprofile output during the initialization phase of the 
application:

Counted CPU_CLK_UNHALTED events (Cycles outside
warning: /boot/vmlinux-2.6.13-15.12-smp.gz is n
samples  %        symbol name
7836011  41.8869  (no symbols)
1049427   5.6096  vgPlain_arena_free
758054    4.0521  (no symbols)
722585    3.8625  set_address_range_perms
687323    3.6740  vgMemCheck_helperc_LOADV64le
665990    3.5600  vgMemCheck_helperc_STOREV64le
663955    3.5491  vgModuleLocal_search_one_cfit
584375    3.1237  vgPlain_run_innerloop__dispat
519607    2.7775  vgMemCheck_helperc_MAKE_STACK
476431    2.5467  doRegisterAllocation
297077    1.5880  mc_new_mem_stack_8
274416    1.4669  mc_die_mem_stack_8
241299    1.2898  vgMemCheck_helperc_STOREV8
238227    1.2734  vgPlain_unknown_SP_update
229308    1.2258  (no symbols)
206303    1.1028  unlinkBlock
197175    1.0540  vgPlain_use_CF_info
188233    1.0062  vgPlain_arena_malloc
160315    0.8570  mc_expensive_sanity_check
150404    0.8040  vgMemCheck_helperc_LOADV8
140847    0.7529  vgMemCheck_check_mem_is_noacc
132725    0.7095  vgPlain_scheduler
113339    0.6058  vgPlain_search_transtab
97279     0.5200  (no symbols)
94171     0.5034  get_secmap_ptr
93965     0.5023  vgPlain_record_ExeContext
88662     0.4739  vgMemCheck_helperc_LOADV32le
81197     0.4340  amd64g_calculate_rflags_all_W
69063     0.3692  vgPlain_run_innerloop
64332     0.3439  mkInuseBlock
57323     0.3064  vgPlain_free
53945     0.2884  blockSane
53554     0.2863  arenaId_to_ArenaP
49555     0.2649  vgMemCheck_helperc_STOREV32le

The image name for the first symbol is
anon (tgid:15483 range:0x4029a5000-0x40f2f2000)
and for the second
anon (tgid:15483 range:0x4029a5000-0x41243c000)

One can see that during initialization the application seems to behave 
normally. 

Christoph Bartoschek