Re: [Iverilog-devel] More vec4-stack progress

[Stephen W. <st...@ic...>]

OK, that's interesting. I theorize that what is going on here
is that with the vec4-stack branch there are more vvp_vector4_t
instances running around, and since they allocate some memory to
hold the bit values there is a lot of allocation overhead.
The way to address that may be to use a custom allocator within
the vvp_vector4_t to allocate the bit space.

Given that it is running faster then "master" even with the
increased memory, I'm willing to accept the cost for now, and
put it off until after the Big Merge.

On 12/05/2014 12:38 PM, Martin Whitaker wrote:
> Memory use is reported by 'vvp -v'. With the master branch, I get
> 
> Compiling VVP ...
>   ... VVP file version 0.10.0 (devel) (s20121218-480-g020e280-dirty)
> Compile cleanup...
>   ... Linking
>   ... Removing symbol tables
>   ... Compiletf functions
>   ...     9343 functors (net_fun pool=786432 bytes)
>                 2807 logic
>                    0 bufif
>                    0 resolv
>                 2181 signals
>   ...     8707 filters (net_fil pool=1310720 bytes)
>   ...    44817 opcodes (1081344 bytes)
>   ...     5474 nets
>   ...     9343 vvp_nets (1048544 bytes)
>   ...       12 arrays (129 words)
>   ...      125 memories
>                  125 logic (277608 words)
>                    0 real (0 words)
>   ...      407 scopes
>   ... 0.167 seconds, 59244.0/17172.0/2052.0 KBytes size/rss/shared
> Running ...
>   ...execute EndOfCompile callbacks
>   ...propagate initialization events
>   ...execute StartOfSim callbacks
>   ...run scheduler
> Generating expected results
> Running test
>   ...execute Postsim callbacks
>   ... 59.719 seconds, 261020.0/219492.0/2344.0 KBytes size/rss/shared
> Event counts:
>        130139 time steps (pool=128)
>       2411954 thread schedule events
>      23563521 assign events
>               ...assign(vec4) pool=18724
>               ...assign(vec8) pool=204
>               ...assign(real) pool=256
>               ...assign(word) pool=128
>               ...assign(word/r) pool=204
>       9721848 other events (pool=4096)
> 
> With the vec4-stack branch, the only differences are:
> 
>   ...    45991 opcodes (1105920 bytes)
> 
>   ... 0.17 seconds, 60368.0/18228.0/2044.0 KBytes size/rss/shared
> 
>   ... 55.939 seconds, 555040.0/513392.0/2356.0 KBytes size/rss/shared
> 
> 
> Stephen Williams wrote:
>>
>> Those are pretty encouraging results.
>>
>> What are you looking at for the memory use?
>>
>> On 12/05/2014 12:06 PM, Martin Whitaker wrote:
>>> Time taken for my long sequence of short tests:
>>>
>>>     master      22:48
>>>     vec4-stack  18:28
>>>
>>> Time taken for my short sequence of longer tests:
>>>
>>>     master     (lossless)  12:12
>>>     vec4-stack (lossless)   9:53
>>>
>>>     master     (strict)    11:49
>>>     vec4-stack (strict)     9:35
>>>
>>> So performance looks good. Memory use is still a bit of a concern - for the
>>> particular test I looked at, vvp reported
>>>
>>>     master      261,016 KB
>>>     vec4-stack  554,984 KB
>>>


-- 
Steve Williams                "The woods are lovely, dark and deep.
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