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

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

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OK, that's very useful feedback. Given that, and assuming no other
complaints, I will merge the vec4-stack branch into git master tomorrow,
Saturday, 6 Dec. in the morning.

In the mean time, I've made a 20141205 snapshot available in the
usual FTP download site. That is the last snapshot before the big
merge.


On 12/05/2014 01:12 PM, Martin Whitaker wrote:
> I've tracked down the construct that is causing the problem - it's
> a user function call in a continuous assignment statement. Looks
> like there's a memory leak there. The leak is present in the master
> branch as well. I've got a simple test case that exposes the
> problem, so I'll work on a fix. I'll wait until after the Big Merge
> before I push anything!
> 
> Stephen Williams wrote:
>> 
>> 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
>>>>> 
>> 
>> 
> 
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- -- 
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
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