( ESNUG 348 Item 11 ) -------------------------------------------- [3/30/00]
Subject: ( ESNUG 346 #6 ) DC 99.10-04 report_power Memory Leak & DW Libs
> We are using DC 99.10-04 in the Tcl mode and the report_power command for
> power characterization of DW-components for a LSI library. The power
> characterization requires several calls of the report_power command. We
> have found that report_power does not de-allocate memory which leads to a
> program abortion for larger characterization runs.
>
> I have attached a simple DC test script to demonstrate the problem.
>
> # program to demonstrate memory leak produced by report_power
>
> # create module from designware-library
>
> elaborate DW02_mult -arch csa -lib DW02 -update \
> -param "A_width = 4, B_width = 4 "
> current_design
> compile -map_effort medium
> ungroup -all -flatten
> change_names -rules vhdl -hier
>
> # calculate power
> while { 1 == 1 } {
> set_switching_activity -period 10 -toggle_rate 0.7 [all_nets]
> report_power }
>
> One should start the script and observe the memory requirement to see
> that already for this small component each report_power command requires
> some more Mbytes of additional memory.
>
> - Gerd Jochens
> OFFIS Research Institute Oldenburg, Germany
From: Gerd Jochens <Jochens@OFFIS.de>
Dear John,
Thought I'd follow up on this. The application manager of Synopsys Germany
responded after my letter ran in ESNUG. He said that the settings of the
synthetic_library & link_library variables are responsible for this.
Our default setting of these variables are to include all available DW
libraries (set link_library [list {*} {lcbg10p_wccomv.db} dw01.sldb
dw02.sldb dw03.sldb dw04.sldb dw05.sldb dw07.sldb]). This setting forces
the memory leak to occur.
I have found that reducing the number of link libraries to only dw01 and
dw02 (for example) avoids the problem. Which library or combination of
libraries is responsible for the leak is still not clear.
So, my advice for the moment is to include only those libraries which are
really necessary for a certain design.
- Gerd Jochens
OFFIS Research Institute Oldenburg, Germany
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