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Re: WPA stream_out form & memory consumption
- From: Jan Hubicka <hubicka at ucw dot cz>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: Martin Liška <mliska at suse dot cz>, Jan Hubicka <hubicka at ucw dot cz>, GCC Development <gcc at gcc dot gnu dot org>
- Date: Mon, 7 Apr 2014 20:20:34 +0200
- Subject: Re: WPA stream_out form & memory consumption
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- References: <53286192 dot 3030600 at suse dot cz> <20140325205021 dot GA6581 at atrey dot karlin dot mff dot cuni dot cz> <5333E6B8 dot 3000504 at suse dot cz> <5333F3D3 dot 1010009 at suse dot cz> <533C1B04 dot 40407 at suse dot cz> <20140402224344 dot GB1359 at atrey dot karlin dot mff dot cuni dot cz> <533D6FF7 dot 1030009 at suse dot cz> <20140403204013 dot GA16291 at kam dot mff dot cuni dot cz> <53428B1F dot 5050107 at suse dot cz> <CAFiYyc3v-0duCwv8e0twUHhDD56M1PtsQo5bJLaZmCzmVO0LBQ at mail dot gmail dot com>
> AFAIK we settled on a simpler one dropping columns at stream-out time
> that also helped.
> As for the correct way to do the optimization we agreed(?) that streaming
> the locations elsewhere and using references to them is more appropriate.
> At stream-in (or before stream-out) we can then read the location pairs
> and sort them before assigning linemap entries.
Yep, however what makes difference is the sharing in between compilation units
(so sameheaders gets assigned same locations) rather than sharing within the unit
(by my experiments). The separate streaming+sorting will only help sharing
within the unit.
Perhaps something rather simplelike keeping previous stream and merging them will
work, too, not sure if better than the simple cache hash though.
Or perhaps we can somehow track per-source-file location spaces. Don't know.