From: "Ilpo Järvinen" <ilpo.jarvinen-pxSi+dnQzZMxHbG02/KK1g@public.gmane.org> To: Arnaldo Carvalho de Melo <acme-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Cc: dwarves-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: speedup in tag lookup using hash tables Date: Tue, 12 Feb 2008 13:24:44 +0200 (EET) Message-ID: <Pine.LNX.firstname.lastname@example.org> (raw) In-Reply-To: <20080212000310.GB4157-f8uhVLnGfZaxAyOMLChx1axOck334EZe@public.gmane.org> On Mon, 11 Feb 2008, Arnaldo Carvalho de Melo wrote: > Today I optimized the dwarves a bit by using a per object file > hash table for tag lookup, it yelded almost 50% speedup on pahole when > running on a vmlinux file :-) > > codiff doesn't makes that much tag lookups, so we didn't got > much improvements there, Because I had to do these file by file anyway, I ended up using modified timestamps in my scripts to avoid loading .o files altogether when one wasn't recompiled. It helped some. > but I'm doing experiments on dead tag elimination > that probably will help a lot there, but for that I have first to grok > Ulrich Drepper's libdisasm to find out what are the tags that are really > used by looking at accesses to register indexed memory areas that use as > a base pointer what is in local/global variables and function > parameters. > > This also will provide the basis for detecting access patterns > that will ultimatelly allow libdwarves_reorganize to do struct > reorganizations to improve locality of reference, etc. This sounds nice, I was thinking something similar earlier but would have tried to do that with some kind of source analysis. > Please take a look at v1.6 that I pushed today and tell me your > impressions. Thanks, I'll check that later on. My bruteforce inline remover run over all include/ stuff just finished yesterday after ~1.5 days (ie. ~5800 inlines compile tested on ~90 slaves, next time I'll have to plug ccache into that site-specific distribute thing I use to speed it up a lot :-)), I'll post the results later on to lkml+netdev with some patches and thoughts, the winner seems to be this beauty :-) : -110805 869 funcs, 198 +, 111003 -, diff: -110805 --- skb_put ...And 22 other are in 10000+ category and 235 1kB+ (some overlap exists due to __-funcs). What still remains to do are the non-include/ headers which might reveal some candies too. -- i.
next prev parent reply index Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-02-12 0:03 Arnaldo Carvalho de Melo [not found] ` <20080212000310.GB4157-f8uhVLnGfZaxAyOMLChx1axOck334EZe@public.gmane.org> 2008-02-12 11:24 ` Ilpo Järvinen [this message] [not found] ` <Pine.LNX.4.64.0802121301180.31652-Y/UOj9v5BLQhZigby9b+C6cUovnZ0M2TMR2xtNvyitY@public.gmane.org> 2008-02-12 12:50 ` Arnaldo Carvalho de Melo [not found] ` <20080212125037.GE4157-f8uhVLnGfZaxAyOMLChx1axOck334EZe@public.gmane.org> 2008-02-12 13:24 ` Ilpo Järvinen
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