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Re: [PATCH] Add tree rest of compilation timevar
Matt Austern <austern@apple.com> writes:
| On Dec 29, 2004, at 11:36 AM, Andrew Pinski wrote:
|
| >
| > On Dec 29, 2004, at 2:28 PM, Jeffrey A Law wrote:
| >
| >> On Wed, 2004-12-29 at 00:28 -0500, Andrew Pinski wrote:
| >>> As Jeff Law and others have discussed before, we attribute some non
| >>> expand related code to expand. This patch add a new time var for
| >>> tree rest of compilation, just like rest of compilation for RTL
| >>> level.
| >>>
| >>> OK? Bootstrapped and tested on powerpc-darwin.
| >>>
| >>> Thanks,
| >>> Andrew Pinski
| >>>
| >>> ChangeLog:
| >>>
| >>> * timevar.def (TV_TREE_REST): New time var.
| >>> * tree-optimize.c (tree_rest_of_compilation): Use TV_TREE_REST
| >>> instead
| >>> of TV_EXPAND.
| >> All this does is move the problem from one place TV_EXPAND to
| >> TV_TREE_REST -- it does nothing to actually resolve the issues at
| >> hand.
| >> [ ie, TV_TREE_REST gets all the random tree-optimizer stuff plus the
| >> tree->rtl expansion time. ]
| >
| > No it does not get the expansion time because pass_expand has TV_EXPAND
| > as its timevar.
|
| Actually, I've got a more general question: do people find this
| timevar stuff useful in understanding compilation performance? If so,
| what do they find it useful for? If we have a clearer idea of the
| purpose of this feature, we might get some better guidance on how to
| change it.
I believe it is useful for getting a picture at large -- not in
the small. When I see a -ftime-report that indicate 40% in
name-lookup, I guess I should not spend my time looking for the hotspot
in the gimplification stage.
However, it does not give me any clue about why name-lookup is sucking
so much...
-- Gaby