On 10/11/2012 03:49 PM, Ehsan Akhgari wrote:
Don't both of these proposals map to tons of manual work? I'm not convinced that doing either of those would necessarily be easier than finding and fixing the PGO bug at hand.
The problem is that fixing this one bug might take only a few days, but that underestimates the true cost of PGO. The fact is that, as long as we have it turned on, PGO will keep introducing new bugs. Each new line of code that we write gives PGO an opportunity to miscompile it. This represents an unbounded amount of work for us. This can be compared to the benefits PGO provides, which are growing very slowly, if at all (about 2% per year [1]).
Additionally, I don't think we have a good idea of how many bugs are caused by GCC PGO. Windows PGO issues often turn into topcrashes. On Linux, we may not have enough users for these bugs to bubble up far enough for us to investigate them.
-Bill [1] http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.29.434 _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
