[Python-Dev] iterzip() (original) (raw)

Tim Peters tim.one@comcast.net
Mon, 29 Apr 2002 19:42:22 -0400

[Neil Schemenauer]

... I just tried measuring the time spent in the GC while loading some nasty web pages in our system (stuff that looks at thousands of objects). I used the Pentium cycle counter since clock(2) seems to have very low resolution. Setting threshold0 to 7500 makes the GC take up twice the amount of time as with the default settings (700). That surprised me. I thought it wouldn't make much difference. Maybe I screwed up. :-)

Did you try reducing theshold0 too? Maybe GC time tends toward zero as threshold0 does .

I wouldn't discount cache effects here. 7500 objects adds up to lot of bytes, and gc traversal touches stuff all over them. This is one good reason for why a gen0 traversal of the 7500 most-recently allocated still-live objects may take significantly longer than 10 gen0 traversals of the 750 suchlike.