performance degradation on kernel upgrade (due to commit ab0a9735e06914ce4d2a94ffa41497dbc142fe7f)

From: Jagdish Motwani
Date: Fri Sep 21 2012 - 09:49:40 EST


Recently i upgraded my kernel from 2.6.29.6 to 2.6.35.14.

After upgrading i got very poor performance on my postgre database.


My test.sql contains 10000 postgre insert query


Linux 2.6.29.6

time psql -U user -d database -f test.sql > /dev/null
real 0m 7.23s
user 0m 0.38s
sys 0m 0.12s



Linux 2.6.35.14

# time psql -U user -d database -f test.sql > /dev/null
real 1m 4.05s
user 0m 0.44s
sys 0m 0.12

I even tried Linux 3.5.4 and got similar results.

Using git bisect, i got commit ab0a9735e06914ce4d2a94ffa41497dbc142fe7f

Is it a behavior change or am i missing something? Are there any workarounds for this?


Regards,
Jagdish Motwan
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