2011/3/25 DM <dm.a...@gmail.com>: > gettimeofday() on my new box is slow, after further research we found that, > when we set ACPI=Off, we got a good clock performance even the explain > analyze gave approximately gave the right values, but the hyperthreading is > off.
Disabling ACPI also disables most CPU power management, so that explains why you get a stable TSC that way. But that's not a real fix. > could you guide me how to set, the parameter current_clocksource to TSC, You can't "set" it, the kernel will automatically choose TSC, if it's stable, at boot time; see messages in dmesg. A better way to disable power management on CentOS is to disable the 'cpuspeed' service. Note that this is not necessary for newer CPUs; Intel Nehalem and AMD Phenom series have a stable TSC even with power management enabled. Regards, Marti -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
