Ildus Kurbangaliev <i.kurbangal...@postgrespro.ru> writes: > I made benchmark of gettimeofday(). I believe it is certainly usable for > monitoring. > Testing configuration: > 24 cores, Intel Xeon CPU X5675@3.07Ghz > RAM 24 GB
> 54179703 - microseconds total > 2147483647 - (INT_MAX), the number of gettimeofday() calls > >>> 54179703 / 2147483647.0 > 0.025229390256679331 > Here we have the average duration of one gettimeofday in microseconds. 25 nsec per gettimeofday() is in the same ballpark as what I measured on a new-ish machine last year: http://www.postgresql.org/message-id/flat/31856.1400021...@sss.pgh.pa.us The problem is that (a) on modern hardware that is not a small number, it's the equivalent of 100 or more instructions; and (b) the results look very much worse on less-modern hardware, particularly machines where gettimeofday requires a kernel call. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
