Date: Tue, 25 Sep 2007 17:28:37 +0400 From: "Artem Kuchin" <matrix@itlegion.ru> To: <freebsd-stable@FreeBSD.ORG>, <matrix@itlegion.ru> Subject: Re: device polling and weird timer interrupt count from vmstat Message-ID: <022e01c7ff77$fc68b4a0$0c00a8c0@Artem> References: <200709251257.l8PCvuZ8001535@lurza.secnetix.de>
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>> 3) Is timer int really generated on each cpu? Am i really wasting cpu >> time on ~4000 ints per second? > > 4000 ints per second is rather nothing on any modern CPU. > Have a look at the top(1) display of an otherwise idle > system. The "%interrupt" column should be zero, even if > it's processing 4000 timer interrupts per second. As far > as I know, the cpu timer interrupt handler is very light- > weight. Thank you for the answer. My convern is that with 4 CPUs i get 8000 ints/second. While em generates only about 200 ints/second. As i undertand not all int handlers are the same. Some are heavy and some are light on CPU. So, the question is what is better (better=less CPU time): 8000 ints/sec from timer or 200 ints/sec from NIC? -- Regards, Artem
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