From: Andi Kleen <andi@firstfloor.org>
To: imipak@yahoo.com
Cc: netdev@vger.kernel.org, Daniel Ng <daniel_ng11@lycos.com>
Subject: Re: Multicast Routing Kernel option?
Date: Fri, 15 Aug 2008 16:13:24 +0200 [thread overview]
Message-ID: <87tzdmxt6j.fsf@basil.nowhere.org> (raw)
In-Reply-To: <124178.76775.qm@web31502.mail.mud.yahoo.com> (Jonathan Day's message of "Fri, 15 Aug 2008 01:41:51 -0700 (PDT)")
Jonathan Day <imipak@yahoo.com> writes:
> They could, I guess, but context switches are expensive (think 20ms
> from kernel to user, and same in reverse)
40ms for a system call? That would be really horrible if it really
were that slow. Fortunately it's not. A Core2 (Merom) here can do a
very simple system call roundtrip (getppid()) in ~570 cycles, that is
at 2Ghz less than 300ns. You are roughly 5 orders of magnitude off.
-Andi
prev parent reply other threads:[~2008-08-15 14:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-15 7:37 Multicast Routing Kernel option? Daniel Ng
2008-08-15 8:41 ` Jonathan Day
2008-08-15 14:13 ` Andi Kleen [this message]
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