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Date:      Fri, 15 Nov 2002 02:04:21 +1100 (EST)
From:      Bruce Evans <bde@zeta.org.au>
To:        Borja Marcos <borjam@sarenet.es>
Cc:        Borja Marcos <borjamar@sarenet.es>, <freebsd-current@FreeBSD.ORG>
Subject:   Re: MORE: Re: Bug? vm.stats.sys.v_syscall not updated
Message-ID:  <20021115015646.K10490-100000@gamplex.bde.org>
In-Reply-To: <200211140050.44760.borjam@sarenet.es>

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On Thu, 14 Nov 2002, Borja Marcos wrote:

> 	Looking at the kernel sources, I see that in /usr/src/sys/i386/i386/trap.c,
>
> --- snip
>
>     /*
>      * note: PCPU_LAZY_INC() can only be used if we can afford
>      * occassional inaccuracy in the count.
>      */
>     PCPU_LAZY_INC(cnt.v_syscall);
>
> --- snip
>
> 	This seems to be a macro to update a per-CPU variable. But, AFAIK, there is
> *only* one variable now. Is it correct?
>
> 	The ia64 version (/usr/src/sys/ia64/ia64) happily updates this variable:
> ...

This part is a bug in the ia64 version (in fact, in all non-i386 arches for
syscall() and in all arches for many other statistics): PCPU_LAZY_INC() is
only deployed for 1 variable on 1 arch so far.  (See an earlier reply for
how to unbreak the deployed case.)

Bruce


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