From owner-freebsd-smp  Thu Apr  4 13:51: 2 2002
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Date: Thu, 4 Apr 2002 13:50:57 -0800 (PST)
From: Matthew Dillon <dillon@apollo.backplane.com>
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To: Jake Burkholder <jake@locore.ca>, John Baldwin <jhb@FreeBSD.ORG>,
	freebsd-smp@FreeBSD.ORG
Subject: per-cpu stats counter support comitted.
References: <XFMail.20020329171752.jhb@FreeBSD.org> <200203292305.g2TN5nX75021@apollo.backplane.com> <20020330001929.H40695@locore.ca> <200203301920.g2UJKxL80198@apollo.backplane.com>
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X-Loop: FreeBSD.org

    Ok guys, I've comitted the work.  This combined with the commit Bruce
    just made to the userret()/ast() code removes all memory/cache stalls
    from the syscall critical path.

    two-process getuid() tests, SMP build:

					per-process
					getuid()/sec

    ++cnt.v_syscall			 853000
    PCPU_LAZY_INC(cnt.v_syscall)	1000000		+17.2%
    PCPU + Bruce's userret() code	1238216		+23.8%

    Total boost: +45%.  This is a significant improvement, folks!

    In anycase, please feel free to convert other vmeter counters from
    atomic_add_int() to PCPU_LAZY_INC().  Remember, not all counters can
    be converted... things like cnt.v_free_min, for example, cannot be
    converted because the VM system needs to get at the value quickly.
    Check before you change.

    We should probably split out the statistics that cannot be made
    per-cpu.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>

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