Date: Sat, 19 Mar 2016 05:22:16 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r297039 - head/sys/x86/x86 Message-ID: <20160319032216.GZ1741@kib.kiev.ua> In-Reply-To: <201603181948.u2IJmndg063765@repo.freebsd.org> References: <201603181948.u2IJmndg063765@repo.freebsd.org>
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On Fri, Mar 18, 2016 at 07:48:49PM +0000, John Baldwin wrote:
>
> - for (x = 0; x < delay; x += 5) {
> + for (x = 0; x < delay; x++) {
> if ((lapic_read_icr_lo() & APIC_DELSTAT_MASK) ==
> APIC_DELSTAT_IDLE)
> return (1);
> - DELAY(5);
> + DELAY(1);
> }
> return (0);
> }
Ideally we would structure the loop differently. I think it is more
efficient WRT latency to only block execution by ia32_pause(), and
compare the the getbinuptime() results to calculate spent time, on each
loop step.
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