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From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Cc: mtosatti@redhat.com, kvm@vger.kernel.org
Subject: Re: [RFC kvm-unit-tests] api: Add dirty logging performance test
Date: Sun, 08 Jan 2012 16:54:27 +0200	[thread overview]
Message-ID: <4F09AE23.5070101@redhat.com> (raw)
In-Reply-To: <20120108234925.f3cd34c9ead6ad9c3e07b980@gmail.com>

On 01/08/2012 04:49 PM, Takuya Yoshikawa wrote:
> > > +
> > > +        gettimeofday(&start_time, NULL);
> > > +        slot.update_dirty_log();
> > > +        gettimeofday(&end_time, NULL);
> > 
> > Nicer to have a function that returns time in nanoseconds.
>
> I don't know such an API which can be used in userspace.

static uint64_t time_ns()
{
    struct timeval tv;

    gettimeofday(&tv, NULL);
    return tv.tv_sec * (uint64_t)1000000000 + tv.tv_usec * 1000;
}

(that's not nanosecond precision, but it gives a single number instead
of a pair; there's also clock_gettime() that does have nanosecond
precision).
> If we can use nano-precision timer, I want to check other things
> too, e.g. emulation.
>

-- 
error compiling committee.c: too many arguments to function


      reply	other threads:[~2012-01-08 14:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-08 13:58 [RFC kvm-unit-tests] api: Add dirty logging performance test Takuya Yoshikawa
2012-01-08 14:21 ` Avi Kivity
2012-01-08 14:49   ` Takuya Yoshikawa
2012-01-08 14:54     ` Avi Kivity [this message]

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