From: Paolo Bonzini <pbonzini@redhat.com>
To: Christopher Covington <cov@codeaurora.org>
Cc: Aaron Lindsay <alindsay@codeaurora.org>,
Peter Maydell <peter.maydell@linaro.org>,
qemu-trivial@nongnu.org,
Peter Crosthwaite <crosthwaite.peter@gmail.com>,
qemu-devel@nongnu.org,
Alistair Francis <alistair.francis@xilinx.com>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [Qemu-devel] [PATCH] Rename cpu_get_icount_{locked,biased}
Date: Wed, 10 Feb 2016 15:13:21 +0100 [thread overview]
Message-ID: <56BB4581.5010508@redhat.com> (raw)
In-Reply-To: <1455113192-27139-1-git-send-email-cov@codeaurora.org>
On 10/02/2016 15:06, Christopher Covington wrote:
> The function does not provide locking but rather adds a bias value.
"Locked" means that you need to take a look outside its call; see how
cpu_get_icount() uses it.
Basically the idea is that a "_locked" in the name warns you to pay
attention. :)
Paolo
> Signed-off-by: Christopher Covington <cov@codeaurora.org>
> ---
> cpus.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 898426c..50403c4 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -164,7 +164,7 @@ int64_t cpu_get_icount_raw(void)
> }
>
> /* Return the virtual CPU time, based on the instruction counter. */
> -static int64_t cpu_get_icount_locked(void)
> +static int64_t cpu_get_icount_biased(void)
> {
> int64_t icount = cpu_get_icount_raw();
> return timers_state.qemu_icount_bias + cpu_icount_to_ns(icount);
> @@ -177,7 +177,7 @@ int64_t cpu_get_icount(void)
>
> do {
> start = seqlock_read_begin(&timers_state.vm_clock_seqlock);
> - icount = cpu_get_icount_locked();
> + icount = cpu_get_icount_biased();
> } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start));
>
> return icount;
> @@ -293,7 +293,7 @@ static void icount_adjust(void)
>
> seqlock_write_lock(&timers_state.vm_clock_seqlock);
> cur_time = cpu_get_clock_locked();
> - cur_icount = cpu_get_icount_locked();
> + cur_icount = cpu_get_icount_biased();
>
> delta = cur_icount - cur_time;
> /* FIXME: This is a very crude algorithm, somewhat prone to oscillation. */
> @@ -356,7 +356,7 @@ static void icount_warp_rt(void)
> * In adaptive mode, do not let QEMU_CLOCK_VIRTUAL run too
> * far ahead of real time.
> */
> - int64_t cur_icount = cpu_get_icount_locked();
> + int64_t cur_icount = cpu_get_icount_biased();
> int64_t delta = clock - cur_icount;
> warp_delta = MIN(warp_delta, delta);
> }
>
prev parent reply other threads:[~2016-02-10 14:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-10 14:06 [Qemu-devel] [PATCH] Rename cpu_get_icount_{locked,biased} Christopher Covington
2016-02-10 14:13 ` Paolo Bonzini [this message]
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