From: Peter Maydell <peter.maydell@linaro.org>
To: Xin Tong <xerox.time.tech@gmail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] QEMU TB Unlinking due to interrupt.
Date: Fri, 9 Dec 2011 23:45:09 +0000 [thread overview]
Message-ID: <CAFEAcA8ddbNsioDs3WFAGhzFt5yTyGS33K0Knx31oXJcP5Bsfg@mail.gmail.com> (raw)
In-Reply-To: <CALKntY3NyrNVjb7XSXxvrGwj5VKZNbLp6AChHk+2GdjJUom72A@mail.gmail.com>
On 9 December 2011 18:44, Xin Tong <xerox.time.tech@gmail.com> wrote:
> Currently, QEMU unchains TBs if there is an interrupt pending. I would
> like to know whether there is any reason behind this ? (why not
> checking interrupt status in the beginning of every tb ?)
The theory is that it's faster overall to do a slightly slow
operation (tb unlinking) on interrupts rather than do a check
at the beginning of every tb (happens a lot in the normal
code path).
However the tb unlinking code is racy and personally I think
we should get rid of it in favour of a simpler scheme like a
flag check. I have some prototype patches kicking around for
this.
-- PMM
next prev parent reply other threads:[~2011-12-09 23:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-09 18:44 [Qemu-devel] QEMU TB Unlinking due to interrupt Xin Tong
2011-12-09 23:45 ` Peter Maydell [this message]
2011-12-10 0:08 ` Xin Tong
2011-12-13 8:10 ` 陳韋任
2011-12-14 1:29 ` Xin Tong
2011-12-14 14:29 ` 陳韋任
2012-01-20 7:41 ` 陳韋任
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAFEAcA8ddbNsioDs3WFAGhzFt5yTyGS33K0Knx31oXJcP5Bsfg@mail.gmail.com \
--to=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=xerox.time.tech@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).