Re: Latency test

Paolo Mantegazza <[email protected]> Fri, 9 Mar 2018 09:07:47 +0100
Newsgroups	gmane.linux.real-time.rtai
Message-ID	<[email protected]>
This is a multi-part message in MIME format.
--===============5912241993883873429==
Content-Type: multipart/alternative;
 boundary="------------1891C745A413D4C639408486"
Content-Language: en-US

This is a multi-part message in MIME format.
--------------1891C745A413D4C639408486
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: quoted-printable

That fix has nothing to do with latencies. From the little I know, it=20
simply cares of the fact that on recent Intel cpus any address fault.=20
between kerne-user space, must happen in a precise place of the code=20
(copy to-from) while, before,=C2=A0 the stack was shared between those sp=
aces=20
before and RTAi exploited such a feature.

Paolo.

On 03/09/2018 03:56 AM, Alec Ari wrote:
> I thought the overruns were fixed with the new syscall modifications=20
> (USE_STACK_ARGS) Maybe it only affects newer kernels.. Can you try the=20
> 4.9 kernel patch?
>
> Alec Ari
>
>
> _______________________________________________
> Rtai mailing list
> [email protected]
> https://mail.rtai.org/cgi-bin/mailman/listinfo/rtai



--------------1891C745A413D4C639408486
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable

<html>
  <head>
    <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dutf=
-8">
  </head>
  <body text=3D"#000000" bgcolor=3D"#FFFFFF">
    <div class=3D"moz-cite-prefix">That fix has nothing to do with
      latencies. From the little I know, it simply cares of the fact
      that on recent Intel cpus any address fault. between kerne-user
      space, must happen in a precise place of the code (copy to-from)=C2=
=A0
      while, before,=C2=A0 the stack was shared between those spaces befo=
re
      and RTAi exploited such a feature. <br>
      <br>
      Paolo.<br>
      <br>
      On 03/09/2018 03:56 AM, Alec Ari wrote:<br>
    </div>
    <blockquote type=3D"cite"
      cite=3D"mid:[email protected]">
      <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Du=
tf-8">
      <div style=3D"font-family:times new roman, new york, times,
        serif;font-size:16px;">
        <div>I thought the overruns were fixed with the new syscall
          modifications (USE_STACK_ARGS) Maybe it only affects newer
          kernels.. Can you try the 4.9 kernel patch?<br>
        </div>
        <div><br>
        </div>
        <div>Alec Ari<br>
        </div>
      </div>
      <br>
      <fieldset class=3D"mimeAttachmentHeader"></fieldset>
      <br>
      <pre wrap=3D"">_______________________________________________
Rtai mailing list
<a class=3D"moz-txt-link-abbreviated" href=3D"mailto:[email protected]">Rtai@=
rtai.org</a>
<a class=3D"moz-txt-link-freetext" href=3D"https://mail.rtai.org/cgi-bin/=
mailman/listinfo/rtai">https://mail.rtai.org/cgi-bin/mailman/listinfo/rta=
i</a></pre>
    </blockquote>
    <p><br>
    </p>
  </body>
</html>

--------------1891C745A413D4C639408486--

--===============5912241993883873429==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
Rtai mailing list
[email protected]
https://mail.rtai.org/cgi-bin/mailman/listinfo/rtai
--===============5912241993883873429==--