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<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Hi
All,</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=771454605-24112009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Recently came across
an issue which is decribed below.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=771454605-24112009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Setup: Port
Multiplier with 2 HDD's connected to it; Port multiplier is connected to a SATA
port of the Host Controller.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=771454605-24112009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Test: HDD1 is
mounted and using dd command a file of size 512MB is being written on
it.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Command: <SPAN
lang=EN>time sh -c "dd if=/dev/zero of=/mnt/hd/ddfile bs=1k count=512000
&& sync"</SPAN></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009><SPAN
lang=EN></SPAN></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009><SPAN lang=EN>While
this command is running, if the second HDD on PMP is plugged out, the R/W speed
of the first HDD gets affected.</SPAN></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009><SPAN lang=EN>Please
see the results of experiments on 2.6.31 kernel.</SPAN></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009><SPAN
lang=EN></SPAN></SPAN></FONT> </DIV><FONT size=2><SPAN
class=771454605-24112009><SPAN lang=EN>
<DIV>
<TABLE style="WIDTH: 388pt; BORDER-COLLAPSE: collapse" cellSpacing=0
cellPadding=0 width=518 border=0 x:str>
<COLGROUP><FONT face=Arial>
<COL style="WIDTH: 137pt; mso-width-source: userset; mso-width-alt: 6692"
width=183>
<COL style="WIDTH: 141pt; mso-width-source: userset; mso-width-alt: 6875"
width=188>
<COL style="WIDTH: 110pt; mso-width-source: userset; mso-width-alt: 5376"
width=147></FONT>
<TBODY>
<TR style="HEIGHT: 12.75pt" height=17>
<TD class=xl22
style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 137pt; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent"
width=183 height=17><FONT face=Arial size=2><STRONG>Plug
Out</STRONG></FONT></TD>
<TD class=xl22
style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; BORDER-LEFT: windowtext; WIDTH: 141pt; BORDER-BOTTOM: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent"
width=188><FONT face=Arial size=2><STRONG>Plug in</STRONG></FONT></TD>
<TD class=xl22
style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; BORDER-LEFT: windowtext; WIDTH: 110pt; BORDER-BOTTOM: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent"
width=147><FONT face=Arial size=2><STRONG>Normal</STRONG></FONT></TD></TR>
<TR style="HEIGHT: 42pt; mso-height-source: userset" height=56>
<TD class=xl23
style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 137pt; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 42pt; BACKGROUND-COLOR: transparent"
width=183 height=56><FONT face=Arial size=2><STRONG>real<SPAN
style="mso-spacerun: yes"> </SPAN>0m34.433s<BR>user<SPAN
style="mso-spacerun: yes"> </SPAN>0m0.932s<BR>sys<SPAN
style="mso-spacerun: yes">
</SPAN>0m21.352s</STRONG></FONT></TD>
<TD class=xl23
style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext; WIDTH: 141pt; BORDER-BOTTOM: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent"
width=188><FONT face=Arial size=2><STRONG>real<SPAN
style="mso-spacerun: yes"> </SPAN>0m23.726s<BR>user<SPAN
style="mso-spacerun: yes"> </SPAN>0m0.908s<BR>sys<SPAN
style="mso-spacerun: yes">
</SPAN>0m21.388s</STRONG></FONT></TD>
<TD class=xl23
style="BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext; BORDER-LEFT: windowtext; WIDTH: 110pt; BORDER-BOTTOM: windowtext 0.5pt solid; BACKGROUND-COLOR: transparent"
width=147><STRONG><FONT face=Arial size=2>real<SPAN
style="mso-spacerun: yes"> </SPAN>0m23.329s<BR>user<SPAN
style="mso-spacerun: yes"> </SPAN>0m1.132s<BR>sys<SPAN
style="mso-spacerun: yes">
</SPAN>0m20.968s</FONT></STRONG></TD></TR></TBODY></TABLE></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><SPAN class=771454605-24112009><FONT face=Arial>The results are similiar
with multiple Port Multipliers (Si3726, Si4726 and EXAR PMP) and multiple Host
controllers (Si3132 and sata_fsl).</FONT></SPAN></DIV>
<DIV><SPAN class=771454605-24112009><FONT face=Arial></FONT></SPAN> </DIV>
<DIV><SPAN class=771454605-24112009><FONT face=Arial>As the behaviour with
multiple Host controllers and Port Multipliers is the same so this seems to be
an issue with libata stack.</FONT></SPAN></DIV>
<DIV><SPAN class=771454605-24112009><FONT face=Arial>Is there already a patch
for this issue? Any pointers or help to fix this will be greatly
appreciated.</FONT></SPAN></DIV>
<DIV><SPAN class=771454605-24112009><FONT face=Arial></FONT></SPAN> </DIV>
<DIV></SPAN></SPAN></FONT><FONT face=Arial><FONT size=2>Best Regards<SPAN
class=771454605-24112009>,</SPAN></FONT></FONT></DIV>
<DIV align=left><FONT face=Arial size=2>Anju</FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Applications
Engineer </SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN class=771454605-24112009>Freescale
Semiconductor</SPAN></FONT></DIV></BODY></HTML>