<br><br><p><DEFANGED_div><DEFANGED_span class="gmail_quote">On 11/5/07, <b class="gmail_sendername">Bob Kline</b> <<a href="mailto:bob.kline@gmail.com">bob.kline@gmail.com</a>> wrote:</DEFANGED_span><blockquote class="gmail_quote" DEFANGED_style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br><br><p><DEFANGED_span class="q">On Oct 22, 2007 11:05 AM, Justin Denick <<a href="mailto:justin.denick@gmail.com" target="_blank" DEFANGED_onclick="return top.js.OpenExtLink(window,event,this)">justin.denick@gmail.com</a>> wrote:
<br><blockquote class="gmail_quote">
<br> <p><br>Be sure to see what the DMA specs are too.<br><br>hdparm -cuda /devx<br><br>As you can see it makes a big differnece<br><br></p>justin@da-boxx ~ $ sudo hdparm -t /dev/hda<br><br>/dev/hda:
<br> Timing buffered disk reads: 166 MB in 3.02 seconds = 54.92 MB/sec<br>justin@da-boxx ~ $ sudo hdparm -d0 /dev/hda<br><br>/dev/hda:<br> setting using_dma to 0 (off)<br> using_dma = 0 (off)<br>justin@da-boxx ~ $ sudo hdparm -t /dev/hda
<br><br>/dev/hda:<br> Timing buffered disk reads: 18 MB in 3.26 seconds = 5.53 MB/sec<br>justin@da-boxx ~ $ sudo hdparm -d1 /dev/hda<br><br>/dev/hda:<br> setting using_dma to 1 (on)<br> using_dma = 1 (on)<br>justin@da-boxx
~ $ sudo hdparm -t /dev/hda<br><br>/dev/hda:<br> Timing buffered disk reads: 166 MB in 3.02 seconds = 54.88 MB/sec<br>justin@da-boxx ~ $<br><br>It's a kernel option<br>CONFIG_IDEDMA_AUTO=y<p><br>
</p></blockquote></DEFANGED_span></p><p><br>hdparm -cuda /dev/x</p></blockquote><p><DEFANGED_div><br>I forgot about one thing Bob.<br>hdparm only works for IDE drives, since your drive is interfaced via USB it must be /dev/s-something right?
<br><br>if that it the case than DMA shouldn't be needed at all.<br><br>As the purpose of DMA is to free up the processor maybe you should watch the Load Avg when copying a file to see if it's<br>abnormally high.<br>
<br></p><DEFANGED_div><br><blockquote class="gmail_quote" DEFANGED_style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><p>only reports for a: "readahead = 256 (on) <br><br>Running "hdparm -d1 /dev/x"
<br>result in "HDIO_SET_DEM failed: Invalid argument."<br><br>
The hdparm man page suggest that<br>in rare cases one has to use the -X<br>parameter. It also says this can cause<br>real headaches.<br><br> -Bob<br><br></p><p></p><br>
<br>_______________________________________________<br>grlug mailing list<br><a DEFANGED_onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:grlug@grlug.org">grlug@grlug.org</a><br><a DEFANGED_onclick="return top.js.OpenExtLink(window,event,this)" href="http://shinobu.grlug.org/cgi-bin/mailman/listinfo/grlug" target="_blank">
http://shinobu.grlug.org/cgi-bin/mailman/listinfo/grlug</a><br></blockquote></p><DEFANGED_div><br><br clear="all"><br>-- <br>In vino veritas.<br> [In wine there is truth.]<br> -- Pliny