<html><head><base href="x-msg://967/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Perhaps someone else here has a thought, but it does not make sense to me that loading SDP (which accelerates TCP traffic by by-passing the TCP stack) makes lnet faster if you are using <ip>@o2ib, and _not_ <ip>@tcp0 for your NIDs.</div><div><br></div><div>Any chance you've configured both TCP and O2IB nids on the machine, and it is somehow picking the TCP nids to use?</div><div><br></div><div>Can you confirm the "lctl list_nids" output, and your lustre/lnet sections of your modprobe.conf?</div><div><br></div><div>Kevin</div><div><br></div><br><div><div>On Feb 15, 2012, at 12:30 PM, Barberi, Carl E wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div lang="EN-US" link="blue" vlink="purple"><div class="WordSection1" style="page: WordSection1; "><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">We are having issues with LNET performance over Infiniband. We have a configuration with a single MDT and six (6) OSTs. The Lustre client I am using to test is configured to use 6 stripes (lfs setstripe -c 6 /mnt/lustre). When I perform a test using the following command:<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "> dd if=/dev/zero of=/mnt/lustre/test.dat bs=1M count=2000<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">I typically get a write rate of about 815 MB/s, and we never exceed 848 MB/s. When I run obdfilter-survey, we easily get about 3-4GB/s write speed, but when I run a series of lnet-selftests, the read and write rates range from 850MB/s – 875MB/s max. I have performed the following optimizations to increase the data rate:<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">On the Client:<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">lctl set_param osc.*.checksums=0<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">lctl set_param osc.*.max_dirty_mb=256<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">On the OSTs<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">lctl set_param obdfilter.*.writethrough_cache_enable=0<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">lctl set_param obdfilter.*.read_cache_enable=0<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">echo 4096 > /sys/block/<devices>/queue/nr_requests<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">I have also loaded the ib_sdp module, which also brought an increase in speed. However, we need to be able to record at no less than 1GB/s, which we cannot achieve right now. Any thoughts on how I can optimize LNET, which clearly seems to be the bottleneck?<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Thank you for any help you can provide,<o:p></o:p></div><div style="margin-top: 0in; margin-right: 0in; margin-left: 0in; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Carl Barberi<o:p></o:p></div></div><span><ATT00001..txt></span></div></span></blockquote></div><br><br><br>
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