A (In)Cast of Thousands: Scaling Datacenter TCP to Kiloservers and Gigabits (CMU-PDL-09-101)

This paper presents a practical solution to the problem of high-fan-in, high-bandwidth synchronized TCP workloads in datacenter Ethernets—the Incast problem. In these networks, receivers often experience a drastic reduction in throughput when simultaneously requesting data from many servers using TCP. Inbound data overfills small switch buffers, leading to TCP timeouts lasting hundreds of milliseconds. For many datacenter workloads that have a synchronization requirement (e.g., filesystem reads and parallel dataintensive queries), incast can reduce throughput by up to 90%. Our solution for incast uses high-resolution timers in TCP to allow for microsecond-granularity timeouts. We show that this technique is effective in avoiding incast using simulation and real-world experiments. Last, we show that eliminating the minimum retransmission timeout bound is safe for all environments, including the wide-area

Sampling locations and phylogenetic network showing genealogical relationships in the CR between reindeer populations.

<p>Map of Northern Eurasia, with focus on the Eurasian Arctic archipelagos, showing the geographic origin of the samples (a) and a MJ network of the 122 CR sequences (400 bp) (b). Five previously described haplotype clusters (<b>Ic</b>, <b>Id</b>, <b>Ie</b>, and <b>II</b>) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0165237#pone.0165237.ref026" target="_blank">26</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0165237#pone.0165237.ref069" target="_blank">69</a>] are identified. The MJ network show haplotype sharing between Svalbard (turquoise), Novaia Zemlia (green) and Pechora River (pink) within sub-cluster <b>Ic</b>. Including the Franz Josef Land samples (asterisk) show that 13 of the 15 ancient samples sequenced were identical to the most common haplotype found on Svalbard and on Novaia Zemlia. We also found one individual with a haplotype belonging to sub-cluster <b>Ie</b>, and one haplotype that is unique for Franz Josef Land. The map (a) is printed here for the first time under a CC BY license, with permission of the cartographer Allessandro Pasquini.</p

Frequencies of CR haplotype clusters in the sampled reindeer populations.

<p>Frequencies of haplotypes belonging to sub-cluster <b>Ic</b>, <b>Id</b>, <b>Ie</b> and cluster <b>II</b> in all seven populations. Haplotypes that did not cluster with any of the previously described clusters were placed in cluster <b>I</b>. Haplotype frequencies are calculated from the 400 bp long fragment for all populations, except haplotype frequencies in the ancient material from Franz Josef Land, which were calculated from the 190 bp long fragment. Haplotype frequencies show that <b>Ic</b> haplotypes are common on Svalbard, Novaia Zemlia and in the ancient material from Franz Josef Land. <b>Ic</b> haplotypes are also found in the Pechora- and Peza River populations, but are absent in the domestic reindeer population sampled on Kolguev.</p

Archaeological site loss in the southeastern United States due to sea level rise within 200 km of the coast.

<p>Data: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref072" target="_blank">72</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref073" target="_blank">73</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref151" target="_blank">151</a>].</p

Land area loss in the southeastern United States due to sea level rise, in sq km.

<p>Data: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref108" target="_blank">108</a>].</p

Population displacement in the southeastern United States due to sea level rise.

<p>Data: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref106" target="_blank">106</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref107" target="_blank">107</a>].</p

Land area in the southeastern United States within 50 m AMSL.

<p>Data: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref108" target="_blank">108</a>].</p

Archaeological site and component loss in South Carolina due to sea level rise within 200 km of the coast.

<p><b>Data: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref073" target="_blank">73</a>].</b> PI = Paleoindian. EA = Early Archaic, MA = Middle Archaic, LA = Late Archaic, AA = Any Archaic, EW = Early Woodland, MW = Middle Woodland, LW = Late Woodland, AW = Any Woodland, M = Mississippian, LP = Late Prehistoric, UP = Unknown Prehistoric, CEP = Contact Era/Protohistoric, 16^th = 16^th Century Historic, 17^th = 17^th Century Historic, 18^th = 18^th Century Historic, 19^th = 19^th Century Historic, 20^th = 20^th Century Historic, UH = Unidentified Historic.</p

DINAA partnerships as of July 2017 with dot density plot showing distribution of cultural resources at low resolution within states whose data have been received thus far.

<p><b>Data: [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188142#pone.0188142.ref073" target="_blank">73</a>].</b> Ohio and most Pennsylvania site data is at county-level resolution.</p

DINAA links information in a wide range of online data repositories, using archaeological site numbers as the common referent.

<p>DINAA directs users to these outlets, but access and content control remains on their systems (black arrows indicate existing linkages, white arrows indicate linkages under development).</p