О скоростях передачи данных на шинах между кеш-памятью второго и третьего уровней и между процессором и оперативной памятью в современных компьютерах

In this paper, a modern CPU architecture with several different cache levels is described, and current CPU performance limitations such as silicone physical limitations or frequency increase bounds are mentioned. As usual, changes of the currently existing architecture are proposed as a way of increasing CPU performance, data rates on the internal and external CPU interfaces must be known. It would help to assess applicability of proposed solutions and allow to optimize them. This paper is aimed at getting real values of traffic on L2-L3 cache interface inside CPU and CPU-RAM bus load as well as show dependencies of total traffic on the interfaces of interest on the number of active cores, CPU frequency and test type. Measurements methodology using Intel Performance Counter Monitor by Intel is provided and equations that allow to get data rates from internal CPU counters are explained. Both real life and synthetic tests are described. Dependency of total traffic on the number of active cores and dependency of total traffic on CPU frequency are provided as plots. Dependency of total traffic on test type provided as bar plot for multiple CPU frequencies.В данной работе рассматривается архитектура используемых в настоящее время центральных процессоров и ограничения их производительности в современном виде. Так как чаще всего для повышения производительности центральных процессоров предлагаются решения, связанные с изменением существующей архитектуры, необходимо иметь представление о скоростях передачи данных внутри процессора и на шинах, подходящих к нему. Это позволит оценить применимость предлагаемых решений и даст возможность их оптимизировать. В этой статье решается задача измерения реальных скоростей передачи данных на интерфейсе между кеш-памятью второго и третьего уровней внутри процессора и на интерфейсе между процессором и оперативной памятью, а также изучения зависимости численных результатов от количества активных ядер, тактовой частоты процессора и типа проводимого теста. В статье приводится методология проведения измерений с помощью программного инструмента Intel Performance Counter Monitor от компании Intel, а также приводятся формулы для получения итогового результата из полученных в ходе измерений значений. Приведено подробное описание тестов, имитирующих реальную нагрузку на центральный процессор, и синтетических тестов. Зависимости скоростей передачи данных от количества активных ядер и от тактовой частоты процессора представлены в виде графиков. Зависимости скоростей передачи данных от типа теста представлены в виде столбиковых диаграмм для трех различных значений тактовой частоты процессора

Neutralising antibodies for West Nile virus in horses from Brazilian Pantanal

Despite evidence of West Nile virus (WNV) activity in Colombia, Venezuela and Argentina, this virus has not been reported in most South American countries. In February 2009, we commenced an investigation for WNV in mosquitoes, horses and caimans from the Pantanal, Central-West Brazil. The sera of 168 horses and 30 caimans were initially tested using a flaviviruses-specific epitope-blocking enzyme-linked immunosorbent assay (blocking ELISA) for the detection of flavivirus-reactive antibodies. The seropositive samples were further tested using a plaque-reduction neutralisation test (PRNT90) for WNV and its most closely-related flaviviruses that circulate in Brazil to confirm the detection of specific virus-neutralising antibodies. Of the 93 (55.4%) blocking ELISA-seropositive horse serum samples, five (3%) were seropositive for WNV, nine (5.4%) were seropositive for St. Louis encephalitis virus, 18 (10.7%) were seropositive for Ilheus virus, three (1.8%) were seropositive for Cacipacore virus and none were seropositive for Rocio virus using PRNT90, with a criteria of > four-fold antibody titre difference. All caimans were negative for flaviviruses-specific antibodies using the blocking ELISA. No virus genome was detected from caiman blood or mosquito samples. The present study is the first report of confirmed serological evidence of WNV activity in Brazil

Оценка требуемых скоростей передачи данных при организации беспроводной связи между ядрами центрального процессора

In this paper, a principal architecture of common purpose CPU and its main components are discussed, CPUs evolution is considered and drawbacks that prevent future CPU development are mentioned. Further, solutions proposed so far are addressed and a new CPU architecture is introduced. The proposed architecture is based on wireless cache access that enables a reliable interaction between cores in multicore CPUs using terahertz band, 0.1-10THz. The presented architecture addresses the scalability problem of existing processors and may potentially allow to scale them to tens of cores. As in-depth analysis of the applicability of the suggested architecture requires accurate prediction of traffic in current and next generations of processors, we consider a set of approaches for traffic estimation in modern CPUs discussing their benefits and drawbacks. The authors identify traffic measurements by using existing software tools as the most promising approach for traffic estimation, and they use Intel Performance Counter Monitor for this purpose. Three types of CPU loads are considered including two artificial tests and background system load. For each load type the amount of data transmitted through the L2-L3 interface is reported for various input parameters including the number of active cores and their dependences on the number of cores and operational frequency.Рассматривается современная архитектура процессоров общего назначения, ее основные компоненты, описывается эволюция, а также подчеркиваются проблемы, препятствующие дальнейшему развитию такой архитектуры. Далее рассмотрены предложенные ранее пути развития процессоров, подчеркиваются их недостатки и предлагается новая архитектура, основанная на беспроводном доступе к кеш-памяти в многоядерных процессорах. В основе предлагаемого решения лежит организация надежного обмена данными между кешем третьего уровня и ядрами процессора через беспроводной канал в терагерцовом диапазоне. Таким образом, масштабируемость системы повышается до десятков и, потенциально, сотен ядер. В то же время, детальный анализ применимости предложенного решения требует точного предсказания количества информации, передаваемой между ядрами и кеш-памятью в процессорах текущего и следующего поколения. В данной работе рассматриваются основные подходы к построению оценки количества передаваемых данных, выделены их достоинства и недостатки. Авторы останавливают свой выбор на непосредственных измерениях количества данных с помощью существующих программных инструментов. Для измерений используется программный инструмент Intel Performance Counter Monitor, позволяющей оценить количе- ство данных, передаваемых между кеш-памятью второго и третьего уровней каждого ядра. В работе рассматриваются три варианта нагрузки на ядро – два искусственных теста и фоновая нагрузка от операционной системы. Для каждого типа нагрузки в работе приведены численные значения количества данных, проходящих по шине между кешем второго и третьего уровней, и показана их зависимость от тактовой частоты работы процессора и количества ядер

Influenza A Viruses from Wild Birds in Guatemala Belong to the North American Lineage

The role wild bird species play in the transmission and ecology of avian influenza virus (AIV) is well established; however, there are significant gaps in our understanding of the worldwide distribution of these viruses, specifically about the prevalence and/or significance of AIV in Central and South America. As part of an assessment of the ecology of AIV in Guatemala, we conducted active surveillance in wild birds on the Pacific and Atlantic coasts. Cloacal and tracheal swab samples taken from resident and migratory wild birds were collected from February 2007 to January 2010.1913 samples were collected and virus was detected by real time RT-PCR (rRT-PCR) in 28 swab samples from ducks (Anas discors). Virus isolation was attempted for these positive samples, and 15 isolates were obtained from the migratory duck species Blue-winged teal. The subtypes identified included H7N9, H11N2, H3N8, H5N3, H8N4, and H5N4. Phylogenetic analysis of the viral sequences revealed that AIV isolates are highly similar to viruses from the North American lineage suggesting that bird migration dictates the ecology of these viruses in the Guatemalan bird population

Searches for the Zγ decay mode of the Higgs boson and for new high-mass resonances in pp collisions at √s=13 TeV with the ATLAS detector

This article presents searches for the Zγ decay of the Higgs boson and for narrow high-mass resonances decaying to Zγ, exploiting Z boson decays to pairs of electrons or muons. The data analysis uses 36.1 fb−1 of pp collisions at √s=13 recorded by the ATLAS detector at the CERN Large Hadron Collider. The data are found to be consistent with the expected Standard Model background. The observed (expected — assuming Standard Model pp → H → Zγ production and decay) upper limit on the production cross section times the branching ratio for pp → H → Zγ is 6.6. (5.2) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125.09 GeV. In addition, upper limits are set on the production cross section times the branching ratio as a function of the mass of a narrow resonance between 250 GeV and 2.4 TeV, assuming spin-0 resonances produced via gluon-gluon fusion, and spin-2 resonances produced via gluon-gluon or quark-antiquark initial states. For high-mass spin-0 resonances, the observed (expected) limits vary between 88 fb (61 fb) and 2.8 fb (2.7 fb) for the mass range from 250 GeV to 2.4 TeV at the 95% confidence level

Measurement of the Higgs boson coupling properties in the H → ZZ* → 4 decay channel at √s = 13 TeV with the ATLAS detector

The coupling properties of the Higgs boson are studied in the four-lepton (e, μ) decay channel using 36.1 fb−1 of pp collision data from the LHC at a centre-of-mass energy of 13 TeV collected by the ATLAS detector. Cross sections are measured for the main production modes in several exclusive regions of the Higgs boson production phase space and are interpreted in terms of coupling modifiers. The inclusive cross section times branching ratio for H → ZZ∗ decay and for a Higgs boson absolute rapidity below 2.5 is measured to be 1. 73 − 0.23 + 0.24 (stat.) − 0.08 + 0.10 (exp.) ± 0.04(th.) pb compared to the Standard Model prediction of 1.34±0.09 pb. In addition, the tensor structure of the Higgs boson couplings is studied using an effective Lagrangian approach for the description of interactions beyond the Standard Model. Constraints are placed on the non-Standard-Model CP-even and CP-odd couplings to Z bosons and on the CP-odd coupling to gluons

Measurement of τ polarisation in Z/γ∗ → ττ decays in proton–proton collisions at √s = 8 TeV with the ATLAS detector

This paper presents a measurement of the polarisation of τ leptons produced in Z/γ ∗ → ττ decays which is performed with a dataset of proton—proton collisions at √s = 8 TeV, corresponding to an integrated luminosity of 20.2 fb−1 recorded with the ATLAS detector at the LHC in 2012. The Z/γ∗ → ττ decays are reconstructed from a hadronically decaying τ lepton with a single charged particle in the final state, accompanied by a τ lepton that decays leptonically. The τ polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic τ decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The τ polarisation extracted over the full phase space within the Z/γ∗ mass range of 66 < mZ/γ∗ < 116GeV is found to be Pτ = −0.14±0.02(stat)±0.04(syst). It is in agreement with the Standard Model prediction of Pτ = −0.1517 ± 0.0019, which is obtained from the ALPGEN event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA τ decay library

Search for supersymmetry in events with b-tagged jets and missing transverse momentum in pp collisions at √s = 13 TeV with the ATLAS detector

A search for the supersymmetric partners of the Standard Model bottom and top quarks is presented. The search uses 36.1 fb−1 of pp collision data at √s = 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Direct production of pairs of bottom and top squarks (b˜1 and t˜1) is searched for in final states with b-tagged jets and missing transverse momentum. Distinctive selections are defined with either no charged leptons (electrons or muons) in the final state, or one charged lepton. The zero-lepton selection targets models in which the b˜1 is the lightest squark and decays via b˜1 → bχ˜01 , where ˜χ01 is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, b˜1 → bχ˜01 and b˜1 → tχ˜±1, or t˜1 → tχ˜01 and t˜1→ bχ˜±1, where ˜χ±1 is the lightest chargino and the mass difference mχ˜±1 − mχ˜01 is set to 1 GeV. No excess above the expected Standard Model background is observed. Exclusion limits at 95% confidence level on the mass of third-generation squarks are derived in various supersymmetry-inspired simplified models

Search for diboson resonances with boson-tagged jets in pp collisions at √s=13 TeV with the ATLAS detector

Narrow resonances decaying into WW, WZ or ZZ boson pairs are searched for in 36.7 fb−1 of proton–proton collision data at a centre-of-mass energy of √s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The diboson system is reconstructed using pairs of large-radius jets with high transverse momentum and tagged as compatible with the hadronic decay of high-momentum W or Z bosons, using jet mass and substructure properties. The search is sensitive to diboson resonances with masses in the range 1.2–5.0 TeV. No significant excess is observed in any signal region. Exclusion limits are set at the 95% confidence level on the production cross section times branching ratio to dibosons for a range of theories beyond the Standard Model. Model-dependent lower limits on the mass of new gauge bosons are set, with the highest limit set at 3.5 TeV in the context of mass-degenerate resonances that couple predominantly to bosons