Palestras na USP - Tecnologia de ponta em sistemas livres - duas palestras com convidados internacionais

Por Nelson Y

Data de Publicação: 27 de Agosto de 2010

Fonte: IME/USP

O CCSL tem o prazer de convidar todos a assistir duas palestras internacionais de alto nível, ministradas por palestrantes fortemente envolvidos com seus respectivos temas. Christoph Hellwig, um dos desenvolvedores do Linux envolvido primariamente com sistemas de arquivos, vai falar sobre o novo mecanismo de caches de disco no kernel do linux, que deve aumentar a confiabilidade do sistema e, ao mesmo tempo, garantir um melhor desempenho; e Ian Pratt, líder da comunidade Xen.org, vai falar sobre essa comunidade, o projeto Xen, seus planos para o futuro etc.

As palestras serão ministradas em inglês e ocorrem nesta segunda-feira, dia 30, das 14:00h às 16:00h (Christoph Hellwig) e das 16:00h às 18:00h (Ian Pratt), no auditório Antonio Gillioli, bloco A do IME/USP. Abaixo, os resumos das palestras e currículos dos palestrantes.

Título: A future without barriers - disk cache control and I/O ordering in Linux
Data: Segunda-feira, 30/08/2010, às 14:00h
Local: Auditório Antonio Gillioli, bloco A, IME/USP
Palestrante: Christoph Hellwig

Resumo: This presentation tells a tale of caches, ordering, lies and misconceptions. It all started when the disk started lying to us. When consumer disks started to implement volatile caches with write back semantics hell broke lose for existing filesystem implementation. Before that point they could rely on internal I/O ordering for providing data integrity, but now that disks signaled I/O completion before data actually was on stable storage this strategy fell flat.

Initially Linux like most other operating systems ignored this issue and let users chose between going really fast and actually having reliably storage, with default setting of cheap disks being lose, but fast. The concept of I/O barriers was introduced to solve that dilemma. The I/O barrier semantics implemented in Linux in 2002 mixed the cache control aspect with data ordering semantics inspired by the SCSI ordered tag commands, assuming that we can use these to offload ordering to hardware. But in the eight years since no one managed to actually come up with an optimized implementation of this interface, leading to dramatic performance degradation over not using a cache at all for many workloads.

This year we finally designed scheme to replace barriers with a simpler cache control concept that overcomes this limitation, and this presentation explains how we overcame the limitations of the previous scheme.

Sobre o palestrante: Christoph Hellwig has been working with and on Linux for the last ten years, dealing with kernel-related issues much of the time. In addition he is or was involved with various other Open Source projects.

After a number of smaller network administration and programming contracts he worked for Caldera's German development subsidiary on various kernel and userlevel aspects of the OpenLinux distribution.

Since 2004 he has been running his own business focusing on consulting, training and contracting work in the OpenSource hemisphere. Specializing on Linux filesystems and storage he is also active in bordering areas such as virtualization and networking. He has worked for well known customers such as Dell, SGI, IBM, Red Hat and startups like LeftHand Networks and Smapper Applied Data.

Título: Xen.org com Ian Pratt
Data: Segunda-feira, 30/08/2010, às 16:00h
Local: Auditório Antonio Gillioli, bloco A, IME/USP
Palestrante: Ian Pratt

Resumo: Xen.org é a casa do hypervisor de código aberto Xen, rápido, com a base de código padronizada e segura para virtualização de sistemas operacionais. Fundada e liderada por Ian Pratt, a comunidade se beneficia de contribuições de engenheiros senior de mais de 50 fabricantes de hardware, software e segurança. O Xen.org é mantido para o benefício da comunidade pelo conselho consultivo do projeto Xen, que é selecionado a partir dos principais contribuintes do projeto.

A comunidade Xen.org segue estas missões:

• Construir o hypervisor de código aberto padrão da indústria
• Ser a base para produtos de diversos fabricantes
• Manter o Xen como líder de performance
• Ser o primeiro a explorar os novos atributos de virtualização em hardware
• Auxiliar os fornecedores de SO a paravirtualizar seus SOs
• Manter a reputação do Xen em estabilidade de qualidade
• Suportar múltiplos tipos de CPU para grandes e pequenos sistemas
• Estimular a inovação
• Garantir a interoperabilidade de drivers

Sobre o palestrante: Ian Pratt is the chief architect of the Xen project, and chairman of xen.org. He has played a key role in both the architecture of Xen and formation of industry partnerships that led to the emergence of Xen as the leading open source virtualization technology. Ian was a member of faculty at the University of Cambridge Computer Laboratory, where he led the Systems Research Group for over 7 years. He was a founder of XenSource, and is now VP for Advanced Products at Citrix.