RpmFind
fr2.rpmfind.net has been quite overloaded since the last three weeks, when Fedora Core 5 has been released. This mirror must be particularily popular, because the traffic remains high, when other mirrors witnessed the usual decrease after a few days only.

The Fedora archive is on a single physical disk, and the machine has difficulties to handle those approx. 300 simultaneous ftp clients accessing the same disk concurrently. The maximum 4GB available RAM for this 32 bits architecture is clearly not enough to provide a good caching effect.

An interesting tuning that I noticed during this period is the importance of the choice of the IO scheduler related to this disk. The default CFQ is quite inefficient in this kind of situation, mainly characterized by random accesses. More details follow. This is a bad news, because I wish I could use the ionice feature of this scheduler to prioritarize some processes, like the one syncing from the master ftp sites, versus the regular ftpd processes. The ionice commandline shows good improvements to resolve this situation. ftpd processes are put the the third IO class, idle class, meaning that they are served only when no other processes require access. Regular processes are by default in the second class, best effort, and have consequently a higher priority. The result is encouraging : the +300 ftpd processes in the idle class accessing the same filesystem don't slow the interactive ones accessing the same area.

Unfortunately, this scheduler is not useable in my setup for two reasons : first, the global disk throughput is considerably lower with CFQ that with the AS scheduler (9k sectors/s for CFQ vs 14k for AS). And secondly, after a few minutes of use, the block layer thread, kblockd, begins to take all the available CPU time, presumably spending most of its time in locks contention, as showed in this oprofile report :

samples  %        symbol name
102088   19.4653  cfq_dispatch_requests
87969    16.7732  _raw_spin_unlock
77994    14.8712  _raw_spin_lock
31229     5.9545  _spin_unlock_irqrestore

Fedora Core 5
Fedora Core 5 is a nicely polished distro. I appreciate the efforts made to provide a better desktop experience, especially on the laptop. The NetworkManager infrastructure and the power management improvements are the major hits of this new release. Having a machine that can easily suspend to ram or suspend to disk, and switches its network interfaces between wired and wireless on the fly is a real comfort for the laptop user. Compared to the customization nightmare that was needed to achieve the same result on FC4, this is day vs night.

I see a downside of this friendly user behavior in the support of the latest graphic cards. 3D on the desktop is now practically a reality, with the AIGLX and XGLX projects. But supporting this feature will require proprietary drivers. This is already the case with NVIDIA, and it seems that ATI will follow the same path with their new chipsets. This is worrying.

Fedora Core 5 addons
I put on fr2.rpmfind.net some packages that I rebuild for each current Fedora release, for use on my own box. This is a kind of personal -extra repository. If you're interested and want to follow these updates, there's a bellet-release package that installs the yum .repo file, and the related GPG signing key. This repository has dependancies with fedora-extras, so you should also enable this one.

Among goodies, there's some tools that interface with the iRiver MP3 player, a CVS snapshot of the FlightGear flight simulator, the venerable and old XV image viewer, the rhn-applet, the VTK aka Visualization Toolkit.

Life
Since the last three months, a new building is being constructed on the other side of my street. It should have something like three level of underground car park, so the ground has been digged quite deeply. As a side effect, a part of the street now begins to sink in some places close to this excavation, and disturning small crackling appear on the pavement on the same side than my own building. The street is currently closed to cars circulation, and civil engeenerings are currently trying to consolidate the situation...