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Tuesday, December 30, 2008

httperf status - 2008-12-30

I have to acknowledge that I have been dropping the ball in regards to completing the next release of httperf. While there has been a good amount of work done on this tool since the last release (0.9.0) I just haven't gotten around to wrapping it up yet.

Anways, I had better get to it now.

Check CVS for the todo list.

Other than simple procrastination, one major reason I put off development was that autoconf support for detecting the c99 constructs I was using wasn't integrated until 2.62.

Then I was going off on tangents, trying to implement my own libevent based http client library (which is definitely a useful project in my own opinion) and working to get mtp support introduced into the kernel.

Anyways, where we stand today is that the head of cvs is not terribly stable at very very high request rates. Maybe this is because httperf has never been able to achieve the rates that we are now reaching before and it has exposed some hithertofore unkown issue.

Whatever, I'll track it down.

As for the libevent migration. Well, Adrian Chadd was kind enough to do a partial port. However there is much more work to be done in this area such as migrating timers, timeouts, dns and http control into the libevent core loop.

Long term, httperf will dramatatically shrink in size. Event logic, the http client, and metrics collection can all be loaded onto libevent and some (as of yet unwritten) plugins. httperf will be a set tools implementing various workload generators and may further evolve into a workload language implementation.

Monday, December 29, 2008

A spin with gnome-blog

I was poking around the software repository for opensuse 11.1, and came across a tool called gnome-blog. This is a panel applet which is supposed to allow me to post to my blog directly from the desktop rather than the supposedly tedious process of opening the blog website and posting from there.

Anyways, the tool is supposed to allow me to drag and drop images inline with the text, so I figure I will give it a whirl.

This version of gnome-blog is from 2006, and appears to be the most recent, so I suppose that development has stalled. Google has failed to deliver anything of interest more recent than that.

Update: I am not impressed. So long gnome-blog.


Friday, December 26, 2008

Linux Kernel Space Media Transfer Protocol

So after a couple years of pondering I have finally begun work on implementing a kernel space driver for the media transfer protocol.

Yes, yes, this is my first foray since university into kernel space, but I have had enough of the user-space solutions to implementing the media transfer protocol. Hundreds of devices have now implemented the darn thing (including my iriver clix if you recall), and what's more the folks have finally published the 1.0 version of the standard.

First here is a bit of the technical reasoning.

  1. Already two distinct user-space implementations which both share similar drawbacks. libmtp, and libgphoto

  2. Dependant on libusb which has stalled in development

  3. Race condition in device connection, first application to detect and connect blocks any other software from using the device until connection is dropped

Etc, the current implementation suffers from all the problems that user space drivers suffer from in the monolithic world (even the microsoft implementation has this going on). Also, it's about time I get my hands dirty in the kernel for pete's sake.

So how is this thing going to work you might ask?

Well, here is how I see it right now, and others are welcome to chime in on this.

The protocol is implemented partly in kernel space, and partly in user-space depending on necessity and appropriateness.

Kernel Space Driver (mtp):
Connects and manages all operations:
Exposes file hierarchies as a mountable file system
Implements protocol for transferring straight files.
Issues device handles to userspace which can be used asynchronously (no more device pointers!)
Automatic device connection

User Space Library (libmtp-media)
Implements protocol for managing media (including meta-data) (music, pictures, video, etc)

User Space Library (libmtp-cal)
Implements protocol for managing contact and calendar (vcard, ical, etc)

Essentially the protocol implementation will be separated across a variety of locations.

Anywho, after an hour or so of fiddling, here is the latest line from dmesg:

usb 4-5: new high speed USB device using ehci_hcd and address 9
usb 4-5: configuration #1 chosen from 1 choice
mtp: USB Skeleton device now attached to USBSkel-192
usb 4-5: New USB device found, idVendor=4102, idProduct=112a
usb 4-5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 4-5: Product: iriver clix
usb 4-5: Manufacturer: iriver Limited
usb 4-5: SerialNumber: 41dff81c000000f33230303530313031
usb 4-5: USB disconnect, address 9
mtp: USB Skeleton #192 now disconnected

Not much, but hey it's the beginning of the road here.

Lastly, if anyone wants to employ me to design this, I am certainly on the market.

-Ted Bullock