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Intel Developers Demo USB 3.0 Throughput On Linux

Posted by timothy on from the future-sweetness dept.

Sarah Sharp writes "Intel's Open Source Technology Center is working on USB 3.0 support for Linux. USB 3.0 has wire speeds of 5Gbps and promises to be 10 times faster than USB 2.0. A recent video demo shows speeds that are 3.5 times faster than USB 2.0. The USB 3.0 drivers will be submitted to the mainline kernel when the eXtensible host controller interface (xHCI) specification reaches a 1.0 release."

21 of 231 comments (clear)

  1. What's in a name... by alain94040 · · Score: 5, Insightful

    USB 2.0 gave us high-speed and full-speed. Some marketing department had to work really hard on the USB 3.0 specs, to come up with... super-speed.

    Now let's talk about the obvious problem: at 5 Gbit/s, it's faster than the Ethernet in my house (1 Gbit/s). Am I the only one who didn't really notice a 10X speed improvement when moving from 100 Mbit Ethernet to gigabit Ethernet? Conventional hard drives are just too slow.

    Maybe SSD + USB 3.0 would be really cool. Imagine a Flash based HD camera talking to a Flash based hard drive. Is 2009 the year of the Flash?

    Which brings me back to my original point: for the next generation USB, I propose the name flash-speed :-)

    PS: thanks to Intel for helping Linux stay on the leading edge. It looks like Linux may even support this before Windows, thanks to the Windows 7 schedule... I just wish Intel's pre-conditions on contributing to the xHCI specs didn't start with stuff like:

    Step 1. Print and execute the xHCI Contributor agreement. Note: The agreement must be executed by a corporate officer.

    --
    http://fairsoftware.net/

    1. Re:What's in a name... by Microlith · · Score: 4, Insightful

      This is why Intel is pushing USB: it is entirely CPU dependent.

      You won't notice it when you're running with X * 2 logical cores. It'll be shuffled off to some low utilization core.

    2. Re:What's in a name... by John+Allsup · · Score: 5, Interesting

      I guess for hard drives, the question is how close to eSATA it gets.
      Also, does USB3 still have the CPU overhead and latency of earlier USB compared to FW?

      --
      John_Chalisque
    3. Re:What's in a name... by Mad+Merlin · · Score: 4, Informative

      'bursty' ... is that sort of like 'minty'? ;)

      No, it's that max speeds for USB 2.0 refer to the max burst speeds, not the maximum sustainable speed. A single 7200 RPM drive attached via USB 2.0 will be substantially slower than if you attached it via SATA or IDE, even though 60 MB/s (= 480 Mbit/s) should be enough for most drives.

      --
      Game! - Where the stick is mightier than the sword!
    4. Re:What's in a name... by metalhed77 · · Score: 4, Interesting

      That USED to be true. It's not the hard drive, all the layers that get put in between when you access a disk over the network. Modern hard drives can easily do 60MB/s sustained.

      For instance, I have a couple raid6 arrays which clock in at about 250 MB/s and 150MB/s natively. If I hook that machine up directly to another machine's ethernet port I only get about 30MB/s sharing the device w/ iSCSI. SMB and NFS yield similar results. This is true even though I can get over 900Mbps using iperf.

      Sharing disks over gig-e sucks when you actually need throughput. It's great for when you just need to expand a SAN and speed is secondary. I've heard that bonding two Gig-e cards doesn't realize much of an improvement FWIW, so I assume latency is part of the reason it's slower.

      --
      Photos.
    5. Re:What's in a name... by Gazzonyx · · Score: 4, Funny

      USB 2.0 gave us high-speed and full-speed. Some marketing department had to work really hard on the USB 3.0 specs, to come up with... super-speed.

      I'm holding out for WARP speed...

      I'm holding out for plaid speed...

      --

      If I mod you up, it doesn't necessarily mean I agree with what you've said, sorry.

    6. Re:What's in a name... by 0100010001010011 · · Score: 4, Informative

      Again, bull shiat. Use google before stating "recent developments."

      USB 2.0 was released in April 2000.

      Those licensing fees were announced in May 1999.

      In Jan 1999 Apple announced that it would be $1 per port. As far as I know it's always been $1 per port. Now I don't know of any devices with 10 ports on them (Making the licensing fee $10). Here's a CNET article from the same time.

      Both were before USB2.0 was released and considerably less than what you claim.

  2. Wha? by Weaselmancer · · Score: 4, Informative

    Could you please explain that a bit?

    It's my understanding that high throughput drivers usually use DMA.

    In my experience polled mode drivers are pretty rare. Especially in high throughput.

    --
    Weaselmancer
    rediculous.
    1. Re:Wha? by Hal_Porter · · Score: 5, Informative

      Yup the host sets up a structure in memory which lists all the USB endpoints. When a driver wants to do some IO it asks the host controller driver which adds a request into the structure with a pointer to a buffer. The host controller hardware reads the structure with busmaster DMA and generates the USB packets. When the device answers the host controller DMAs the data into the the driver's buffer interrupts the CPU. Then the host controller can pass the buffer back to the driver. Polling is done by leaving the request in the structure, it doesn't require any CPU activity. Intel like USB because they invented it, not as some sort of conspiracy to load your CPU.

      --
      echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
    2. Re:Wha? by lysergic.acid · · Score: 4, Interesting

      so why do FireWire 400 readers still consistently beat out USB 2:

      While USB 2.0's theoretical 480Mbp/s (60MBp/s) throughput should be sufficient for UDMA 4 CompactFlash, realthroughput is significantly less. Top hard drive manufacturers typically cite USB 2.0's best speed at 33MB/s, or abouthalf the speed of UDMA 4 CompactFlash, or 25% of UDMA 6 CompactFlash. There are myriad reasons for USB 2.0's'real world' speeds including: CPU overhead from its master/slave arrangement, NRZI encoding, and inexpensivechipset implementations. The USB 2.0 UDMA reader used in the benchmarks above uses one of the latest USBchipsets from Genesys Logic. While a new generation of that chipset should soon be available, we don't foresee itproviding throughput close to half of that of FireWire.

      heck, those benchmarks show that even using FireWire 400 to read a PIO CompactFlash card still beats USB 2.0 UDMA reading a UDMA-enabled CompactFlash card.

    3. Re:Wha? by raynet · · Score: 5, Informative

      Taken from wikipedia: "Although high-speed USB 2.0 nominally runs at a higher signaling rate (480 Mbit/s) than FireWire 400, typical USB PC-hosts rarely exceed sustained transfers of 280 Mbit/s, with 240 Mbit/s being more typical. This is likely due to USB's reliance on the host-processor to manage low-level USB protocol, whereas FireWire delegates the same tasks to the interface hardware. For example, the FireWire host interface supports memory-mapped devices, which allows high-level protocols to run without loading the host CPU with interrupts and buffer-copy operations."

      --
      - Raynet --> .
    4. Re:Wha? by yoyhed · · Score: 4, Insightful

      Yup the host sets up a structure in memory which lists all the USB endpoints. When a driver wants to do some IO it asks the host controller driver which adds a request into the structure with a pointer to a buffer. The host controller hardware reads the structure with busmaster DMA and generates the USB packets. When the device answers the host controller DMAs the data into the the driver's buffer interrupts the CPU. Then the host controller can pass the buffer back to the driver. Polling is done by leaving the request in the structure, it doesn't require any CPU activity. Intel like USB because they invented it, not as some sort of conspiracy to load your CPU.

      I know it's off-topic, but I thought I'd point out why I love Slashdot by comparing it to Digg. If this story were on Digg, the comments would be something like "I BET THIS BE ON NEXT MACBOOK PRO LOL". Here, we get something like your comment in the first thread. <3 /.

      --
      WHO NEEDS SHIFT WHEN YOU HAVE CAPSLOCK/ DAMN1
    5. Re:Wha? by mabhatter654 · · Score: 4, Informative

      This is why you can't have USB-to-USB devices like you have Firewire-to-Firewire devices. It's why USB is very bad for time-sensitive data like music and video, because you're always waiting for the host controller to do something on the CPU, which might be busy.. have you ever seen DMA to memory ever work properly on consumer grade hardware anyway?

      It's not so much a "scam" as it is designing to the market. Firewire devices have a non-trivial price premium because of the device-to-device controller... but that's why they can do things like daisy-chain or direct connect between computers with no special cables. On the other hand USB allows endpoint devices to be made very cheaply.. they have near-zero intelligence if you want. The USB host can be as "thick" or "thin" as the OEM wants... they can put all the host chip control in software drivers to keep chip cost down. They can also put all the control codes for devices in software... remember "wINKjets" that went obsolete with each new Windows version... they have almost no internal software at all.

    6. Re:Wha? by lysergic.acid · · Score: 4, Interesting

      good point. and to be honest, most people don't need FireWire 800/1600 just to transfer a few documents or spreadsheets--or even photos & mp3s--to their computer. the few seconds saved doesn't justify the added cost of FireWire over USB. nor do they need to use a high-speed data bus for their mouse, keyboard, webcam, printer, scanner, or what have you. so it makes sense that USB is more prevalent than FireWire.

      however, FireWire is still extremely useful (and crucial) to certain professionals who regularly work with large files or have to move around large amounts of data, like hi-res/raw images, lossless audio, hi-def video, etc. that's why FireWire is still pretty standard in high-end music & video production equipment. so the idea that FireWire is dead (or can simply be replaced with USB 2.0/3.0) is just poorly informed.

      even the military still uses FireWire for things like the the F-35's vehicle systems network:

      1394b is playing a pivotal role in the F-35 Lightning II program, providing guaranteed quality of service with predictable latencies in real-time control applications. More than 70 1394 devices are delivering information about mission details, communication systems, weapon systems, engine controls, and flight controls.

      the IEEE-1394B data bus is similarly employed in the F-22 Raptor for which it was developed. and NASA also uses it to monitor debris during launches amongst other mission-critical applications.

  3. Re:cool, at least it is progress by thermian · · Score: 5, Funny

    yeah yeah, i read the comments about gigabit ethernet being faster, thats not the point, usb 3 is still better than usb 2, enjoy the weekend...

    We're geeks, reading stuff like this *is* enjoying the weekend.....

    --
    A learning experience is one of those things that say, 'You know that thing you just did? Don't do that.' - D. Adams
  4. latency badness by r00t · · Score: 4, Interesting

    USB suffers from 1 ms time quantization and thus latency. I see nothing about fixing this.

    Example badness:

    When running MIDI over USB, timing is forced onto 1 ms slots. Normally when playing a chord, the keys don't all hit at exactly the same moment. You can't really tell, except that this makes the music sound natural. With the 1 ms problem, the keys happen at exactly the same moment (bad) or spread out into two separate events (worse).

  5. Compared to USB 1... by MonoSynth · · Score: 5, Interesting

    This shows where Linux is nowadays. It took literally years before USB1 was even supported and now Intel uses Linux to prove USB3's performance!

    1. Re:Compared to USB 1... by MSG · · Score: 4, Informative

      Too bad they used Windows to show it performing about twice as fast as the Linux test ...

      The tests were nothing alike. The Linux demo was sending data to an actual storage device, not to a loopback device designed only to test throughput. The Linux driver also had a great deal of debugging code running which contributed to the relatively low throughput.

      None of which is to say that Linux was or deserved to be the star of this show. It's nice, however, to see technology vendors demonstrating software on platforms other than Windows.

  6. Re:Future Problems..... by Jeoh · · Score: 4, Funny

    USB 7.0 Monster-Speed USB 8.0 Ludicrous-Speed USB 9.0 HOLY SHIT

  7. Comment removed by account_deleted · · Score: 4, Interesting

    Comment removed based on user account deletion

  8. Who needs USB anymore ? by billcopc · · Score: 4, Interesting

    Why are they wasting everyone's time with USB 3.0, when the rest of the universe is shifting toward Ethernet as a common interconnect ? Note I didn't say IP, just Ethernet - good old CAT-5.

    Frig, if the audio folks have already started that transition, then what the hell is Intel doing ? The audio industry is probably the most retarded in the world (according to my failed expectations), and even they see that Ethernet is a cost-effective and braindead simple replacement for all these proprietary cables we've had to contend with over the years.

    --
    -Billco, Fnarg.com