Muli Ben-Yehuda's journal

October 23, 2005

weekend shenanigans

Filed under: Uncategorized — Muli Ben-Yehuda @ 11:52 AM

On Friday I switched our home connection from ADSL to cable, since we’re getting cable practically for free from work and ADSL is decidedly non-free. I’ve been resisting this change for a while, since I have somewhat of an emotional attachment to ADSL, but Orna has been pushing for it and I gave up. Cable works quite well so far.

Then I continued working on the DMA mapping patch and after testing it on a bunch of machines sent the first version (-C1) to lkml.

In the evening we caught Kate and Leopold on TV, which was surprisingly enjoyable.

On Saturday, I woke up early and submitted a follow up Xen patch to this bug. The Cambridge guys committed both my and Jeremy Katz’s patches, so the follow-up reverted mine (Jeremy’s was much prettier). Then we drove to Tel Aviv for lunch at Orna’s sister’s and her boyfriend’s apartment. Lunch was highly enjoyable and their apartment is gorgeous.

In the afternoon we visited omerm and shapirac, and had a horribly geeky discussion. Much fun was had. shapirac mentioned that my PNS posts used to motivate her to work out, so mayhap I’ll resuscitate them. $DEITY knows I need the exercise.

When we got home Orna cooked an amazing dinner, and then I watched “quality TV”, aka The Wire. While watching (perhaps during the detective wake?) I realized that there was a way to eradicate one of the warts of the dma-mapping-ops patch.

The way I structured dma_xxx() is that they call a dma_mapping function if one exists, and otherwise call the default gart_xxx() function. This was done in order to keep the fast path fast (avoid a function pointer call). Unfortunately, for the nommu case, where no gart exists, this requires us to link in gart_xxx(), even though it’s never called. The solution is obvious, even if it did take me a week or so to come up with it – provide empty definitions of gart_xxx() if CONFIG_GART_IOMMU is not defined. While implementing it, I also discovered a couple of buglets – nommu_map_sg() and nommu_unmap_sg() were not getting called, and I erroneously removed a couple of EXPORT_SYMBOLS(). Fixed, tested, and released swiotlb-dma-mapping-ops-D1.

And that’s about it. How was your weekend, gentle reader?


  1. My weekend was uneventful except for eating in the Sukka.
    I’m glad to see you enjoyed yours!

    Comment by moshez — October 23, 2005 @ 11:09 AM | Reply

  2. The PNS posts were inspiring indeed
    I need exercise too! Maybe I will manage to PNS myself….

    Comment by omerm — October 23, 2005 @ 11:57 AM | Reply

    • Re: The PNS posts were inspiring indeed
      Please do, the more the merrier!

      Comment by mulix — October 23, 2005 @ 7:23 PM | Reply

  3. Speaking of workouts – I wrote a small script that scans your journal looking for keywords like ‘gym’, ‘execise’ and ‘workout’.
    The last entry to mention exercise was on Oct. 31 2004 (a year ago!) and it wasn’t particularly motivating. It ends in the immortal words “I’ll exercise more tomorrow”
    I didn’t even realise you stopped posting them such a long time ago.

    Comment by shapirac — October 23, 2005 @ 12:58 PM | Reply

    • Latest I can find is ‘work out’ in June 2005. Which is not to say it doesn’t suck.

      Comment by mulix — October 23, 2005 @ 7:23 PM | Reply

  4. Pushing for it, Yes?
    We have been paying for the cables internet for 8 monthes now, but we did not use it.
    On Thursday, the phone line had a short-circuit. We were left without a voice phone and with a half-working internet. This was a point where the paid-for cable internet did not do any good, because it was never connected. Without internet, we could not figure out easily how to connect using cables.
    Two good things came out of it:
    We do not pay 100 shekels a month to Bezek anymore.
    The Bezek technician switched the lines, so now the line with the many connection points around the house is connected, instead of the one in the study only.

    Comment by Anonymous — October 23, 2005 @ 1:03 PM | Reply

  5. My Weekend
    I’m glad to hear you had a nice weekend. I spent my weekend working on “The
    Case for File Swapping”
    . I had the summary ready much beforehand, and during the weekend, I was able to prepare the
    full text and DocBook/XML markup. I feel that I was very productive.

    Comment by shlomif — October 23, 2005 @ 3:34 PM | Reply

  6. On Friday I switched our home connection from ADSL to cable
    (Disclaimer: the author of this comment works as a tech support rep for Bezeq’s ADSL service. However, the below stuff is written mainly from my experience with cables back when I worked for an ISP’s tech support. I have no direct benefit from promoting ADSL and telling the bad stuff about cables which I’m about to tell. However, this is not and should not be considered an objective opinion)
    This said here’s my opinion: The service provided by cable companies in Israel is crappy by unbelievable levels, both technically speaking and, well their customer service sucks (concerning the latter: I haven’t yet seen a company in israel whose customer service doesn’t suck, but theirs does it by levels unheard of even at Bezeq in the “best of times” and at Bezeq this has been improving greatly with the privatization). Idiotic customer service notwithstanding, from a purely technological point of view, the cable companies in israel suck. They only recently switched from DOCSIS 1.0 to DOCSIS 1.1 (and not in all areas!), whereas cable companies abroad have been working with DOCSIS 2.0 for quite a long time and DOCSIS 3.0 specification is, as far as I know, due out soon. In practise this means that authentication is done via mac address of the modem and is prone to very simple mac spoofing. Also, many people experience frequengt disconnections from the internet because the ip address of the modem is sometimes changed at random, which the cable companies refuse to acknowledge.
    True, some people have been reporting the internet over cables to work very well, but this isn’t consistent even with people living in the same house, not to mention even a neighbourhood. Over 75% of people switching from ADSL to cables later switch back despite the higher price. Tells something, I think.

    Comment by talash — October 23, 2005 @ 4:52 PM | Reply

    • I appreciate the feedback. The reason for switching was purely financial, not technical – it’s hard to justify paying Bezeq + ISP for ADSL when you get Cable + ISP for free. If the service indeed turns out to be quite as bad as you describe, I have no doubt we’ll switch back. We’re a household of net junkies ๐Ÿ™‚ But – it will have to be bad indeed, because we’ve had many “interesting” experiences with ADSL, so a simple disconnection now and then won’t phase us much.

      Comment by mulix — October 23, 2005 @ 7:27 PM | Reply

  7. For the record, for a long time now Bezeq uses both PPPOE and PPPOA and in fact every ethernet modem shipped by Bezeq after the old Alcatel uses PPPOE, which is no problem to configure under linux. Don’t you think you should update your page and note that fact?

    Comment by talash — October 23, 2005 @ 4:57 PM | Reply

    • I should… and eventually will. If you feel like it, send a patch and I’ll apply it, with full attribution of course. You can consider it a poor-man’s wiki ๐Ÿ™‚

      Comment by mulix — October 23, 2005 @ 7:28 PM | Reply

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