Return-path: Received: from daemonizer.de ([87.230.16.230]:52392 "EHLO daemonizer.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754824AbXE0Vqj (ORCPT ); Sun, 27 May 2007 17:46:39 -0400 From: Maximilian Engelhardt To: Michael Buesch Subject: Re: b44: regression in 2.6.22 (resend) Date: Sun, 27 May 2007 23:46:16 +0200 Cc: "linux-kernel" , "linux-wireless" , Stephen Hemminger , Arnaldo Carvalho de Melo , Jeff Garzik , Gary Zambrano , netdev@vger.kernel.org, Andrew Morton References: <20070525172431.60affaca@freepuppy> <200705272236.42628.maxi@daemonizer.de> <200705272246.16960.mb@bu3sch.de> In-Reply-To: <200705272246.16960.mb@bu3sch.de> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart13571105.gMBMrhRZdQ"; protocol="application/pgp-signature"; micalg=pgp-sha1 Message-Id: <200705272346.19760.maxi@daemonizer.de> Sender: linux-wireless-owner@vger.kernel.org List-ID: --nextPart13571105.gMBMrhRZdQ Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Sunday 27 May 2007, Michael Buesch wrote: > On Sunday 27 May 2007 22:36:39 Maximilian Engelhardt wrote: > > When I ran 2.6.21.1 or 2.6.22-rc3 without any debugging tools just in > > normal use I didn't notice any problems. It did work fine as I would > > expect it. I think the wget and ping tests here are as they should be. > > > > With 2.6.22-rc2-mm1 I noticed that connections seem to be slower. The > > ping test does confirm this, because here response times are very high. > > As far as I can remember the wget download rate was a bit slower than > > 2.6.21.1 or 2.6.22-rc3 till it stalled. > > I would expect it to be someting like the other two kernels. The two > > problems I see are the high ping times and the fact that the card stopp= ed > > working. > > > > I don't know why the iperf results are so different from my personal > > experience. I guess the fact that I get so bad results with 2.6.21.1 and > > 2.6.22-rc3 is that iperf does something that causes the system to be > > extremely slow and thus degrading performance. This could be a bug > > somewhere in the b44 driver of 2.6.21.1 and 2.6.22-RC3 that has > > unintended been fixed by the ssb switch, but that's only a roughly gues= s. > > Ok. I guess (Yes I do :D) that there is an IRQ storm or something like > that, because you say that your system is becoming very slow and > unresponsive. It sounds like an IRQ is not ACKed correctly and so keeps > triggering and stalling the system. I'll take a look at a few diffs... > Do you see significant differences in the "hi" and/or "si" times in top? > Do you see a significant difference in the /proc/interrupts count. For > example that the kernel that works worse generates 10 times the IRQ count > for the same amount of data. ok, here are the results: Using 2.6.22-rc3 I get lot's of hi during TX and lots of hi and si during R= X. Using 2.6.22-rc3-mm1 hi and si are significantly lower. It's difficult to give absolute numbers, because top refreshes very slow, b= ut=20 with 2.6.22-rc3 hi is about 30% during TX and RX and si is 0% during TX and= =20 50% during RX. With Using 2.6.22-rc3-mm1 hi is 0% during TX and 0.3% during= =20 RX and si is 10% during TX and 0% during RX. When I do the same test on both kernels I get about 10 times (yes, it's rea= lly=20 about ten times like in your example) more interrupts with 2.6.22-rc3 than= =20 with 2.6.22-rc3-mm1. An additional thing I noticed it that it's not the BCM4401 card that stops= =20 working but my e100 card. If I take the e100 card down and up again the=20 connection is working again, so the BCM4401 doesn't have a "stops working"= =20 bug for me. Maxi --nextPart13571105.gMBMrhRZdQ Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBGWfwrOimwv528XGERAiRQAKCppkNe/vGsseEZc7dhV9Bi37kVFwCgi/hH JBquJ1vl8K3Nlo24tWO/5Pw= =WHFe -----END PGP SIGNATURE----- --nextPart13571105.gMBMrhRZdQ-- -: To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org: More majordomo info at http: //vger.kernel.org/majordomo-info.html