Gentoo Archives: gentoo-amd64

From: Duncan <1i5t5.duncan@×××.net>
To: gentoo-amd64@l.g.o
Subject: [gentoo-amd64] Re: glibc update problem
Date: Thu, 02 Mar 2006 00:10:31
Message-Id: pan.2006.03.02.00.08.33.114122@cox.net
In Reply to: Re: [gentoo-amd64] glibc update problem by Simon Strandman
1 Simon Strandman posted <4405E164.90501@×××××.com>, excerpted below, on
2 Wed, 01 Mar 2006 19:01:08 +0100:
3
4 Robbert Young wrote...
5 >> USE="x86 3dnow X acpi alsa apache2 audiofile avi bitmap-fonts bzip2
6 >> crypt cups dga eds emboss encode exif expat fam fbcon foomaticdb
7 >> fortran gd gdbm gif glut gpm gstreamer gtk gtk2 imagemagick imlib ipv6
8 >> java jikes jpeg junit lcms libg++ libwww mad mailwrapper mhash mikmod
9 >> mmx mng mozilla mp3 mpeg mysql ncurses nptl ogg oggvorbis opengl pam
10 >> pcre pdflib png python quicktime readline samba sdl slang spell sse
11 >> ssl tcpd tetex tiff truetype truetype-fonts type1-fonts udev
12 >> userlocales vorbis xml xml2 xmms xv zlib userland_GNU kernel_linux
13 >> elibc_glibc"
14 >>
15 > 1. Check you RAM with memtest86+.
16
17 Excellent advice, but it won't catch all errors, particularly bus errors
18 that happen only under stress. I know, as I have just such a problem
19 here. After a BIOS came out that had memory speed tweaking, I reduced the
20 speed from the rated 200 (ddr to 400=pc3200) to 183 (ddr to 366, pc3000)
21 and it's now rock-stable, as Linux /should/ be.
22
23 Of course, an insufficient power supply is the next candidate in the
24 hardware failure realm.
25
26 > 2. Drop your CFLAGS to "-march=opteron -O2 -pipe". Extreme CFLAGS wont
27 > improve your performance anyway and I'm a bit suprised you're using such
28 > CFLAGS on a server.
29
30 Well, it /is/ glibc we are talking, and if you check the glibc ebuild, it
31 strips virtually all flags /other/ than the above "-march=opteron -O2
32 -pipe". Thus, in this particular case, unless the ebuild itself has been
33 hacked to kill that strip, I don't believe this is the problem.
34
35 On most ebuilds it could be. You are absolutely right on that, as most
36 don't stripflags to such a small subset. Also see below.
37
38 > 3. You aren't supposed to use a x86 profile on a x86_64-pc-linux-gnu
39 > system. Change to an amd64 profile instead.
40
41 If the issue isn't purely hardware, I'd lay money on this. glibc in
42 particular is not something one wants to be compiling toward the wrong
43 arch. It could very easily be a section of 32-bit hand-tuned assembly,
44 that the compiler is trying to unite with a 64-bit overall glibc. That
45 *WILL* produce problems.
46
47 In addition, flags like 3dnow and mmx (just tried to write xmms =8^) are
48 masked on amd64, because they tend to invoke 32-bit only assembly code.
49 amd64 has those by default, so no need for those USE flags. As I
50 mentioned, however, it's not likely that such is the problem with glibc,
51 given its stripflags. That's anyway on amd64. It's possible they still
52 get thru on the bastardized amd64 system but x86 profile we see here.
53
54 --
55 Duncan - List replies preferred. No HTML msgs.
56 "Every nonfree program has a lord, a master --
57 and if you use the program, he is your master." Richard Stallman in
58 http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html
59
60
61 --
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