Messages in this thread | ![/](/images/icornerl.gif) | | From | Kimmo Sundqvist <> | Date | Wed, 16 Apr 2003 16:29:42 +0300 | Subject | [2.4.20 deb ck4 ck6] Load testing, lotsa segfaults |
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Hello
I have a 1GB RAM, and have tried running multiple copies of cpuburn 1.4's burnBX. This is an Abit VP6 motherboard with VIA chipset, but burnBX stresses it more than the recommended burnMMX. I can see that by overclocking RAM, because then burnBX gives more errors than burnMMX. I currently have the memory set so that I can run 14 burnBX processes for 10 hours without RAM-dependent problems.
To consume lots of memory I use the P option with burnBX. That is 64MB for each burnBX process. I am trying out several different kernels to locate the problem(s). This is a Pentium III 933MHz dual CPU machine. Debian 3.0r1 with XFree86 4.2.1-3, KDE 3.11 or Enlightenment 0.16.5, libc6 2.2.5-14.2, all partitions are ReiserFS noatime, notail.
With Debian's 2.4.20 kernel configured with SMP I've been unable to get any segfault problems to appear. Same when done with KDE, Enlightenment and console only. Therefore I am quite positive this is not a hardware, XFree, KDE or Enlightenment problem.
With 2.4.20-ck6, configured with compressed cache, compressed swap, NO pre-empt and NO SMP, everything goes fine as long as physical memory is not used up. As soon as first sign of swapping should happen, one burnBX segfaults. Soon, after trying to run burnBX many times again, having it always segfault immediately, it also makes kswapd zombie/defunct. Other 12 or 13 burnBX keep running. Some time passes, and other processes start segfaulting randomly.
kernel: EIP: 0010:[_lzo1x_1_do_compress+640/864] Not tainted Call Trace: [lzo1x_1_compress+45/180] [lzo_wrapper_compress+39/60] [compress+31/116] [compress_page+156/632] [compress_clean_page+31/36] [shrink_cache+880/1092] [shrink_caches+47/60] [try_to_free_pages_zone+88/216] [kswapd_balance_pgdat+74/152] [kswapd_balance+26/48] [kswapd+153/188] [kernel_thread+40/56] (So, with this kernel it looks like it's a compressed cache problem)
With 2.4.20-ck4 and 2.4.20-ck6 with SMP and pre-empt, but NO compressed anything, I can run 14 or 15 burnBX processes for a while. Then all processes one by one randomly segfault or stop functioning, and finally I can only switch between virtual consoles and do nothing else. Sometimes the machine keeps swapping (this with ck6) and sometimes it does nothing (this the last time I tried with ck4, and HPT370 required cold boot afterwards).
When things (processes) segfault (or just disappear and cease to exist) under ck4 and ck6, kern.log or syslog have nothing about it.
I could try vanilla 2.4.20 without ck patches, 2.5.67 if I get it to compile, and any of the above with mem=512M to avoid possible highmem problems (all have 4GB highmem and highmem IO configured). No use in trying out different compressed cache configurations, since ck4 and ck6 have problems with and without it.
CONFIG_HIGHMEM4G=y, CONFIG_HIGHMEM=y and CONFIG_HIGHIO=y
I think that a kernel should be able to pass this test to be considered stable. I'll try 2.4.20 unpatched next. And since this is my first post here, tell me if I'm dead wrong about the list's purpose.
-Kimmo Sundqvist - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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