On Tue, Jul 15, 2008 at 06:07:40PM -0700, Jay Lan wrote: > Are there known problems if you boot up kdump kernel with > multipl cpus? > I had run into one issue and that was some system would get reset and jump to BIOS. The reason was that kdump kernel can boot on a non-boot cpu. When it tries to bring up other cpus it sends INIT and a non-boot cpu sending INIT to "boot" cpu was not acceptable (as per intel documentation) and it re-initialized the system. I am not sure how many systems are affected with this behavior. Hence the reason for using maxcpus=1. > It takes unacceptably long time to run makedumpfile in > saving dump at a huge memory system. In my testing it > took 16hr25min to run create_dump_bitmap() on a 1TB system. > Pfn's are processed sequentially with single cpu. We > certainly can use multipl cpus here ;) This is certainly very long time. How much memory have you reserved for kdump kernel? I had run some tests on a x86_64 128GB RAM system and it took me 4 minutes to filter and save the core (maximum filtering level of 31). I had reserved 128MB of memory for kdump kernel. I think something else is seriously wrong here. 1 TB is almost 10 times of 128GM and even if time scales linearly it should not take more than 40mins. You need to dive deeper to find out what is taking so much of time. CCing kenichi. Thanks Vivek
