From bba7f4d4d0332debe7b3ea6179cf013465f414cf Mon Sep 17 00:00:00 2001 From: Pingfan Liu Date: Fri, 19 Dec 2025 18:42:18 +0800 Subject: [PATCH] powerpc: Set nr_cpus=16 for kdump kernel Resolves: https://issues.redhat.com/browse/RHEL-77215 Upstream: kdump-utils Conflict: manually apply commit 4f7970eefa6cba5d7cebd739718fb947a3fedbad (HEAD -> main, origin/main, origin/HEAD) Author: Sourabh Jain Date: Thu Dec 4 13:51:21 2025 +0530 powerpc: Set nr_cpus=16 for kdump kernel Configure the kdump kernel with nr_cpus=16 to enable multi-threading in the makedumpfile core collector, allowing faster dump collection. Commit d428557fc2b59 ("Use all available CPUs to collect dump") introduced multi-threading support in the core collector. There are two reasons for choosing nr_cpus=16: - Multiple experiments show that optimal performance is achieved when nr_cpus is between 16 and 30. The graph in commit d428557fc2b59 supports this. - nr_cpus=16 is already used for the fadump kernel, so using the same value for kdump to maintain consistency. Signed-off-by: Sourabh Jain Since there is no gen-kdump-sysconfig.sh in RHEL-9 kexec-tools, and the patch just change the nr_cpus from 1 to 16, so apply it manually. Signed-off-by: Pingfan Liu --- kdump.sysconfig.ppc64le | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kdump.sysconfig.ppc64le b/kdump.sysconfig.ppc64le index a2d113f..985fcba 100644 --- a/kdump.sysconfig.ppc64le +++ b/kdump.sysconfig.ppc64le @@ -21,7 +21,7 @@ KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet log_buf_len swio # This variable lets us append arguments to the current kdump commandline # after processed by KDUMP_COMMANDLINE_REMOVE -KDUMP_COMMANDLINE_APPEND="irqpoll nr_cpus=1 noirqdistrib reset_devices cgroup_disable=memory numa=off udev.children-max=2 ehea.use_mcs=0 panic=10 kvm_cma_resv_ratio=0 transparent_hugepage=never novmcoredd hugetlb_cma=0 kfence.sample_interval=0" +KDUMP_COMMANDLINE_APPEND="irqpoll nr_cpus=16 noirqdistrib reset_devices cgroup_disable=memory numa=off udev.children-max=2 ehea.use_mcs=0 panic=10 kvm_cma_resv_ratio=0 transparent_hugepage=never novmcoredd hugetlb_cma=0 kfence.sample_interval=0" # This variable lets us append arguments to fadump (powerpc) capture kernel, # further to the parameters passed via the bootloader.