On 5/18/22 7:09 PM, Nicholas Piggin wrote:
CONFIG_VIRT_CPU_ACCOUNTING_GEN under pseries does not implement stolen time accounting. Implement it with the paravirt time accounting option. Signed-off-by: Nicholas Piggin <npig...@gmail.com>
Tested-by: Shrikanth Hegde <sshe...@linux.ibm.com> Patch fails to compile with CONFIG_PARAVIRT=y with below error. In file included from kernel/sched/core.c:81: kernel/sched/sched.h:87:11: fatal error: asm/paravirt_api_clock.h: No such file or directory 87 | # include <asm/paravirt_api_clock.h> compilation terminated. after adding the file, it compiled. Please add the file as well. patch i did. diff --git a/arch/powerpc/include/asm/paravirt_api_clock.h b/arch/powerpc/include/asm/paravirt_api_clock.h new file mode 100644 index 000000000000..65ac7cee0dad --- /dev/null +++ b/arch/powerpc/include/asm/paravirt_api_clock.h @@ -0,0 +1 @@ +#include <asm/paravirt.h> After successful compilation, it was tested on Power10 Shared LPAR. system has two LPAR. we will call first one LPAR1 and second one as LPAR2. Test was carried out in SMT=1. Similar observation was seen in SMT=8 as well. LPAR config header from each LPAR is below. LPAR1 is twice as big as LPAR2. Since Both are sharing the same underlying hardware, work stealing will happen when both the LPAR's are contending for the same resource. LPAR1: type=Shared mode=Uncapped smt=Off lcpu=40 mem=2094637056 kB cpus=40 ent=20.00 LPAR2: type=Shared mode=Uncapped smt=Off lcpu=20 mem=2083908608 kB cpus=40 ent=10.00 mpstat was used to check for the utilization. stress-ng has been used as the workload. Few cases are tested. when the both LPAR are idle there is no steal time. when LPAR1 starts running at 100% which consumes all of the physical resource, steal time starts to get accounted. With LPAR1 running at 100% and LPAR2 starts running, steal time starts increasing. This is as expected. When the LPAR2 Load is increased further, steal time increases further. Case 1: 0% LPAR1; 0% LPAR2 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle all 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.00 0.00 99.95 Case 2: 100% LPAR1; 0% LPAR2 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle all 97.68 0.00 0.00 0.00 0.00 0.00 2.32 0.00 0.00 0.00 Case 3: 100% LPAR1; 50% LPAR2 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle all 86.34 0.00 0.10 0.00 0.00 0.03 13.54 0.00 0.00 0.00 Case 4: 100% LPAR1; 100% LPAR2 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle all 78.54 0.00 0.07 0.00 0.00 0.02 21.36 0.00 0.00 0.00 Case 5: 50% LPAR1; 100% LPAR2 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle all 49.37 0.00 0.00 0.00 0.00 0.00 1.17 0.00 0.00 49.47 Patch is accounting for the steal time and basic tests are holding good. -- Shrikanth Hegde
