| Message ID | 20200727075532.30058-1-srikar@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Optimization to improve cpu online/offline on Powerpc | expand |
On Mon, Jul 27, 2020 at 01:25:25PM +0530, Srikar Dronamraju wrote: > Anton reported that his 4096 cpu (1024 cores in a socket) was taking too > long to boot. He also analyzed that most of the time was being spent on > updating cpu_core_mask. > > Here are some optimizations and fixes to make ppc64_cpu --smt=8/ppc64_cpu > --smt=1 run faster and hence boot the kernel also faster. > > Its based on top of my v4 coregroup support patchset. > http://lore.kernel.org/lkml/20200727053230.19753-1-srikar@linux.vnet.ibm.com/t/#u > > The first two patches should solve Anton's immediate problem. > On the unofficial patches, Anton reported that the boot time came from 30 > mins to 6 seconds. (Basically a high core count in a single socket > configuration). Satheesh also reported similar numbers. > > The rest are simple cleanups/optimizations. > > Since cpu_core_mask is an exported symbol for a long duration, lets retain > as a snapshot of cpumask_of_node. boot tested on P9 KVM guest. without this series: # dmesg|grep smp [ 0.066624] smp: Bringing up secondary CPUs ... [ 347.521264] smp: Brought up 1 node, 2048 CPUs with this series: # dmesg|grep smp [ 0.067744] smp: Bringing up secondary CPUs ... [ 5.416910] smp: Brought up 1 node, 2048 CPUs Tested-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com> Regards, -Satheesh > > Architecture: ppc64le > Byte Order: Little Endian > CPU(s): 160 > On-line CPU(s) list: 0-159 > Thread(s) per core: 4 > Core(s) per socket: 20 > Socket(s): 2 > NUMA node(s): 2 > Model: 2.2 (pvr 004e 1202) > Model name: POWER9, altivec supported > CPU max MHz: 3800.0000 > CPU min MHz: 2166.0000 > L1d cache: 32K > L1i cache: 32K > L2 cache: 512K > L3 cache: 10240K > NUMA node0 CPU(s): 0-79 > NUMA node8 CPU(s): 80-159 > > without patch (powerpc/next) > [ 0.099347] smp: Bringing up secondary CPUs ... > [ 0.832513] smp: Brought up 2 nodes, 160 CPUs > > with powerpc/next + coregroup support patchset > [ 0.099241] smp: Bringing up secondary CPUs ... > [ 0.835627] smp: Brought up 2 nodes, 160 CPUs > > with powerpc/next + coregroup + this patchset > [ 0.097232] smp: Bringing up secondary CPUs ... > [ 0.528457] smp: Brought up 2 nodes, 160 CPUs > > x ppc64_cpu --smt=1 > + ppc64_cpu --smt=4 > > without patch > N Min Max Median Avg Stddev > x 100 11.82 17.06 14.01 14.05 1.2665247 > + 100 12.25 16.59 13.86 14.1143 1.164293 > > with patch > N Min Max Median Avg Stddev > x 100 12.68 16.15 14.24 14.238 0.75489246 > + 100 12.93 15.85 14.35 14.2897 0.60041813 > > Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> > Cc: LKML <linux-kernel@vger.kernel.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Nicholas Piggin <npiggin@gmail.com> > Cc: Anton Blanchard <anton@ozlabs.org> > Cc: Oliver O'Halloran <oohall@gmail.com> > Cc: Nathan Lynch <nathanl@linux.ibm.com> > Cc: Michael Neuling <mikey@neuling.org> > Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com> > Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Valentin Schneider <valentin.schneider@arm.com> > > Srikar Dronamraju (7): > powerpc/topology: Update topology_core_cpumask > powerpc/smp: Stop updating cpu_core_mask > powerpc/smp: Remove get_physical_package_id > powerpc/smp: Optimize remove_cpu_from_masks > powerpc/smp: Limit cpus traversed to within a node. > powerpc/smp: Stop passing mask to update_mask_by_l2 > powerpc/smp: Depend on cpu_l1_cache_map when adding cpus > > arch/powerpc/include/asm/smp.h | 5 -- > arch/powerpc/include/asm/topology.h | 7 +-- > arch/powerpc/kernel/smp.c | 79 +++++++++-------------------- > 3 files changed, 24 insertions(+), 67 deletions(-) > > -- > 2.17.1 >
Anton reported that his 4096 cpu (1024 cores in a socket) was taking too long to boot. He also analyzed that most of the time was being spent on updating cpu_core_mask. Here are some optimizations and fixes to make ppc64_cpu --smt=8/ppc64_cpu --smt=1 run faster and hence boot the kernel also faster. Its based on top of my v4 coregroup support patchset. http://lore.kernel.org/lkml/20200727053230.19753-1-srikar@linux.vnet.ibm.com/t/#u The first two patches should solve Anton's immediate problem. On the unofficial patches, Anton reported that the boot time came from 30 mins to 6 seconds. (Basically a high core count in a single socket configuration). Satheesh also reported similar numbers. The rest are simple cleanups/optimizations. Since cpu_core_mask is an exported symbol for a long duration, lets retain as a snapshot of cpumask_of_node. Architecture: ppc64le Byte Order: Little Endian CPU(s): 160 On-line CPU(s) list: 0-159 Thread(s) per core: 4 Core(s) per socket: 20 Socket(s): 2 NUMA node(s): 2 Model: 2.2 (pvr 004e 1202) Model name: POWER9, altivec supported CPU max MHz: 3800.0000 CPU min MHz: 2166.0000 L1d cache: 32K L1i cache: 32K L2 cache: 512K L3 cache: 10240K NUMA node0 CPU(s): 0-79 NUMA node8 CPU(s): 80-159 without patch (powerpc/next) [ 0.099347] smp: Bringing up secondary CPUs ... [ 0.832513] smp: Brought up 2 nodes, 160 CPUs with powerpc/next + coregroup support patchset [ 0.099241] smp: Bringing up secondary CPUs ... [ 0.835627] smp: Brought up 2 nodes, 160 CPUs with powerpc/next + coregroup + this patchset [ 0.097232] smp: Bringing up secondary CPUs ... [ 0.528457] smp: Brought up 2 nodes, 160 CPUs x ppc64_cpu --smt=1 + ppc64_cpu --smt=4 without patch N Min Max Median Avg Stddev x 100 11.82 17.06 14.01 14.05 1.2665247 + 100 12.25 16.59 13.86 14.1143 1.164293 with patch N Min Max Median Avg Stddev x 100 12.68 16.15 14.24 14.238 0.75489246 + 100 12.93 15.85 14.35 14.2897 0.60041813 Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Cc: LKML <linux-kernel@vger.kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Oliver O'Halloran <oohall@gmail.com> Cc: Nathan Lynch <nathanl@linux.ibm.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com> Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Valentin Schneider <valentin.schneider@arm.com> Srikar Dronamraju (7): powerpc/topology: Update topology_core_cpumask powerpc/smp: Stop updating cpu_core_mask powerpc/smp: Remove get_physical_package_id powerpc/smp: Optimize remove_cpu_from_masks powerpc/smp: Limit cpus traversed to within a node. powerpc/smp: Stop passing mask to update_mask_by_l2 powerpc/smp: Depend on cpu_l1_cache_map when adding cpus arch/powerpc/include/asm/smp.h | 5 -- arch/powerpc/include/asm/topology.h | 7 +-- arch/powerpc/kernel/smp.c | 79 +++++++++-------------------- 3 files changed, 24 insertions(+), 67 deletions(-)