Hi SeongJae, On Thu, 13 Jun 2024 10:46:04 -0700 SeongJae Park <sj@xxxxxxxxxx> wrote: > Hi Honggyu, > > On Thu, 13 Jun 2024 22:20:47 +0900 Honggyu Kim <honggyu.kim@xxxxxx> wrote: > > > There was an RFC IDEA "DAMOS-based Tiered-Memory Management" previously > > posted at [1]. > > > > It says there is no implementation of the demote/promote DAMOS action > > are made. This patch series is about its implementation for physical > > address space so that this scheme can be applied in system wide level. > > > > Changes from RFC v4: > > https://lore.kernel.org/20240512175447.75943-1-sj@xxxxxxxxxx > > 1. Add usage and design documents > > 2. Rename alloc_demote_folio to alloc_migrate_folio > > 3. Add evaluation results with "demotion_enabled" true > > 4. Rebase based on v6.10-rc3 > > I left comments on the new patches for the documentation. > > [...] > > > > Evaluation Results > > ================== > > > > All the result values are normalized to DRAM-only execution time because > > the workload cannot be faster than DRAM-only unless the workload hits > > the peak bandwidth but our redis test doesn't go beyond the bandwidth > > limit. > > > > So the DRAM-only execution time is the ideal result without affected by > > the gap between DRAM and CXL performance difference. The NUMA node > > environment is as follows. > > > > node0 - local DRAM, 512GB with a CPU socket (fast tier) > > node1 - disabled > > node2 - CXL DRAM, 96GB, no CPU attached (slow tier) > > > > The following is the result of generating zipfian distribution to > > redis-server and the numbers are averaged by 50 times of execution. > > > > 1. YCSB zipfian distribution read only workload > > memory pressure with cold memory on node0 with 512GB of local DRAM. > > ====================+================================================+========= > > | cold memory occupied by mmap and memset | > > | 0G 440G 450G 460G 470G 480G 490G 500G | > > ====================+================================================+========= > > Execution time normalized to DRAM-only values | GEOMEAN > > --------------------+------------------------------------------------+--------- > > DRAM-only | 1.00 - - - - - - - | 1.00 > > CXL-only | 1.19 - - - - - - - | 1.19 > > default | - 1.00 1.05 1.08 1.12 1.14 1.18 1.18 | 1.11 > > DAMON tiered | - 1.03 1.03 1.03 1.03 1.03 1.07 *1.05 | 1.04 > > DAMON lazy | - 1.04 1.03 1.04 1.05 1.06 1.06 *1.06 | 1.05 > > ====================+================================================+========= > > CXL usage of redis-server in GB | AVERAGE > > --------------------+------------------------------------------------+--------- > > DRAM-only | 0.0 - - - - - - - | 0.0 > > CXL-only | 51.4 - - - - - - - | 51.4 > > default | - 0.6 10.6 20.5 30.5 40.5 47.6 50.4 | 28.7 > > DAMON tiered | - 0.6 0.5 0.4 0.7 0.8 7.1 5.6 | 2.2 > > DAMON lazy | - 0.5 3.0 4.5 5.4 6.4 9.4 9.1 | 5.5 > > ====================+================================================+========= > > > > Each test result is based on the exeuction environment as follows. > > Nit. s/exeuction/execution/ Thanks. Fixed it. > [...] > > In summary, the evaluation results show that DAMON memory management > > with DAMOS_MIGRATE_{HOT,COLD} actions reduces the performance slowdown > > compared to the "default" memory policy from 11% to 3~5% when the system > > runs with high memory pressure on its fast tier DRAM nodes. > > > > Having these DAMOS_MIGRATE_HOT and DAMOS_MIGRATE_COLD actions can make > > tiered memory systems run more efficiently under high memory pressures. > > Thank you very much for continuing this great work. > > Other than trivial comments on documentation patches and the above typo, I have > no particular concern on this patchset. I'm looking forward to the next > version. I have addressed all your comments and resent v6 again. Please have a look again. https://lore.kernel.org/20240614030010.751-1-honggyu.kim@xxxxxx Thanks very much for your review! Thanks, Honggyu > > Thanks, > SJ > [...]
