KSM 的 CPU 使用率一直处于 100%，这让我相信我需要优化配置/etc/ksmtuned.conf，但我不确定该如何为这台机器设置它。从上面的屏幕截图中可以看到，KSM 共享目前为 170GB，似乎不想再高于这个数字了。我创建了测试虚拟机，使用了 100% 的 RAM，然后停止了测试程序，直到我关闭虚拟机后，Proxmox RAM 使用率才恢复。
我如何优化配置并在需要时允许 ksmd 使用高达 500％ 的 CPU 功率（5 CPU）？
watch cat /sys/kernel/mm/ksm/pages_sharing- 回报（并且不会大幅增加）：
44698138
/etc/ksmtuned.conf- 包含
# Configuration file for ksmtuned.
# How long ksmtuned should sleep between tuning adjustments
# KSM_MONITOR_INTERVAL=60
# Millisecond sleep between ksm scans for 16Gb server.
# Smaller servers sleep more, bigger sleep less.
# KSM_SLEEP_MSEC=100
KSM_THRES_COEF=70
# KSM_NPAGES_BOOST=300
# KSM_NPAGES_DECAY=-50
# KSM_NPAGES_MIN=64
# KSM_NPAGES_MAX=1250
# KSM_THRES_COEF=20
# KSM_THRES_CONST=2048
# uncomment the following if you want ksmtuned debug info
LOGFILE=/var/log/ksmtuned
DEBUG=1
我也在使用 ZFS RAID 10
/etc/modprobe.d/zfs.conf- 包含
#Max Ram Used by ZFS - 64GB
options zfs zfs_arc_max=68719476736
#Min Ram Used by ZFS - 20GB
options zfs zfs_arc_min=21474836480
arc_summary- 退货
------------------------------------------------------------------------
ZFS Subsystem Report Wed May 26 13:21:14 2021
Linux 5.4.114-1-pve 2.0.4-pve1
Machine: ns31407416 (x86_64) 2.0.4-pve1
ARC status: HEALTHY
Memory throttle count: 0
ARC size (current): 98.6 % 63.1 GiB
Target size (adaptive): 100.0 % 64.0 GiB
Min size (hard limit): 31.2 % 20.0 GiB
Max size (high water): 3:1 64.0 GiB
Most Frequently Used (MFU) cache size: 19.5 % 11.3 GiB
Most Recently Used (MRU) cache size: 80.5 % 46.6 GiB
Metadata cache size (hard limit): 75.0 % 48.0 GiB
Metadata cache size (current): 14.4 % 6.9 GiB
Dnode cache size (hard limit): 10.0 % 4.8 GiB
Dnode cache size (current): 0.2 % 11.6 MiB
ARC hash breakdown:
Elements max: 16.9M
Elements current: 81.8 % 13.8M
Collisions: 212.2M
Chain max: 7
Chains: 663.6k
ARC misc:
Deleted: 533.3M
Mutex misses: 49.6k
Eviction skips: 21.5k
ARC total accesses (hits + misses): 4.0G
Cache hit ratio: 86.5 % 3.5G
Cache miss ratio: 13.5 % 542.5M
Actual hit ratio (MFU + MRU hits): 86.0 % 3.4G
Data demand efficiency: 53.9 % 1.1G
Data prefetch efficiency: 40.0 % 52.8M
Cache hits by cache type:
Most frequently used (MFU): 80.9 % 2.8G
Most recently used (MRU): 18.6 % 644.4M
Most frequently used (MFU) ghost: 1.4 % 48.6M
Most recently used (MRU) ghost: 0.1 % 4.2M
Cache hits by data type:
Demand data: 17.1 % 593.8M
Demand prefetch data: 0.6 % 21.1M
Demand metadata: 82.2 % 2.8G
Demand prefetch metadata: < 0.1 % 962.6k
Cache misses by data type:
Demand data: 93.8 % 508.6M
Demand prefetch data: 5.8 % 31.7M
Demand metadata: 0.4 % 2.0M
Demand prefetch metadata: < 0.1 % 198.6k
DMU prefetch efficiency: 252.5M
Hit ratio: 9.8 % 24.7M
Miss ratio: 90.2 % 227.8M
L2ARC not detected, skipping section
Solaris Porting Layer (SPL):
spl_hostid 0
spl_hostid_path /etc/hostid
spl_kmem_alloc_max 1048576
spl_kmem_alloc_warn 65536
spl_kmem_cache_kmem_threads 4
spl_kmem_cache_magazine_size 0
spl_kmem_cache_max_size 32
spl_kmem_cache_obj_per_slab 8
spl_kmem_cache_reclaim 0
spl_kmem_cache_slab_limit 16384
spl_max_show_tasks 512
spl_panic_halt 0
spl_schedule_hrtimeout_slack_us 0
spl_taskq_kick 0
spl_taskq_thread_bind 0
spl_taskq_thread_dynamic 1
spl_taskq_thread_priority 1
spl_taskq_thread_sequential 4
Tunables:
dbuf_cache_hiwater_pct 10
dbuf_cache_lowater_pct 10
dbuf_cache_max_bytes 18446744073709551615
dbuf_cache_shift 5
dbuf_metadata_cache_max_bytes 18446744073709551615
dbuf_metadata_cache_shift 6
dmu_object_alloc_chunk_shift 7
dmu_prefetch_max 134217728
ignore_hole_birth 1
l2arc_feed_again 1
l2arc_feed_min_ms 200
l2arc_feed_secs 1
l2arc_headroom 2
l2arc_headroom_boost 200
l2arc_meta_percent 33
l2arc_mfuonly 0
l2arc_noprefetch 1
l2arc_norw 0
l2arc_rebuild_blocks_min_l2size 1073741824
l2arc_rebuild_enabled 1
l2arc_trim_ahead 0
l2arc_write_boost 8388608
l2arc_write_max 8388608
metaslab_aliquot 524288
metaslab_bias_enabled 1
metaslab_debug_load 0
metaslab_debug_unload 0
metaslab_df_max_search 16777216
metaslab_df_use_largest_segment 0
metaslab_force_ganging 16777217
metaslab_fragmentation_factor_enabled 1
metaslab_lba_weighting_enabled 1
metaslab_preload_enabled 1
metaslab_unload_delay 32
metaslab_unload_delay_ms 600000
send_holes_without_birth_time 1
spa_asize_inflation 24
spa_config_path /etc/zfs/zpool.cache
spa_load_print_vdev_tree 0
spa_load_verify_data 1
spa_load_verify_metadata 1
spa_load_verify_shift 4
spa_slop_shift 5
vdev_file_logical_ashift 9
vdev_file_physical_ashift 9
vdev_removal_max_span 32768
vdev_validate_skip 0
zap_iterate_prefetch 1
zfetch_array_rd_sz 1048576
zfetch_max_distance 8388608
zfetch_max_idistance 67108864
zfetch_max_streams 8
zfetch_min_sec_reap 2
zfs_abd_scatter_enabled 1
zfs_abd_scatter_max_order 10
zfs_abd_scatter_min_size 1536
zfs_admin_snapshot 0
zfs_allow_redacted_dataset_mount 0
zfs_arc_average_blocksize 8192
zfs_arc_dnode_limit 0
zfs_arc_dnode_limit_percent 10
zfs_arc_dnode_reduce_percent 10
zfs_arc_evict_batch_limit 10
zfs_arc_eviction_pct 200
zfs_arc_grow_retry 0
zfs_arc_lotsfree_percent 10
zfs_arc_max 68719476736
zfs_arc_meta_adjust_restarts 4096
zfs_arc_meta_limit 0
zfs_arc_meta_limit_percent 75
zfs_arc_meta_min 0
zfs_arc_meta_prune 10000
zfs_arc_meta_strategy 1
zfs_arc_min 21474836480
zfs_arc_min_prefetch_ms 0
zfs_arc_min_prescient_prefetch_ms 0
zfs_arc_p_dampener_disable 1
zfs_arc_p_min_shift 0
zfs_arc_pc_percent 0
zfs_arc_shrink_shift 0
zfs_arc_shrinker_limit 10000
zfs_arc_sys_free 0
zfs_async_block_max_blocks 18446744073709551615
zfs_autoimport_disable 1
zfs_checksum_events_per_second 20
zfs_commit_timeout_pct 5
zfs_compressed_arc_enabled 1
zfs_condense_indirect_commit_entry_delay_ms 0
zfs_condense_indirect_vdevs_enable 1
zfs_condense_max_obsolete_bytes 1073741824
zfs_condense_min_mapping_bytes 131072
zfs_dbgmsg_enable 1
zfs_dbgmsg_maxsize 4194304
zfs_dbuf_state_index 0
zfs_ddt_data_is_special 1
zfs_deadman_checktime_ms 60000
zfs_deadman_enabled 1
zfs_deadman_failmode wait
zfs_deadman_synctime_ms 600000
zfs_deadman_ziotime_ms 300000
zfs_dedup_prefetch 0
zfs_delay_min_dirty_percent 60
zfs_delay_scale 500000
zfs_delete_blocks 20480
zfs_dirty_data_max 4294967296
zfs_dirty_data_max_max 4294967296
zfs_dirty_data_max_max_percent 25
zfs_dirty_data_max_percent 10
zfs_dirty_data_sync_percent 20
zfs_disable_ivset_guid_check 0
zfs_dmu_offset_next_sync 0
zfs_expire_snapshot 300
zfs_fallocate_reserve_percent 110
zfs_flags 0
zfs_free_bpobj_enabled 1
zfs_free_leak_on_eio 0
zfs_free_min_time_ms 1000
zfs_history_output_max 1048576
zfs_immediate_write_sz 32768
zfs_initialize_chunk_size 1048576
zfs_initialize_value 16045690984833335022
zfs_keep_log_spacemaps_at_export 0
zfs_key_max_salt_uses 400000000
zfs_livelist_condense_new_alloc 0
zfs_livelist_condense_sync_cancel 0
zfs_livelist_condense_sync_pause 0
zfs_livelist_condense_zthr_cancel 0
zfs_livelist_condense_zthr_pause 0
zfs_livelist_max_entries 500000
zfs_livelist_min_percent_shared 75
zfs_lua_max_instrlimit 100000000
zfs_lua_max_memlimit 104857600
zfs_max_async_dedup_frees 100000
zfs_max_log_walking 5
zfs_max_logsm_summary_length 10
zfs_max_missing_tvds 0
zfs_max_nvlist_src_size 0
zfs_max_recordsize 1048576
zfs_metaslab_fragmentation_threshold 70
zfs_metaslab_max_size_cache_sec 3600
zfs_metaslab_mem_limit 75
zfs_metaslab_segment_weight_enabled 1
zfs_metaslab_switch_threshold 2
zfs_mg_fragmentation_threshold 95
zfs_mg_noalloc_threshold 0
zfs_min_metaslabs_to_flush 1
zfs_multihost_fail_intervals 10
zfs_multihost_history 0
zfs_multihost_import_intervals 20
zfs_multihost_interval 1000
zfs_multilist_num_sublists 0
zfs_no_scrub_io 0
zfs_no_scrub_prefetch 0
zfs_nocacheflush 0
zfs_nopwrite_enabled 1
zfs_object_mutex_size 64
zfs_obsolete_min_time_ms 500
zfs_override_estimate_recordsize 0
zfs_pd_bytes_max 52428800
zfs_per_txg_dirty_frees_percent 5
zfs_prefetch_disable 0
zfs_read_history 0
zfs_read_history_hits 0
zfs_rebuild_max_segment 1048576
zfs_reconstruct_indirect_combinations_max 4096
zfs_recover 0
zfs_recv_queue_ff 20
zfs_recv_queue_length 16777216
zfs_recv_write_batch_size 1048576
zfs_removal_ignore_errors 0
zfs_removal_suspend_progress 0
zfs_remove_max_segment 16777216
zfs_resilver_disable_defer 0
zfs_resilver_min_time_ms 3000
zfs_scan_checkpoint_intval 7200
zfs_scan_fill_weight 3
zfs_scan_ignore_errors 0
zfs_scan_issue_strategy 0
zfs_scan_legacy 0
zfs_scan_max_ext_gap 2097152
zfs_scan_mem_lim_fact 20
zfs_scan_mem_lim_soft_fact 20
zfs_scan_strict_mem_lim 0
zfs_scan_suspend_progress 0
zfs_scan_vdev_limit 4194304
zfs_scrub_min_time_ms 1000
zfs_send_corrupt_data 0
zfs_send_no_prefetch_queue_ff 20
zfs_send_no_prefetch_queue_length 1048576
zfs_send_queue_ff 20
zfs_send_queue_length 16777216
zfs_send_unmodified_spill_blocks 1
zfs_slow_io_events_per_second 20
zfs_spa_discard_memory_limit 16777216
zfs_special_class_metadata_reserve_pct 25
zfs_sync_pass_deferred_free 2
zfs_sync_pass_dont_compress 8
zfs_sync_pass_rewrite 2
zfs_sync_taskq_batch_pct 75
zfs_trim_extent_bytes_max 134217728
zfs_trim_extent_bytes_min 32768
zfs_trim_metaslab_skip 0
zfs_trim_queue_limit 10
zfs_trim_txg_batch 32
zfs_txg_history 100
zfs_txg_timeout 5
zfs_unflushed_log_block_max 262144
zfs_unflushed_log_block_min 1000
zfs_unflushed_log_block_pct 400
zfs_unflushed_max_mem_amt 1073741824
zfs_unflushed_max_mem_ppm 1000
zfs_unlink_suspend_progress 0
zfs_user_indirect_is_special 1
zfs_vdev_aggregate_trim 0
zfs_vdev_aggregation_limit 1048576
zfs_vdev_aggregation_limit_non_rotating 131072
zfs_vdev_async_read_max_active 3
zfs_vdev_async_read_min_active 1
zfs_vdev_async_write_active_max_dirty_percent 60
zfs_vdev_async_write_active_min_dirty_percent 30
zfs_vdev_async_write_max_active 10
zfs_vdev_async_write_min_active 2
zfs_vdev_cache_bshift 16
zfs_vdev_cache_max 16384
zfs_vdev_cache_size 0
zfs_vdev_default_ms_count 200
zfs_vdev_default_ms_shift 29
zfs_vdev_initializing_max_active 1
zfs_vdev_initializing_min_active 1
zfs_vdev_max_active 1000
zfs_vdev_max_auto_ashift 16
zfs_vdev_min_auto_ashift 9
zfs_vdev_min_ms_count 16
zfs_vdev_mirror_non_rotating_inc 0
zfs_vdev_mirror_non_rotating_seek_inc 1
zfs_vdev_mirror_rotating_inc 0
zfs_vdev_mirror_rotating_seek_inc 5
zfs_vdev_mirror_rotating_seek_offset 1048576
zfs_vdev_ms_count_limit 131072
zfs_vdev_nia_credit 5
zfs_vdev_nia_delay 5
zfs_vdev_queue_depth_pct 1000
zfs_vdev_raidz_impl cycle [fastest] original scalar sse2 ssse3 avx2
zfs_vdev_read_gap_limit 32768
zfs_vdev_rebuild_max_active 3
zfs_vdev_rebuild_min_active 1
zfs_vdev_removal_max_active 2
zfs_vdev_removal_min_active 1
zfs_vdev_scheduler unused
zfs_vdev_scrub_max_active 3
zfs_vdev_scrub_min_active 1
zfs_vdev_sync_read_max_active 10
zfs_vdev_sync_read_min_active 10
zfs_vdev_sync_write_max_active 10
zfs_vdev_sync_write_min_active 10
zfs_vdev_trim_max_active 2
zfs_vdev_trim_min_active 1
zfs_vdev_write_gap_limit 4096
zfs_vnops_read_chunk_size 1048576
zfs_zevent_cols 80
zfs_zevent_console 0
zfs_zevent_len_max 1536
zfs_zevent_retain_expire_secs 900
zfs_zevent_retain_max 2000
zfs_zil_clean_taskq_maxalloc 1048576
zfs_zil_clean_taskq_minalloc 1024
zfs_zil_clean_taskq_nthr_pct 100
zil_maxblocksize 131072
zil_nocacheflush 0
zil_replay_disable 0
zil_slog_bulk 786432
zio_deadman_log_all 0
zio_dva_throttle_enabled 1
zio_requeue_io_start_cut_in_line 1
zio_slow_io_ms 30000
zio_taskq_batch_pct 75
zvol_inhibit_dev 0
zvol_major 230
zvol_max_discard_blocks 16384
zvol_prefetch_bytes 131072
zvol_request_sync 0
zvol_threads 32
zvol_volmode 1
VDEV cache disabled, skipping section
ZIL committed transactions: 294.4M
Commit requests: 162.6M
Flushes to stable storage: 162.6M
Transactions to SLOG storage pool: 0 Bytes 0
Transactions to non-SLOG storage pool: 8.8 TiB 227.3M
/var/log/ksmtuned-https://pastebin.com/HmDJTyTu
答案1
为了限制ksmd影响，您可以增加KSM_SLEEP_MSEC，或者更好的是，通过减少来限制每次迭代扫描的页面数量KSM_NPAGES_MAX。
因此，一个快速的解决方法是设置KSM_NPAGES_MAX=300
此外，您的KSM_THRES_COEF设置太高了 - 即使有足够的可用 RAM，您也会扫描。考虑将其恢复为20
编辑：如果你想增加CPU 负载ksmd，你可以简单地做相反的事情，增加KSM_NPAGES_MAX和减少KSM_SLEEP_MSEC