On Thu, Mar 15, 2018 at 08:16:32AM -0300, Jani Nikula wrote: > On Wed, 14 Mar 2018, Lucas De Marchi <lucas.demarchi@xxxxxxxxx> wrote: > > Reorder fields so we save 8 bytes per instance: this removes a 4-bytes > > hole after enum intel_dpll_id and a 4-bytes padding. > > Does GCC have anything like the Clang -Wpadded option to warn us about Humn.. I never saw one. > alignment holes and padding? Certainly it would be too noisy to run all > the time anyway, but it seems a bit tedious to have to do this by > hand. We could run it every once in a while to catch the worst > offenders. oh, no. I didn't do this manually. I used pahole (https://git.kernel.org/pub/scm/devel/pahole/pahole.git/) It has even a --reorganize option that should be used with care as some times data locality is more important on big structs. I always use it passing the struct I'm checking, but you can give it just the .o/.ko to analyze all the structs there (possibly with the -H option to filter by number of holes. Doing this on drivers/gpu/drm/i915/i915_debugfs.o for example I find a big offender: struct intel_dp { ... /* size: 2688, cachelines: 42, members: 55 */ /* sum members: 2662, holes: 7, sum holes: 26 */ /* paddings: 2, sum paddings: 8 */ }; Entire output of drm_i915_private for reference: $ pahole -C drm_i915_private drivers/gpu/drm/i915/i915.ko struct drm_i915_private { struct drm_device drm; /* 0 1576 */ /* --- cacheline 24 boundary (1536 bytes) was 40 bytes ago --- */ struct kmem_cache * objects; /* 1576 8 */ struct kmem_cache * vmas; /* 1584 8 */ struct kmem_cache * luts; /* 1592 8 */ /* --- cacheline 25 boundary (1600 bytes) --- */ struct kmem_cache * requests; /* 1600 8 */ struct kmem_cache * dependencies; /* 1608 8 */ struct kmem_cache * priorities; /* 1616 8 */ struct intel_device_infoconst info; /* 1624 184 */ /* --- cacheline 28 boundary (1792 bytes) was 16 bytes ago --- */ struct intel_driver_caps caps; /* 1808 4 */ /* XXX 4 bytes hole, try to pack */ struct resource dsm; /* 1816 64 */ /* --- cacheline 29 boundary (1856 bytes) was 24 bytes ago --- */ struct resource dsm_reserved; /* 1880 64 */ /* --- cacheline 30 boundary (1920 bytes) was 24 bytes ago --- */ resource_size_t stolen_usable_size; /* 1944 8 */ void * regs; /* 1952 8 */ struct intel_uncore uncore; /* 1960 952 */ /* --- cacheline 45 boundary (2880 bytes) was 32 bytes ago --- */ struct i915_virtual_gpu vgpu; /* 2912 8 */ struct intel_gvt * gvt; /* 2920 8 */ struct intel_wopcm wopcm; /* 2928 12 */ /* XXX 4 bytes hole, try to pack */ /* --- cacheline 46 boundary (2944 bytes) --- */ struct intel_huc huc; /* 2944 72 */ /* --- cacheline 47 boundary (3008 bytes) was 8 bytes ago --- */ struct intel_guc guc; /* 3016 792 */ /* --- cacheline 59 boundary (3776 bytes) was 32 bytes ago --- */ struct intel_csr csr; /* 3808 136 */ /* --- cacheline 61 boundary (3904 bytes) was 40 bytes ago --- */ struct intel_gmbus gmbus[13]; /* 3944 14144 */ /* --- cacheline 282 boundary (18048 bytes) was 40 bytes ago --- */ struct mutex gmbus_mutex; /* 18088 32 */ /* --- cacheline 283 boundary (18112 bytes) was 8 bytes ago --- */ uint32_t gpio_mmio_base; /* 18120 4 */ uint32_t mipi_mmio_base; /* 18124 4 */ uint32_t psr_mmio_base; /* 18128 4 */ uint32_t pps_mmio_base; /* 18132 4 */ wait_queue_head_t gmbus_wait_queue; /* 18136 24 */ struct pci_dev * bridge_dev; /* 18160 8 */ struct intel_engine_cs * engine[8]; /* 18168 64 */ /* --- cacheline 284 boundary (18176 bytes) was 56 bytes ago --- */ struct i915_gem_context * kernel_context; /* 18232 8 */ /* --- cacheline 285 boundary (18240 bytes) --- */ struct i915_gem_context * preempt_context; /* 18240 8 */ struct intel_engine_cs * engine_class[5][4]; /* 18248 160 */ /* --- cacheline 287 boundary (18368 bytes) was 40 bytes ago --- */ struct drm_dma_handle * status_page_dmah; /* 18408 8 */ struct resource mch_res; /* 18416 64 */ /* --- cacheline 288 boundary (18432 bytes) was 48 bytes ago --- */ spinlock_t irq_lock; /* 18480 4 */ bool display_irqs_enabled; /* 18484 1 */ /* XXX 3 bytes hole, try to pack */ struct pm_qos_request pm_qos; /* 18488 136 */ /* --- cacheline 291 boundary (18624 bytes) --- */ struct mutex sb_lock; /* 18624 32 */ union { u32 irq_mask; /* 4 */ u32 de_irq_mask[3]; /* 12 */ }; /* 18656 12 */ u32 gt_irq_mask; /* 18668 4 */ u32 pm_imr; /* 18672 4 */ u32 pm_ier; /* 18676 4 */ u32 pm_rps_events; /* 18680 4 */ u32 pm_guc_events; /* 18684 4 */ /* --- cacheline 292 boundary (18688 bytes) --- */ u32 pipestat_irq_mask[3]; /* 18688 12 */ /* XXX 4 bytes hole, try to pack */ struct i915_hotplug hotplug; /* 18704 408 */ /* --- cacheline 298 boundary (19072 bytes) was 40 bytes ago --- */ struct intel_fbc fbc; /* 19112 448 */ /* --- cacheline 305 boundary (19520 bytes) was 40 bytes ago --- */ struct i915_drrs drrs; /* 19560 144 */ /* --- cacheline 307 boundary (19648 bytes) was 56 bytes ago --- */ struct intel_opregion opregion; /* 19704 112 */ /* --- cacheline 309 boundary (19776 bytes) was 40 bytes ago --- */ struct intel_vbt_data vbt; /* 19816 384 */ /* --- cacheline 315 boundary (20160 bytes) was 40 bytes ago --- */ bool preserve_bios_swizzle; /* 20200 1 */ /* XXX 7 bytes hole, try to pack */ struct intel_overlay * overlay; /* 20208 8 */ struct mutex backlight_lock; /* 20216 32 */ /* --- cacheline 316 boundary (20224 bytes) was 24 bytes ago --- */ bool no_aux_handshake; /* 20248 1 */ /* XXX 7 bytes hole, try to pack */ struct mutex pps_mutex; /* 20256 32 */ /* --- cacheline 317 boundary (20288 bytes) --- */ struct drm_i915_fence_reg fence_regs[32]; /* 20288 1536 */ /* --- cacheline 341 boundary (21824 bytes) --- */ int num_fence_regs; /* 21824 4 */ unsigned int fsb_freq; /* 21828 4 */ unsigned int mem_freq; /* 21832 4 */ unsigned int is_ddr3; /* 21836 4 */ unsigned int skl_preferred_vco_freq; /* 21840 4 */ unsigned int max_cdclk_freq; /* 21844 4 */ unsigned int max_dotclk_freq; /* 21848 4 */ unsigned int rawclk_freq; /* 21852 4 */ unsigned int hpll_freq; /* 21856 4 */ unsigned int fdi_pll_freq; /* 21860 4 */ unsigned int czclk_freq; /* 21864 4 */ struct { struct intel_cdclk_state logical; /* 21868 20 */ struct intel_cdclk_state actual; /* 21888 20 */ struct intel_cdclk_state hw; /* 21908 20 */ } cdclk; /* 21868 60 */ /* --- cacheline 342 boundary (21888 bytes) was 40 bytes ago --- */ struct workqueue_struct * wq; /* 21928 8 */ struct workqueue_struct * modeset_wq; /* 21936 8 */ struct drm_i915_display_funcs display; /* 21944 192 */ /* --- cacheline 345 boundary (22080 bytes) was 56 bytes ago --- */ enum intel_pch pch_type; /* 22136 4 */ short unsigned int pch_id; /* 22140 2 */ /* XXX 2 bytes hole, try to pack */ /* --- cacheline 346 boundary (22144 bytes) --- */ long unsigned int quirks; /* 22144 8 */ enum modeset_restore modeset_restore; /* 22152 4 */ /* XXX 4 bytes hole, try to pack */ struct mutex modeset_restore_lock; /* 22160 32 */ struct drm_atomic_state * modeset_restore_state; /* 22192 8 */ struct drm_modeset_acquire_ctx reset_ctx; /* 22200 56 */ /* --- cacheline 347 boundary (22208 bytes) was 48 bytes ago --- */ struct list_head vm_list; /* 22256 16 */ /* --- cacheline 348 boundary (22272 bytes) --- */ struct i915_ggtt ggtt; /* 22272 1880 */ /* --- cacheline 377 boundary (24128 bytes) was 24 bytes ago --- */ struct i915_gem_mm mm; /* 24152 680 */ /* --- cacheline 388 boundary (24832 bytes) --- */ struct hlist_head mm_structs[128]; /* 24832 1024 */ /* --- cacheline 404 boundary (25856 bytes) --- */ struct mutex mm_lock; /* 25856 32 */ struct intel_ppat ppat; /* 25888 176 */ /* --- cacheline 407 boundary (26048 bytes) was 16 bytes ago --- */ struct intel_crtc * plane_to_crtc_mapping[3]; /* 26064 24 */ struct intel_crtc * pipe_to_crtc_mapping[3]; /* 26088 24 */ /* --- cacheline 408 boundary (26112 bytes) --- */ struct intel_pipe_crc pipe_crc[3]; /* 26112 192 */ /* --- cacheline 411 boundary (26304 bytes) --- */ int num_shared_dpll; /* 26304 4 */ /* XXX 4 bytes hole, try to pack */ struct intel_shared_dpll shared_dplls[6]; /* 26312 720 */ /* --- cacheline 422 boundary (27008 bytes) was 24 bytes ago --- */ const struct intel_dpll_mgr * dpll_mgr; /* 27032 8 */ struct mutex dpll_lock; /* 27040 32 */ /* --- cacheline 423 boundary (27072 bytes) --- */ unsigned int active_crtcs; /* 27072 4 */ int min_cdclk[3]; /* 27076 12 */ u8 min_voltage_level[3]; /* 27088 3 */ /* XXX 1 byte hole, try to pack */ int dpio_phy_iosf_port[2]; /* 27092 8 */ struct i915_workarounds workarounds; /* 27100 228 */ /* --- cacheline 427 boundary (27328 bytes) --- */ struct i915_frontbuffer_tracking fb_tracking; /* 27328 12 */ /* XXX 4 bytes hole, try to pack */ struct intel_atomic_helper atomic_helper; /* 27344 40 */ u16 orig_clock; /* 27384 2 */ bool mchbar_need_disable; /* 27386 1 */ /* XXX 5 bytes hole, try to pack */ /* --- cacheline 428 boundary (27392 bytes) --- */ struct intel_l3_parity l3_parity; /* 27392 56 */ u32 edram_cap; /* 27448 4 */ /* XXX 4 bytes hole, try to pack */ /* --- cacheline 429 boundary (27456 bytes) --- */ struct mutex pcu_lock; /* 27456 32 */ struct intel_gen6_power_mgmt gt_pm; /* 27488 176 */ /* --- cacheline 432 boundary (27648 bytes) was 16 bytes ago --- */ struct intel_ilk_power_mgmt ips; /* 27664 72 */ /* --- cacheline 433 boundary (27712 bytes) was 24 bytes ago --- */ struct i915_power_domains power_domains; /* 27736 208 */ /* --- cacheline 436 boundary (27904 bytes) was 40 bytes ago --- */ struct i915_psr psr; /* 27944 200 */ /* --- cacheline 439 boundary (28096 bytes) was 48 bytes ago --- */ struct i915_gpu_error gpu_error; /* 28144 224 */ /* --- cacheline 443 boundary (28352 bytes) was 16 bytes ago --- */ struct drm_i915_gem_object * vlv_pctx; /* 28368 8 */ struct intel_fbdev * fbdev; /* 28376 8 */ struct work_struct fbdev_suspend_work; /* 28384 32 */ /* --- cacheline 444 boundary (28416 bytes) --- */ struct drm_property * broadcast_rgb_property; /* 28416 8 */ struct drm_property * force_audio_property; /* 28424 8 */ struct i915_audio_component * audio_component; /* 28432 8 */ bool audio_component_registered; /* 28440 1 */ /* XXX 7 bytes hole, try to pack */ struct mutex av_mutex; /* 28448 32 */ /* --- cacheline 445 boundary (28480 bytes) --- */ struct { struct list_head list; /* 28480 16 */ struct llist_head free_list; /* 28496 8 */ struct work_struct free_work; /* 28504 32 */ struct ida hw_ida; /* 28536 16 */ /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ } contexts; /* 28480 72 */ /* --- cacheline 446 boundary (28544 bytes) was 8 bytes ago --- */ u32 fdi_rx_config; /* 28552 4 */ u32 chv_phy_control; /* 28556 4 */ u32 chv_dpll_md[3]; /* 28560 12 */ u32 bxt_phy_grc; /* 28572 4 */ u32 suspend_count; /* 28576 4 */ bool suspended_to_idle; /* 28580 1 */ /* XXX 3 bytes hole, try to pack */ struct i915_suspend_saved_registers regfile; /* 28584 424 */ /* --- cacheline 453 boundary (28992 bytes) was 16 bytes ago --- */ struct vlv_s0ix_state vlv_s0ix_state; /* 29008 260 */ /* --- cacheline 457 boundary (29248 bytes) was 20 bytes ago --- */ enum { I915_SAGV_UNKNOWN = 0, I915_SAGV_DISABLED = 1, I915_SAGV_ENABLED = 2, I915_SAGV_NOT_CONTROLLED = 3, } sagv_status; /* 29268 4 */ struct { uint16_t pri_latency[5]; /* 29272 10 */ uint16_t spr_latency[5]; /* 29282 10 */ uint16_t cur_latency[5]; /* 29292 10 */ uint16_t skl_latency[8]; /* 29302 16 */ union { struct ilk_wm_values hw; /* 56 */ struct skl_wm_values skl_hw; /* 124 */ struct vlv_wm_values vlv; /* 60 */ struct g4x_wm_values g4x; /* 40 */ }; /* 29320 124 */ /* --- cacheline 2 boundary (128 bytes) was 42 bytes ago --- */ uint8_t max_level; /* 29444 1 */ struct mutex wm_mutex; /* 29448 32 */ /* --- cacheline 3 boundary (192 bytes) was 11 bytes ago --- */ bool distrust_bios_wm; /* 29480 1 */ } wm; /* 29272 216 */ /* --- cacheline 460 boundary (29440 bytes) was 48 bytes ago --- */ struct i915_runtime_pm runtime_pm; /* 29488 8 */ struct { bool initialized; /* 29496 1 */ struct kobject * metrics_kobj; /* 29504 8 */ struct ctl_table_header * sysctl_header; /* 29512 8 */ struct mutex metrics_lock; /* 29520 32 */ struct idr metrics_idr; /* 29552 24 */ /* --- cacheline 1 boundary (64 bytes) was 9 bytes ago --- */ struct mutex lock; /* 29576 32 */ struct list_head streams; /* 29608 16 */ struct { struct i915_perf_stream * exclusive_stream; /* 29624 8 */ u32 specific_ctx_id; /* 29632 4 */ struct hrtimer poll_check_timer; /* 29640 64 */ /* --- cacheline 1 boundary (64 bytes) was 12 bytes ago --- */ wait_queue_head_t poll_wq; /* 29704 24 */ bool pollin; /* 29728 1 */ struct ratelimit_state spurious_report_rs; /* 29736 40 */ /* --- cacheline 2 boundary (128 bytes) was 13 bytes ago --- */ bool periodic; /* 29776 1 */ int period_exponent; /* 29780 4 */ struct i915_oa_config test_config; /* 29784 192 */ /* --- cacheline 5 boundary (320 bytes) was 18 bytes ago --- */ struct { struct i915_vma * vma; /* 29976 8 */ u8 * vaddr; /* 29984 8 */ u32 last_ctx_id; /* 29992 4 */ int format; /* 29996 4 */ int format_size; /* 30000 4 */ spinlock_t ptr_lock; /* 30004 4 */ struct { u32 offset; /* 30008 4 */ } tails[2]; /* 30008 8 */ unsigned int aged_tail_idx; /* 30016 4 */ u64 aging_timestamp; /* 30024 8 */ u32 head; /* 30032 4 */ } oa_buffer; /* 29976 64 */ /* --- cacheline 6 boundary (384 bytes) was 18 bytes ago --- */ u32 gen7_latched_oastatus1; /* 30040 4 */ u32 ctx_oactxctrl_offset; /* 30044 4 */ u32 ctx_flexeu0_offset; /* 30048 4 */ u32 gen8_valid_ctx_bit; /* 30052 4 */ struct i915_oa_ops ops; /* 30056 80 */ /* --- cacheline 7 boundary (448 bytes) was 50 bytes ago --- */ const struct i915_oa_format * oa_formats; /* 30136 8 */ } oa; /* 29624 520 */ /* --- cacheline 10 boundary (640 bytes) was 1 bytes ago --- */ } perf; /* 29496 648 */ /* --- cacheline 471 boundary (30144 bytes) --- */ struct { void (*resume)(struct drm_i915_private *); /* 30144 8 */ void (*cleanup_engine)(struct intel_engine_cs *); /* 30152 8 */ struct list_head timelines; /* 30160 16 */ struct i915_gem_timeline global_timeline; /* 30176 992 */ /* --- cacheline 16 boundary (1024 bytes) --- */ u32 active_requests; /* 31168 4 */ bool awake; /* 31172 1 */ unsigned int epoch; /* 31176 4 */ struct delayed_work retire_work; /* 31184 88 */ /* --- cacheline 17 boundary (1088 bytes) was 33 bytes ago --- */ struct delayed_work idle_work; /* 31272 88 */ /* --- cacheline 18 boundary (1152 bytes) was 57 bytes ago --- */ ktime_t last_init_time; /* 31360 8 */ /* --- cacheline 19 boundary (1216 bytes) was 1 bytes ago --- */ } gt; /* 30144 1224 */ /* --- cacheline 490 boundary (31360 bytes) was 8 bytes ago --- */ bool chv_phy_assert[2]; /* 31368 2 */ bool ipc_enabled; /* 31370 1 */ /* XXX 5 bytes hole, try to pack */ struct intel_encoder * av_enc_map[3]; /* 31376 24 */ struct { struct platform_device * platdev; /* 31400 8 */ int irq; /* 31408 4 */ } lpe_audio; /* 31400 16 */ struct i915_pmu pmu; /* 31416 496 */ /* --- cacheline 498 boundary (31872 bytes) was 40 bytes ago --- */ /* size: 31912, cachelines: 499, members: 135 */ /* sum members: 31844, holes: 16, sum holes: 68 */ /* last cacheline: 40 bytes */ }; Lucas De Marchi _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
