Hi, On Wed, Feb 23, 2022 at 08:38:03PM +0100, Thomas Zimmermann wrote: > Improve the performance of cfb_imageblit() by manually unrolling > the inner blitting loop and moving some invariants out. The compiler > failed to do this automatically. This change keeps cfb_imageblit() > in sync with sys_imagebit(). > > A microbenchmark measures the average number of CPU cycles > for cfb_imageblit() after a stabilizing period of a few minutes > (i7-4790, FullHD, simpledrm, kernel with debugging). > > cfb_imageblit(), new: 15724 cycles > cfb_imageblit(): old: 30566 cycles > > In the optimized case, cfb_imageblit() is now ~2x faster than before. > > v3: > * fix commit description (Pekka) > > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> This patch causes crashes with arm mainstone, z2, and collie emulations. Reverting it fixes the problem. collie crash log and bisect log attached. Guenter --- 8<--- cut here --- Unable to handle kernel paging request at virtual address e090d000 [e090d000] *pgd=c0c0b811c0c0b811, *pte=c0c0b000, *ppte=00000000 Internal error: Oops: 807 [#1] ARM CPU: 0 PID: 1 Comm: swapper Not tainted 5.17.0-next-20220324 #1 Hardware name: Sharp-Collie PC is at cfb_imageblit+0x58c/0x6e0 LR is at 0x5 pc : [<c040eab0>] lr : [<00000005>] psr: a0000153 sp : e0809958 ip : e090d000 fp : e08099f4 r10: e08099c8 r9 : c0c70600 r8 : ffff6802 r7 : c0c6e000 r6 : 00000000 r5 : e08e7000 r4 : 00000280 r3 : 00000020 r2 : 00000003 r1 : 00000002 r0 : 00000002 Flags: NzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment none Control: 0000717f Table: c0004000 DAC: 00000053 Register r0 information: non-paged memory Register r1 information: non-paged memory Register r2 information: non-paged memory Register r3 information: non-paged memory Register r4 information: non-paged memory Register r5 information: 0-page vmalloc region starting at 0xe08e6000 allocated at dma_common_contiguous_remap+0x94/0xb0 Register r6 information: NULL pointer Register r7 information: non-slab/vmalloc memory Register r8 information: non-paged memory Register r9 information: non-slab/vmalloc memory Register r10 information: 2-page vmalloc region starting at 0xe0808000 allocated at kernel_clone+0x78/0x4e4 Register r11 information: 2-page vmalloc region starting at 0xe0808000 allocated at kernel_clone+0x78/0x4e4 Register r12 information: 0-page vmalloc region starting at 0xe08e6000 allocated at dma_common_contiguous_remap+0x94/0xb0 Process swapper (pid: 1, stack limit = 0x(ptrval)) Stack: (0xe0809958 to 0xe080a000) 9940: 80000153 0000005e 9960: dfb1b424 00000020 00000000 00000000 00000001 00000002 00000003 00000004 9980: dfb1b420 00000000 00000000 00000000 00000000 c067f338 e08099ab 00000026 99a0: 80000153 00000820 007fe178 c07db82c e08099d4 0000003e 00000820 c0e32b00 99c0: 00000006 c07db82c 00000001 c0da1e40 e0809a54 c0e32b00 00000006 00000001 99e0: 00000001 c0c6e000 e0809a34 e08099f8 c040a3f8 c040e530 00000006 00000001 9a00: c0e61920 c0da1e78 00000000 c0e61920 00000000 e0809a54 c06ad89c c0e32b00 9a20: c0da1e00 00000020 e0809acc e0809a38 c040a040 c040a26c e0809a7c 00000140 9a40: 00000002 00000002 00000001 00000007 00000000 00000039 00000001 c0da1e00 9a60: 00000000 00000000 00000000 00000004 00000006 00000007 00000000 00000001 9a80: c06ad89c 00000000 00000000 00000000 00000000 ffffffff ffffffff c07db82c 9aa0: e0809acc c0c0c3c0 c0e32b00 00000007 00000002 00000720 c0409cf0 00000028 9ac0: e0809afc e0809ad0 c040665c c0409cfc 00000000 00000000 c0c0c3c0 c0807584 9ae0: 00000000 00000000 ffffff60 c0c70000 e0809b1c e0809b00 c0439a50 c040656c 9b00: c0c0c3c0 00000000 00000000 00000000 e0809b54 e0809b20 c043a798 c0439a24 9b20: c04095c8 c0c6ff60 00000000 c07db82c e0809b54 c0c0c3c0 c0c6ff60 00000000 9b40: 00000000 ffffff60 e0809ba4 e0809b58 c0407254 c043a5ac e0809b7c e0809b68 9b60: c04145d8 00000000 00000000 00000000 00000720 00000000 00000050 c0c0c3c0 9b80: c0e32b00 c0e61920 00000050 00000028 c0a00df8 00000028 e0809bec e0809ba8 9ba0: c0407748 c0406f04 00000050 00000028 00000050 00000001 c0a02f70 00000000 9bc0: 00000000 c0c0c3c0 c0c0c624 00000000 c0a02f84 0000003e 00000000 c0a03080 9be0: e0809c0c e0809bf0 c0438b10 c040734c c0c0c3c0 c06affbc 00000001 c0a02f84 9c00: e0809c54 e0809c10 c043be28 c0438a80 0000003e 00000001 00000000 c0779d88 9c20: 00000000 00000001 c08075a8 c06affbc 00000000 00000001 00000000 0000003e 9c40: 00000001 c0a02f8c e0809c9c e0809c58 c043c6ec c043bc98 c08075a8 c077c29c 9c60: 00000001 00000000 c0e32b44 c0a03a58 c067f354 c0805a24 c0a00cc8 c0805a24 9c80: 00000000 c07dbabc c0e32da4 fffff000 e0809cb4 e0809ca0 c0405d5c c043c5d4 9ca0: c0a00dac 00000000 e0809cd4 e0809cb8 c0408f48 c0405cfc c0e32b00 00000000 9cc0: c0a00ca8 c0e32b10 e0809d44 e0809cd8 c03ff9e4 c0408e70 c0779a14 00000000 9ce0: c000ea7c 00000000 00000041 00000140 000000f0 00029e01 0000000b 0000001e 9d00: 00000002 00000000 00000005 00000001 00000003 00000000 00000020 c07db82c 9d20: c0e32b00 00000000 c07dfe08 00000004 0000000d 00000000 e0809d84 e0809d48 9d40: c040f550 c03ff7e8 00000004 c077a1b8 c0e32b00 c0180a04 c07dfe18 00000000 9d60: c07dfe18 c0805abc 00000000 00000000 c07cb87c c07cb85c e0809da4 e0809d88 9d80: c045c2c8 c040f228 00000000 c07dfe18 c0805abc 00000000 e0809dc4 e0809da8 9da0: c045a304 c045c288 c07dfe18 c0805abc c07dfe18 00000000 e0809ddc e0809dc8 9dc0: c045a548 c045a250 c0a04c6c 60000153 e0809e04 e0809de0 c045a5f4 c045a4d0 9de0: e0809e04 e0809df0 c07dfe18 c0805abc c045a7d0 c080af60 e0809e24 e0809e08 9e00: c045a860 c045a5b4 00000000 c0805abc c045a7d0 c080af60 e0809e54 e0809e28 9e20: c0458694 c045a7dc c0c30e20 c0c30dec c0c9f3b4 c07db82c c06559b8 c0805abc 9e40: c0e5d340 00000000 e0809e64 e0809e58 c045adf0 c0458620 e0809e8c e0809e68 9e60: c0458fb8 c045addc c0749e14 e0809e78 c0805abc c0c19000 c07bc340 c07a4bc8 9e80: e0809ea4 e0809e90 c045b684 c0458e84 c0818000 c0c19000 e0809eb4 e0809ea8 9ea0: c045d10c c045b614 e0809ec4 e0809eb8 c07bc368 c045d0f8 e0809f4c e0809ec8 9ec0: c07a821c c07bc34c e0809eec e0809ed8 c00374f4 c065f390 c0c427da c07a5600 9ee0: e0809f4c e0809ef0 c00376f4 c07a7448 e0809f03 00000006 00000006 00000000 9f00: 00000000 c07a743c c0793b5c c07a4bc8 00000dc0 c0c427cc c0c427d4 c07db82c 9f20: 00000000 c07d2060 c0c427a0 00000007 c07a4bc8 c0818000 c07cb87c c07cb85c 9f40: e0809f94 e0809f50 c07a85a0 c07a81b0 00000006 00000006 00000000 c07a743c 9f60: c0c19000 0000008c e0809f8c 00000000 c0675804 00000000 00000000 00000000 9f80: 00000000 00000000 e0809fac e0809f98 c067581c c07a842c 00000000 c0675804 9fa0: 00000000 e0809fb0 c0008328 c0675810 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 Backtrace: cfb_imageblit from soft_cursor+0x198/0x1fc r10:c0c6e000 r9:00000001 r8:00000001 r7:00000006 r6:c0e32b00 r5:e0809a54 r4:c0da1e40 soft_cursor from bit_cursor+0x350/0x4fc r10:00000020 r9:c0da1e00 r8:c0e32b00 r7:c06ad89c r6:e0809a54 r5:00000000 r4:c0e61920 bit_cursor from fbcon_cursor+0xfc/0x110 r10:00000028 r9:c0409cf0 r8:00000720 r7:00000002 r6:00000007 r5:c0e32b00 r4:c0c0c3c0 fbcon_cursor from hide_cursor+0x38/0xac r9:c0c70000 r8:ffffff60 r7:00000000 r6:00000000 r5:c0807584 r4:c0c0c3c0 hide_cursor from redraw_screen+0x1f8/0x258 r7:00000000 r6:00000000 r5:00000000 r4:c0c0c3c0 redraw_screen from fbcon_prepare_logo+0x35c/0x448 r8:ffffff60 r7:00000000 r6:00000000 r5:c0c6ff60 r4:c0c0c3c0 fbcon_prepare_logo from fbcon_init+0x408/0x4f8 r10:00000028 r9:c0a00df8 r8:00000028 r7:00000050 r6:c0e61920 r5:c0e32b00 r4:c0c0c3c0 fbcon_init from visual_init+0x9c/0xe0 r10:c0a03080 r9:00000000 r8:0000003e r7:c0a02f84 r6:00000000 r5:c0c0c624 r4:c0c0c3c0 visual_init from do_bind_con_driver+0x19c/0x370 r7:c0a02f84 r6:00000001 r5:c06affbc r4:c0c0c3c0 do_bind_con_driver from do_take_over_console+0x124/0x1b8 r10:c0a02f8c r9:00000001 r8:0000003e r7:00000000 r6:00000001 r5:00000000 r4:c06affbc do_take_over_console from do_fbcon_takeover+0x6c/0xcc r10:fffff000 r9:c0e32da4 r8:c07dbabc r7:00000000 r6:c0805a24 r5:c0a00cc8 r4:c0805a24 do_fbcon_takeover from fbcon_fb_registered+0xe4/0x128 r5:00000000 r4:c0a00dac fbcon_fb_registered from register_framebuffer+0x208/0x318 r7:c0e32b10 r6:c0a00ca8 r5:00000000 r4:c0e32b00 register_framebuffer from sa1100fb_probe+0x334/0x420 r9:00000000 r8:0000000d r7:00000004 r6:c07dfe08 r5:00000000 r4:c0e32b00 sa1100fb_probe from platform_probe+0x4c/0xac r10:c07cb85c r9:c07cb87c r8:00000000 r7:00000000 r6:c0805abc r5:c07dfe18 r4:00000000 platform_probe from really_probe+0xc0/0x280 r7:00000000 r6:c0805abc r5:c07dfe18 r4:00000000 really_probe from __driver_probe_device+0x84/0xe4 r7:00000000 r6:c07dfe18 r5:c0805abc r4:c07dfe18 __driver_probe_device from driver_probe_device+0x4c/0x10c r5:60000153 r4:c0a04c6c driver_probe_device from __driver_attach+0x90/0x104 r7:c080af60 r6:c045a7d0 r5:c0805abc r4:c07dfe18 __driver_attach from bus_for_each_dev+0x80/0xcc r7:c080af60 r6:c045a7d0 r5:c0805abc r4:00000000 bus_for_each_dev from driver_attach+0x20/0x28 r6:00000000 r5:c0e5d340 r4:c0805abc driver_attach from bus_add_driver+0x140/0x1c8 bus_add_driver from driver_register+0x7c/0x110 r7:c07a4bc8 r6:c07bc340 r5:c0c19000 r4:c0805abc driver_register from __platform_driver_register+0x20/0x28 r5:c0c19000 r4:c0818000 __platform_driver_register from sa1100fb_init+0x28/0x3c sa1100fb_init from do_one_initcall+0x78/0x220 do_one_initcall from kernel_init_freeable+0x180/0x1fc r10:c07cb85c r9:c07cb87c r8:c0818000 r7:c07a4bc8 r6:00000007 r5:c0c427a0 r4:c07d2060 kernel_init_freeable from kernel_init+0x18/0x10c r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:c0675804 r4:00000000 kernel_init from ret_from_fork+0x14/0x2c Exception stack(0xe0809fb0 to 0xe0809ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 r5:c0675804 r4:00000000 Code: e24ba02c e0026323 e08a6106 e5166044 (e58c6000) ---[ end trace 00000000c08187d8 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Reboot failed -- System halted --- # bad: [dd315b5800612e6913343524aa9b993f9a8bb0cf] Add linux-next specific files for 20220324 # good: [f443e374ae131c168a065ea1748feac6b2e76613] Linux 5.17 git bisect start 'HEAD' 'v5.17' # good: [6788381e2f3c20c25cf7ab91df9cf0d6bec153f9] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git git bisect good 6788381e2f3c20c25cf7ab91df9cf0d6bec153f9 # bad: [59c7e0caa3e7bc21dd1b6c681c87d2b307f399ee] Merge branch 'drm-next' of git://git.freedesktop.org/git/drm/drm.git git bisect bad 59c7e0caa3e7bc21dd1b6c681c87d2b307f399ee # good: [4d17d43de9d186150b3289ce99d7a79fcff202f9] net: usb: asix: suspend embedded PHY if external is used git bisect good 4d17d43de9d186150b3289ce99d7a79fcff202f9 # good: [6c64ae228f0826859c56711ce133aff037d6205f] Backmerge tag 'v5.17-rc6' into drm-next git bisect good 6c64ae228f0826859c56711ce133aff037d6205f # good: [01fd8d2522c49a333b0ee46ba19a6fedfc1c9a60] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git git bisect good 01fd8d2522c49a333b0ee46ba19a6fedfc1c9a60 # bad: [6de7e4f02640fba2ffa6ac04e2be13785d614175] Merge tag 'drm-msm-next-2022-03-01' of https://gitlab.freedesktop.org/drm/msm into drm-next git bisect bad 6de7e4f02640fba2ffa6ac04e2be13785d614175 # bad: [c9e9ce0b6f85ac330adee912745048a0af5f315d] Merge tag 'drm-misc-next-2022-03-03' of git://anongit.freedesktop.org/drm/drm-misc into drm-next git bisect bad c9e9ce0b6f85ac330adee912745048a0af5f315d # good: [e2573d5f2a5cebe789bbf415e484b589d8eebad7] drm/amd/display: limit unbounded requesting to 5k git bisect good e2573d5f2a5cebe789bbf415e484b589d8eebad7 # good: [3c54c95bd917d43d12fe1b192df9aa4c5973449b] fbdev: Remove trailing whitespaces from cfbimgblt.c git bisect good 3c54c95bd917d43d12fe1b192df9aa4c5973449b # good: [ed6e76676b2657b71a0b9e5e847d96e4de0b394b] drm: rcar-du: lvds: Add r8a77961 support git bisect good ed6e76676b2657b71a0b9e5e847d96e4de0b394b # good: [66a8af1f6e3c10190dff14a5668661c092a2a85f] Merge tag 'drm/tegra/for-5.18-rc1' of https://gitlab.freedesktop.org/drm/tegra into drm-next git bisect good 66a8af1f6e3c10190dff14a5668661c092a2a85f # bad: [701920ca9822eb63b420b3bcb627f2c1ec759903] drm/ssd130x: remove redundant initialization of pointer mode git bisect bad 701920ca9822eb63b420b3bcb627f2c1ec759903 # bad: [9ae2ac4d31a85ce59cc560d514a31b95f4ace154] drm: Add TODO item for optimizing format helpers git bisect bad 9ae2ac4d31a85ce59cc560d514a31b95f4ace154 # bad: [0d03011894d23241db1a1cad5c12aede60897d5e] fbdev: Improve performance of cfb_imageblit() git bisect bad 0d03011894d23241db1a1cad5c12aede60897d5e # first bad commit: [0d03011894d23241db1a1cad5c12aede60897d5e] fbdev: Improve performance of cfb_imageblit()
