Hi Michael, On Tue, Jun 05, 2018 at 12:16:22PM +1000, Michael Ellerman wrote: > Hi Simon, > > wei.guo.si...@gmail.com writes: > > From: Simon Guo <wei.guo.si...@gmail.com> > > > > There is some room to optimize memcmp() in powerpc 64 bits version for > > following 2 cases: > > (1) Even src/dst addresses are not aligned with 8 bytes at the beginning, > > memcmp() can align them and go with .Llong comparision mode without > > fallback to .Lshort comparision mode do compare buffer byte by byte. > > (2) VMX instructions can be used to speed up for large size comparision, > > currently the threshold is set for 4K bytes. Notes the VMX instructions > > will lead to VMX regs save/load penalty. This patch set includes a > > patch to add a 32 bytes pre-checking to minimize the penalty. > > > > It did the similar with glibc commit dec4a7105e (powerpc: Improve memcmp > > performance for POWER8). Thanks Cyril Bur's information. > > This patch set also updates memcmp selftest case to make it compiled and > > incorporate large size comparison case. > > I'm seeing a few crashes with this applied, I haven't had time to look > into what is happening yet, sorry. Sorry I didn't catch this in my testing. I will check the root cause and update later.
Thanks, - Simon > > [ 2471.300595] kselftest: Running tests in user > [ 2471.302785] calling test_user_copy_init+0x0/0xd14 [test_user_copy] @ 44883 > [ 2471.302892] Unable to handle kernel paging request for data at address > 0xc008000018553005 > [ 2471.303014] Faulting instruction address: 0xc00000000001f29c > [ 2471.303119] Oops: Kernel access of bad area, sig: 11 [#1] > [ 2471.303193] LE SMP NR_CPUS=2048 NUMA PowerNV > [ 2471.303256] Modules linked in: test_user_copy(+) vxlan ip6_udp_tunnel > udp_tunnel 8021q bridge stp llc dummy test_printf test_firmware vmx_crypto > crct10dif_vpmsum crct10dif_common crc32c_vpmsum veth [last unloaded: > test_static_key_base] > [ 2471.303532] CPU: 4 PID: 44883 Comm: modprobe Tainted: G W > 4.17.0-rc3-gcc7x-g7204012 #1 > [ 2471.303644] NIP: c00000000001f29c LR: c00000000001f6e4 CTR: > 0000000000000000 > [ 2471.303754] REGS: c000001fddc2b560 TRAP: 0300 Tainted: G W > (4.17.0-rc3-gcc7x-g7204012) > [ 2471.303873] MSR: 9000000002009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE> CR: > 24222844 XER: 00000000 > [ 2471.303996] CFAR: c00000000001f6e0 DAR: c008000018553005 DSISR: 40000000 > IRQMASK: 0 > [ 2471.303996] GPR00: c00000000001f6e4 c000001fddc2b7e0 c008000018529900 > 0000000002000000 > [ 2471.303996] GPR04: c000001fe4b90020 000000000000ffe0 0000000000000000 > 03fffffe01b48000 > [ 2471.303996] GPR08: 0000000080000000 c008000018553005 c000001fddc28000 > c008000018520df0 > [ 2471.303996] GPR12: c00000000009c430 c000001fffffbc00 0000000020000000 > 0000000000000000 > [ 2471.303996] GPR16: c000001fddc2bc20 0000000000000030 c0000000001f7ba0 > 0000000000000001 > [ 2471.303996] GPR20: 0000000000000000 c000000000c772b0 c0000000010b4018 > 0000000000000000 > [ 2471.303996] GPR24: 0000000000000000 c008000018521c98 0000000000000000 > c000001fe4b90000 > [ 2471.303996] GPR28: fffffffffffffff4 0000000002000000 9000000002009033 > 9000000002009033 > [ 2471.304930] NIP [c00000000001f29c] msr_check_and_set+0x3c/0xc0 > [ 2471.305008] LR [c00000000001f6e4] enable_kernel_altivec+0x44/0x100 > [ 2471.305084] Call Trace: > [ 2471.305122] [c000001fddc2b7e0] [c00000000009baa8] > __copy_tofrom_user_base+0x9c/0x574 (unreliable) > [ 2471.305240] [c000001fddc2b860] [c00000000001f6e4] > enable_kernel_altivec+0x44/0x100 > [ 2471.305336] [c000001fddc2b890] [c00000000009ce40] enter_vmx_ops+0x50/0x70 > [ 2471.305418] [c000001fddc2b8b0] [c00000000009c768] memcmp+0x338/0x680 > [ 2471.305501] [c000001fddc2b9b0] [c008000018520190] > test_user_copy_init+0x188/0xd14 [test_user_copy] > [ 2471.305617] [c000001fddc2ba60] [c00000000000de20] > do_one_initcall+0x90/0x560 > [ 2471.305710] [c000001fddc2bb30] [c000000000200630] do_init_module+0x90/0x260 > [ 2471.305795] [c000001fddc2bbc0] [c0000000001fec88] load_module+0x1a28/0x1ce0 > [ 2471.305875] [c000001fddc2bd70] [c0000000001ff1e8] > sys_finit_module+0xc8/0x110 > [ 2471.305983] [c000001fddc2be30] [c00000000000b528] system_call+0x58/0x6c > [ 2471.306066] Instruction dump: > [ 2471.306112] fba1ffe8 fbc1fff0 fbe1fff8 f8010010 f821ff81 7c7d1b78 60000000 > 60000000 > [ 2471.306216] 7fe000a6 3d220003 39299705 7ffeeb78 <89290000> 2f890000 > 419e0044 60000000 > [ 2471.306326] ---[ end trace daf8d409e65b9841 ]--- > > And: > > [ 19.096709] test_bpf: test_skb_segment: success in skb_segment! > [ 19.096799] initcall test_bpf_init+0x0/0xae0 [test_bpf] returned 0 after > 591217 usecs > [ 19.115869] calling test_user_copy_init+0x0/0xd14 [test_user_copy] @ 3159 > [ 19.116165] Unable to handle kernel paging request for data at address > 0xd000000003852805 > [ 19.116352] Faulting instruction address: 0xc00000000001f44c > [ 19.116483] Oops: Kernel access of bad area, sig: 11 [#1] > [ 19.116583] LE SMP NR_CPUS=2048 NUMA pSeries > [ 19.116684] Modules linked in: test_user_copy(+) lzo_compress crc_itu_t > zstd_compress zstd_decompress test_bpf test_static_keys test_static_key_base > xxhash test_firmware af_key cls_bpf act_bpf bridge nf_nat_irc xt_NFLOG > nfnetlink_log xt_policy nf_conntrack_netlink nfnetlink xt_nat > nf_conntrack_irc xt_mark xt_tcpudp nf_nat_sip xt_TCPMSS xt_LOG nf_nat_ftp > nf_conntrack_ftp xt_conntrack nf_conntrack_sip xt_addrtype xt_state 8021q > iptable_filter ipt_MASQUERADE nf_log_ipv4 iptable_mangle > nf_nat_masquerade_ipv4 ipt_REJECT nf_reject_ipv4 iptable_nat > nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack ip_tables > x_tables nf_log_arp nf_log_common ah4 ipcomp xfrm4_tunnel esp4 rpcrdma stp > p8022 psnap llc xfrm_ipcomp xfrm_user xfrm_algo platform_lcd lcd ocxl > virtio_balloon virtio_crypto crypto_engine > [ 19.118040] vmx_crypto nbd zram zsmalloc virtio_blk st be2iscsi cxgb3i > cxgb4i libcxgbi bnx2i ibmvfc sym53c8xx scsi_transport_spi scsi_dh_alua > scsi_dh_rdac qla4xxx mpt3sas scsi_transport_sas cxlflash cxl libiscsi_tcp > lpfc crc_t10dif crct10dif_generic crct10dif_common qla2xxx iscsi_boot_sysfs > raid_class parport_pc parport powernv_op_panel powernv_rng pseries_rng > rng_core virtio_console pcspkr input_leds evdev dm_round_robin dm_mirror > dm_region_hash dm_log raid10 dm_service_time multipath dm_queue_length > dm_multipath dm_thin_pool faulty dm_persistent_data dm_zero dm_crypt > dm_bio_prison dm_snapshot dm_bufio raid456 async_raid6_recov async_memcpy > async_pq async_xor async_tx xor raid6_pq rpadlpar_io rpaphp jsm icom hvcs > ib_ipoib ib_srp ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_ucm ib_ucm > ib_uverbs > [ 19.119505] rdma_cm iw_cm ib_cm mlx4_ib iw_cxgb3 iw_cxgb4 ib_mthca > ib_core leds_powernv led_class vhost_net vhost macvtap macvlan dummy bsd_comp > ppp_async crc_ccitt pppoe ppp_synctty pppox ppp_deflate ppp_generic 3c59x > s2io bnx2 cnic uio bnx2x libcrc32c i40e ixgbe ixgb cxgb3 libcxgb cxgb cxgb4 > pcnet32 netxen_nic qlge be2net acenic mlx4_en mlx4_core myri10ge bonding slhc > tap mdio veth vxlan udp_tunnel tun usb_storage usbmon oprofile sha1_powerpc > md5_ppc crc32c_vpmsum kvm hvcserver > [ 19.120358] CPU: 4 PID: 3159 Comm: modprobe Not tainted > 4.17.0-rc3-gcc7x-g7204012 #1 > [ 19.120508] NIP: c00000000001f44c LR: c00000000001f894 CTR: > 0000000000000000 > [ 19.120666] REGS: c0000000f8d9f570 TRAP: 0300 Not tainted > (4.17.0-rc3-gcc7x-g7204012) > [ 19.120817] MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 24222844 > XER: 00000000 > [ 19.120984] CFAR: c00000000000c03c DAR: d000000003852805 DSISR: 40000000 > IRQMASK: 0 > GPR00: c00000000001f894 c0000000f8d9f7f0 d000000003829900 > 0000000002000000 > GPR04: c0000000f9a30048 000000000000ffe0 0000000000000000 > 03fffffff065dffd > GPR08: 0000000080000000 d000000003852805 c0000000f8d9c000 > d000000003820df0 > GPR12: c00000000009ebb0 c00000003fffb300 c0000000f8d9fd90 > d000000003840000 > GPR16: d000000003840000 0000000000000000 c0000000011d6900 > d000000003821ad0 > GPR20: c000000000bd7860 0000000000000000 c000000000ff9060 > 00000000014000c0 > GPR24: 0000000000000000 0000000000000000 0000000000000100 > c0000000f9a30028 > GPR28: fffffffffffffff4 0000000002000000 8000000002009033 > 8000000000009033 > [ 19.122454] NIP [c00000000001f44c] msr_check_and_set+0x3c/0xc0 > [ 19.122580] LR [c00000000001f894] enable_kernel_altivec+0x44/0x100 > [ 19.122707] Call Trace: > [ 19.122789] [c0000000f8d9f7f0] [c00000000009e228] > __copy_tofrom_user_base+0x9c/0x574 (unreliable) > [ 19.122962] [c0000000f8d9f870] [c00000000001f894] > enable_kernel_altivec+0x44/0x100 > [ 19.123344] [c0000000f8d9f8a0] [c00000000009f740] enter_vmx_ops+0x50/0x70 > [ 19.123583] [c0000000f8d9f8c0] [c00000000009eee8] memcmp+0x338/0x680 > [ 19.123728] [c0000000f8d9f9c0] [d000000003820190] > test_user_copy_init+0x188/0xd14 [test_user_copy] > [ 19.123909] [c0000000f8d9fa70] [c00000000000e37c] > do_one_initcall+0x5c/0x2d0 > [ 19.124094] [c0000000f8d9fb30] [c00000000020066c] do_init_module+0x90/0x264 > [ 19.124234] [c0000000f8d9fbc0] [c0000000001ff084] load_module+0x2f64/0x3600 > [ 19.124371] [c0000000f8d9fd70] [c0000000001ff9c8] > sys_finit_module+0xc8/0x110 > [ 19.124530] [c0000000f8d9fe30] [c00000000000b868] system_call+0x58/0x6c > [ 19.124648] Instruction dump: > [ 19.124721] fba1ffe8 fbc1fff0 fbe1fff8 f8010010 f821ff81 7c7d1b78 60000000 > 60000000 > [ 19.124869] 7fe000a6 3d220003 39298f05 7ffeeb78 <89290000> 2f890000 > 419e0044 60000000 > [ 19.125034] ---[ end trace 7c08acedd4b4e6aa ]--- > > > cheers
