| Message ID | 20221012215931.3896-1-elliott@hpe.com |
|---|---|
| Headers | show |
| Series | crypto: x86 - fix RCU stalls | expand |
> -----Original Message----- > From: Elliott, Robert (Servers) <elliott@hpe.com> > Sent: Wednesday, October 12, 2022 4:59 PM > To: herbert@gondor.apana.org.au; davem@davemloft.net; > tim.c.chen@linux.intel.com; ap420073@gmail.com; ardb@kernel.org; linux- > crypto@vger.kernel.org; linux-kernel@vger.kernel.org > Cc: Elliott, Robert (Servers) <elliott@hpe.com> > Subject: [PATCH v2 00/19] crypto: x86 - fix RCU stalls > > This series fixes the RCU stalls triggered by the x86 crypto > modules discussed in > https://lore.kernel.org/all/MW5PR84MB18426EBBA3303770A8BC0BDFAB759@MW5PR84 > MB1842.NAMPRD84.PROD.OUTLOOK.COM/ I've instrumented all the x86 crypto modules, including ways to experiment with different loop sizes. Here are some results with the hash functions. Key: calls = number of kernel_fpu_begin()/end() calls made by the module cost = number of CPU cycles consumed by those calls (overhead) maxcycles = number of CPU cycles between those calls in FPU context bpf = bytes_per_fpu loop size KiB = bpf expressed in KiB maxlen = maximum number of bytes per loop via update() maxlen2 = maximum number of bytes per loop via finup() This is on a 2.2 GHz Cascade Lake CPU, where each cycle is nominally 0.45 ns. The CPU does not support SHA-NI instructions, so those results are missing. Here are the results from a boot with the avx2 bytes_per_fpu values set to 0 (unlimited - original behavior). Booting includes: - processing 2.3 GB of SHA-512 kernel module hashes - crypto self-tests - crypto extra self-tests (CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y) calls cost maxcycles bpf KiB maxlen maxlen2 algorithm module ======== =========== ============ ======== ==== ======== ======== ======================== ============================ 3641 177182 10230 0 0 4096 0 __ghash-pclmulqdqni ghash_clmulni_intel 2242 150516 1684 0 0 8112 0 crc32-pclmul crc32_pclmul 1008 43800 22404 0 0 8068 8105 crc32c-intel crc32c_intel 2565 179734 4286 0 0 7791 8027 crct10dif-pclmul crct10dif_pclmul 1603 77112 2414 0 0 8132 0 nhpoly1305-avx2 nhpoly1305_avx2 1671 81108 9390 203776 199 8109 0 nhpoly1305-sse2 nhpoly1305_sse2 1977 103598 5314 0 0 8112 0 poly1305-simd poly1305_x86_64 26744 1251756 2046 0 0 8096 0 polyval-clmulni polyval_clmulni 14669 682428 65462 30720 30 251 8096 sha1-avx sha1_ssse3 14669 682428 65462 0 0 7170 0 sha1-avx2 sha1_ssse3 14669 682428 65462 34816 34 0 0 sha1-shani sha1_ssse3 14669 682428 65462 26624 26 8089 8164 sha1-ssse3 sha1_ssse3 26768 1230100 144902 11264 11 8130 8159 sha224-avx sha256_ssse3 26768 1230100 144902 13312 13 8078 8146 sha224-avx2 sha256_ssse3 26768 1230100 144902 13312 13 0 0 sha224-shani sha256_ssse3 26768 1230100 144902 11264 11 8068 8168 sha224-ssse3 sha256_ssse3 26768 1230100 144902 11264 11 8130 8159 sha256-avx sha256_ssse3 26768 1230100 144902 13312 13 8078 8146 sha256-avx2 sha256_ssse3 26768 1230100 144902 13312 13 0 0 sha256-shani sha256_ssse3 26768 1230100 144902 11264 11 8068 8168 sha256-ssse3 sha256_ssse3 29157 2044882 164510724 17408 17 0 8127 sha384-avx sha512_ssse3 29157 2044882 164510724 0 0 0 48175432 sha384-avx2 sha512_ssse3 29157 2044882 164510724 17408 17 0 8055 sha384-ssse3 sha512_ssse3 29157 2044882 164510724 17408 17 0 8127 sha512-avx sha512_ssse3 29157 2044882 164510724 0 0 0 48175432 sha512-avx2 sha512_ssse3 29157 2044882 164510724 17408 17 0 8055 sha512-ssse3 sha512_ssse3 4314 193456 124918 0 0 7672 8101 sm3-avx sm3_avx_x86_64 The self-tests only test small data sets (even the extra tests limit themselves to PAGE_SIZE * 2) so only the sha512_ssse3 module was stressed with large requests. The cost of the kernel_fpu_begin()/end() calls (2044882 cycles) was 929 us, and the longest time in FPU context (164510724) was 75 ms. I think the biggest file it encounters is: -rw-r--r--. 1 root root 48186713 Nov 1 13:14 /lib/modules/6.0.0+/kernel/fs/xfs/xfs.ko I added tcrypt tests to exercise each driver ten times with 1 MiB data, and that exposes all the drivers to larger requests. bigbuf tests with no limits: calls cost maxcycles bpf KiB maxlen maxlen2 algorithm module ======== =========== ============ ======== ==== ======== ======== ======================== ============================ 1000 156354 1484434 0 0 1048576 0 __ghash-pclmulqdqni ghash_clmulni_intel 1000 150386 221710 0 0 1048576 0 crc32-pclmul crc32_pclmul 1000 104890 114000 0 0 1048576 0 crc32c-intel crc32c_intel 1000 169596 182904 0 0 1048576 0 crct10dif-pclmul crct10dif_pclmul 1000 122842 267568 0 0 1048576 0 nhpoly1305-avx2 nhpoly1305_avx2 1000 190530 453118 0 0 1048576 0 nhpoly1305-sse2 nhpoly1305_sse2 1000 134682 431264 0 0 1048576 0 poly1305-simd poly1305_x86_64 8000 387206 215922 0 0 1048576 0 polyval-clmulni polyval_clmulni 6000 562932 2831190 0 0 1048576 0 sha1-avx sha1_ssse3 6000 562932 2831190 0 0 1048576 0 sha1-avx2 sha1_ssse3 6000 562932 2831190 34816 34 0 0 sha1-shani sha1_ssse3 6000 562932 2831190 0 0 1048576 0 sha1-ssse3 sha1_ssse3 12000 1212742 6558712 0 0 1048576 0 sha224-avx sha256_ssse3 12000 1212742 6558712 0 0 1048576 0 sha224-avx2 sha256_ssse3 12000 1212742 6558712 13312 13 0 0 sha224-shani sha256_ssse3 12000 1212742 6558712 0 0 1048576 0 sha224-ssse3 sha256_ssse3 12000 1212742 6558712 0 0 1048576 0 sha256-avx sha256_ssse3 12000 1212742 6558712 0 0 1048576 0 sha256-avx2 sha256_ssse3 12000 1212742 6558712 13312 13 0 0 sha256-shani sha256_ssse3 12000 1212742 6558712 0 0 1048576 0 sha256-ssse3 sha256_ssse3 12006 1250296 4621038 0 0 1048576 0 sha384-avx sha512_ssse3 12006 1250296 4621038 0 0 1048576 1037416 sha384-avx2 sha512_ssse3 12006 1250296 4621038 0 0 1048576 0 sha384-ssse3 sha512_ssse3 12006 1250296 4621038 0 0 1048576 0 sha512-avx sha512_ssse3 12006 1250296 4621038 0 0 1048576 1037416 sha512-avx2 sha512_ssse3 12006 1250296 4621038 0 0 1048576 0 sha512-ssse3 sha512_ssse3 2000 221468 6236756 0 0 1048576 0 sm3-avx sm3_avx_x86_64 Setting bpf limits based on those results narrows the maxcycles in FPU context. I've seen results vary from 81912 (37 us) to (102 us) - not real tight, but much better than ranging up to 75 ms. bigbuf tests with bytes_per_fpu limits as shown: calls cost maxcycles bpf KiB maxlen maxlen2 algorithm module ======== =========== ============ ======== ==== ======== ======== ======================== ============================ 21000 1002372 138558 51200 50 51200 0 __ghash-pclmulqdqni ghash_clmulni_intel 2000 220666 226806 646912 631 646912 0 crc32-pclmul crc32_pclmul 2000 255110 105968 895232 874 895232 0 crc32c-intel crc32c_intel 2000 218942 107930 626944 612 626944 0 crct10dif-pclmul crct10dif_pclmul 4000 208170 141356 345088 337 345088 0 nhpoly1305-avx2 nhpoly1305_avx2 6000 285286 105072 203520 198 203520 0 nhpoly1305-sse2 nhpoly1305_sse2 5000 368866 162262 222976 217 222976 0 poly1305-simd poly1305_x86_64 10000 457010 142362 402688 393 402688 0 polyval-clmulni polyval_clmulni 108000 6048076 160670 30720 30 30720 0 sha1-avx sha1_ssse3 108000 6048076 160670 34816 34 34816 0 sha1-avx2 sha1_ssse3 108000 6048076 160670 27392 26 27392 0 sha1-ssse3 sha1_ssse3 520000 23646576 196462 11520 11 11520 0 sha224-avx sha256_ssse3 520000 23646576 196462 14080 13 14080 0 sha224-avx2 sha256_ssse3 520000 23646576 196462 11776 11 11776 0 sha224-ssse3 sha256_ssse3 520000 23646576 196462 11520 11 11520 0 sha256-avx sha256_ssse3 520000 23646576 196462 14080 13 14080 0 sha256-avx2 sha256_ssse3 520000 23646576 196462 11776 11 11776 0 sha256-ssse3 sha256_ssse3 356156 18242860 226538 17152 16 17152 0 sha384-avx sha512_ssse3 356156 18242860 226538 20480 20 20480 20480 sha384-avx2 sha512_ssse3 356156 18242860 226538 17408 17 17408 0 sha384-ssse3 sha512_ssse3 356156 18242860 226538 17152 16 17152 0 sha512-avx sha512_ssse3 356156 18242860 226538 20480 20 20480 20480 sha512-avx2 sha512_ssse3 356156 18242860 226538 17408 17 17408 0 sha512-ssse3 sha512_ssse3 93000 4537164 138924 11520 11 11520 0 sm3-avx sm3_avx_x86_64 If I reboot with sha512-avx2 set to 20 KiB, the sha512-avx2 maxlength can still take a long time (e.g., 2 ms). That's much better than the original 75 ms, but still not in the 50 us range. I set /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor to "performance" in .bash_profile, but that's not effective during boot, so maybe that is the source of variability. Example boot with 20 KiB limit: calls cost maxcycles bpf KiB maxlen maxlen2 algorithm module ======== =========== ============ ======== ==== ======== ======== ======================== ============================ 161011 16232280 4049644 20480 20 0 20480 sha512-avx2 sha512_ssse3 Limiting it to 1 KiB does reduce maxcycles to the us range, but the cost of all the extra calls soars. So, for v3 of the series, I plan to propose values ranging from: - 11 to 20 KiB for sha* amd sm3 - 200 to 400 Kib for *poly* - 600 to 800 KiB for crc* v3 will only cover the hash functions - skcipher and aead have some unique challenges that we can tackle later.
This series fixes the RCU stalls triggered by the x86 crypto modules discussed in https://lore.kernel.org/all/MW5PR84MB18426EBBA3303770A8BC0BDFAB759@MW5PR84MB1842.NAMPRD84.PROD.OUTLOOK.COM/ Two root causes were: - too much data processed between kernel_fpu_begin and kernel_fpu_end calls (which are heavily used by the x86 optimized drivers) - tcrypt not calling cond_resched during speed test loops These problems have always been lurking, but improving the loading of the x86/sha512 module led to it happening a lot during boot when using SHA-512 for module signature checking. Fixing these problems makes it safer to improve loading the rest of the x86 modules like the sha512 module. This series only handles the x86 modules. Testing ======= The most effective testing was by enabling CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y which creates random test vectors and compares the results of the CPU-optimized function to the generic function, and running two threads of repeated modprobe commands to exercise those tests: watch -n 0 modprobe tcrypt mode=200 watch -n 0 ./tcrypt_sweep where tcrypt_sweep walks through all the test modes: #!/usr/bin/perl use strict; my @modes; open SOURCE, "<", "/home/me/linux/crypto/tcrypt.c" or die $!; while (<SOURCE>) { if (/^\s+case ([0-9]+):$/) { push @modes, $1; } } close SOURCE; foreach (@modes) { print "$_ "; # don't run mode 300, which runs 301-399 # don't run mode 400, which runs 401-499 if (($_ eq "0") || ($_ eq "300") || ($_ eq "400")) { system "echo \"===== Skipping special modprobe tcrypt mode=$_\" > /dev/kmsg"; } else { system "echo \"Running modprobe tcrypt mode=$_\" > /dev/kmsg"; system "modprobe tcrypt mode=$_"; } } Robert Elliott (19): crypto: tcrypt - test crc32 crypto: tcrypt - test nhpoly1305 crypto: tcrypt - reschedule during cycles speed tests crypto: x86/sha - limit FPU preemption crypto: x86/crc - limit FPU preemption crypto: x86/sm3 - limit FPU preemption crypto: x86/ghash - restructure FPU context saving crypto: x86/ghash - limit FPU preemption crypto: x86 - use common macro for FPU limit crypto: x86/sha1, sha256 - load based on CPU features crypto: x86/crc - load based on CPU features crypto: x86/sm3 - load based on CPU features crypto: x86/ghash - load based on CPU features crypto: x86 - load based on CPU features crypto: x86 - add pr_fmt to all modules crypto: x86 - print CPU optimized loaded messages crypto: x86 - standardize suboptimal prints crypto: x86 - standardize not loaded prints crypto: x86/sha - register only the best function arch/x86/crypto/aegis128-aesni-glue.c | 21 ++- arch/x86/crypto/aesni-intel_glue.c | 31 ++-- arch/x86/crypto/aria_aesni_avx_glue.c | 19 +- arch/x86/crypto/blake2s-glue.c | 34 +++- arch/x86/crypto/blowfish_glue.c | 19 +- arch/x86/crypto/camellia_aesni_avx2_glue.c | 25 ++- arch/x86/crypto/camellia_aesni_avx_glue.c | 24 ++- arch/x86/crypto/camellia_glue.c | 20 ++- arch/x86/crypto/cast5_avx_glue.c | 21 ++- arch/x86/crypto/cast6_avx_glue.c | 21 ++- arch/x86/crypto/chacha_glue.c | 35 +++- arch/x86/crypto/crc32-pclmul_asm.S | 6 +- arch/x86/crypto/crc32-pclmul_glue.c | 37 ++-- arch/x86/crypto/crc32c-intel_glue.c | 51 ++++-- arch/x86/crypto/crct10dif-pclmul_glue.c | 54 ++++-- arch/x86/crypto/curve25519-x86_64.c | 27 ++- arch/x86/crypto/des3_ede_glue.c | 16 +- arch/x86/crypto/ghash-clmulni-intel_glue.c | 40 +++-- arch/x86/crypto/nhpoly1305-avx2-glue.c | 27 ++- arch/x86/crypto/nhpoly1305-sse2-glue.c | 23 ++- arch/x86/crypto/poly1305_glue.c | 64 +++++-- arch/x86/crypto/polyval-clmulni_glue.c | 14 +- arch/x86/crypto/serpent_avx2_glue.c | 25 ++- arch/x86/crypto/serpent_avx_glue.c | 21 ++- arch/x86/crypto/serpent_sse2_glue.c | 19 +- arch/x86/crypto/sha1_ssse3_glue.c | 188 +++++++++++-------- arch/x86/crypto/sha256_ssse3_glue.c | 198 ++++++++++++--------- arch/x86/crypto/sha512_ssse3_glue.c | 154 +++++++++------- arch/x86/crypto/sm3_avx_glue.c | 52 +++++- arch/x86/crypto/sm4_aesni_avx2_glue.c | 25 ++- arch/x86/crypto/sm4_aesni_avx_glue.c | 23 ++- arch/x86/crypto/twofish_avx_glue.c | 25 ++- arch/x86/crypto/twofish_glue.c | 19 +- arch/x86/crypto/twofish_glue_3way.c | 26 ++- crypto/tcrypt.c | 56 +++--- 35 files changed, 1060 insertions(+), 400 deletions(-)