From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Jim Kukunas Date: Fri, 27 May 2016 09:26:51 -0400 Subject: [PATCH] raid6: add Kconfig option to skip raid6 benchmarking Adds CONFIG_RAID6_FORCE_ALGO, which causes the kernel to not benchmark each raid recovery and syndrome generation algorithm, and instead use the version selected via Kconfig (CONFIG_RAID6_FORCE_{INT,SSSE3,AVX2}). In the case, the selected algorithm is not supported by the processor at runtime, a fallback is used. Signed-off-by: Jim Kukunas --- lib/Kconfig | 3 +-- lib/raid6/Kconfig | 38 +++++++++++++++++++++++++++++++ lib/raid6/algos.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 97 insertions(+), 2 deletions(-) create mode 100644 lib/raid6/Kconfig diff --git a/lib/Kconfig b/lib/Kconfig index 3321d04dfa5a..e4343fa05964 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -8,8 +8,7 @@ config BINARY_PRINTF menu "Library routines" -config RAID6_PQ - tristate +source "lib/raid6/Kconfig" config RAID6_PQ_BENCHMARK bool "Automatically choose fastest RAID6 PQ functions" diff --git a/lib/raid6/Kconfig b/lib/raid6/Kconfig new file mode 100644 index 000000000000..d881d6be89bb --- /dev/null +++ b/lib/raid6/Kconfig @@ -0,0 +1,38 @@ +menu "RAID 6" + +config RAID6_PQ + tristate + +config RAID6_FORCE_ALGO + bool "Always use specified recovery algorithm" + default n + depends on RAID6_PQ + help + If this option is not set, on every boot the kernel will + benchmark each optimized version of the RAID6 recovery and + syndrome generation algorithms and will select the one that + performs best. Microbenchmarking each version negatively + affects boot time. + + Enabling this option skips the benchmark at boot, and + instead always uses the algorithm selected. The only exception + is if the selected algorithm relies on a cpu feature not + supported at runtime. In this case, one of the lower performance + fallbacks are used. + +choice + prompt "RAID6 Recovery Algorithm" + default RAID6_FORCE_INT + depends on RAID6_FORCE_ALGO + ---help--- + Select the RAID6 recovery algorithm to unconditionally use + + config RAID6_FORCE_INT + bool "Reference Implementation" + config RAID6_FORCE_SSSE3 + bool "SSSE3" + config RAID6_FORCE_AVX2 + bool "AVX2" +endchoice + +endmenu diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c index 17417eee0866..8af3d7c737c1 100644 --- a/lib/raid6/algos.c +++ b/lib/raid6/algos.c @@ -124,6 +124,63 @@ const struct raid6_recov_calls *const raid6_recov_algos[] = { #define time_before(x, y) ((x) < (y)) #endif +#ifdef CONFIG_RAID6_FORCE_ALGO +/* TODO don't compile in algos that will never be used */ +int __init raid6_select_algo(void) +{ + const struct raid6_recov_calls *recov_fallback = &raid6_recov_intx1; + const struct raid6_recov_calls *recov_algo; + const struct raid6_calls *gen_fallback; + const struct raid6_calls *gen_algo; + +#if defined(__i386__) + gen_fallback = &raid6_intx32; +#elif defined(__x86_64__) + gen_fallback = &raid6_sse2x2; +#else +# error "TODO" +#endif + +#if defined(CONFIG_RAID6_FORCE_INT) + recov_algo = &raid6_recov_intx1; + gen_algo = &raid6_intx32; + +#elif defined(CONFIG_RAID6_FORCE_SSSE3) + recov_algo = &raid6_recov_ssse3; +#if defined(__i386__) + gen_algo = &raid6_sse2x2; +#else + gen_algo = &raid6_sse2x4; +#endif + +#elif defined(CONFIG_RAID6_FORCE_AVX2) + recov_algo = &raid6_recov_avx2; + +#if defined(__i386__) + gen_algo = &raid6_avx2x2; +#else + gen_algo = &raid6_avx2x4; +#endif + +#else +#error "RAID6 Forced Recov Algo: Unsupported selection" +#endif + + if (recov_algo->valid != NULL && recov_algo->valid() == 0) + recov_algo = recov_fallback; + + pr_info("raid6: Forced to use recovery algorithm %s\n", recov_algo->name); + + raid6_2data_recov = recov_algo->data2; + raid6_datap_recov = recov_algo->datap; + + pr_info("raid6: Forced gen() algo %s\n", gen_algo->name); + + raid6_call = *gen_algo; + + return gen_algo && recov_algo ? 0 : -EINVAL; +} +#else static inline const struct raid6_recov_calls *raid6_choose_recov(void) { const struct raid6_recov_calls *const *algo; @@ -260,6 +317,7 @@ int __init raid6_select_algo(void) return gen_best && rec_best ? 0 : -EINVAL; } +#endif static void raid6_exit(void) { -- https://clearlinux.org