Re: [PATCH v2 3/3] raid6: Add LoongArch SIMD recovery implementation

From: Paul Menzel
Date: Thu Aug 03 2023 - 15:50:15 EST


Dear Xuerui,


Thank you for your patches.


Am 03.08.23 um 19:08 schrieb WANG Xuerui:
From: WANG Xuerui <git@xxxxxxxxxx>

Similar to the syndrome calculation, the recovery algorithms also work
on 64 bytes at a time to align with the L1 cache line size of current
and future LoongArch cores (that we care about). Which means
unrolled-by-4 LSX and unrolled-by-2 LASX code.

The assembly is originally based on the x86 SSSE3/AVX2 ports, but
register allocation has been redone to take advantage of LSX/LASX's 32
vector registers, and instruction sequence has been optimized to suit
(e.g. LoongArch can perform per-byte srl and andi on vectors, but x86
cannot).

Performance numbers measured by instrumenting the raid6test code:

It’d be great, if you also documented your test setup. That’s always good for benchmarking numbers.

lasx 2data: 354.987 MiB/s
lasx datap: 350.430 MiB/s
lsx 2data: 340.026 MiB/s
lsx datap: 337.318 MiB/s
intx1 2data: 164.280 MiB/s
intx1 datap: 187.966 MiB/s

So the speed is more than doubled. Nice job! The lasx implementation is always the fastest. Is it therefore the preferred one? Or does it come with higher power consumption?

Signed-off-by: WANG Xuerui <git@xxxxxxxxxx>

Out of curiosity, what is your “first” name?

---
include/linux/raid/pq.h | 2 +
lib/raid6/Makefile | 2 +-
lib/raid6/algos.c | 8 +
lib/raid6/recov_loongarch_simd.c | 515 +++++++++++++++++++++++++++++++
lib/raid6/test/Makefile | 2 +-
5 files changed, 527 insertions(+), 2 deletions(-)
create mode 100644 lib/raid6/recov_loongarch_simd.c


Kind regards,

Paul


diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 8744474858487..006e18decfad0 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -125,6 +125,8 @@ extern const struct raid6_recov_calls raid6_recov_avx2;
extern const struct raid6_recov_calls raid6_recov_avx512;
extern const struct raid6_recov_calls raid6_recov_s390xc;
extern const struct raid6_recov_calls raid6_recov_neon;
+extern const struct raid6_recov_calls raid6_recov_lsx;
+extern const struct raid6_recov_calls raid6_recov_lasx;
extern const struct raid6_calls raid6_neonx1;
extern const struct raid6_calls raid6_neonx2;
diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile
index 2b9ebe1054806..035b0a4db476a 100644
--- a/lib/raid6/Makefile
+++ b/lib/raid6/Makefile
@@ -9,7 +9,7 @@ raid6_pq-$(CONFIG_ALTIVEC) += altivec1.o altivec2.o altivec4.o altivec8.o \
vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
raid6_pq-$(CONFIG_KERNEL_MODE_NEON) += neon.o neon1.o neon2.o neon4.o neon8.o recov_neon.o recov_neon_inner.o
raid6_pq-$(CONFIG_S390) += s390vx8.o recov_s390xc.o
-raid6_pq-$(CONFIG_LOONGARCH) += loongarch_simd.o
+raid6_pq-$(CONFIG_LOONGARCH) += loongarch_simd.o recov_loongarch_simd.o
hostprogs += mktables
diff --git a/lib/raid6/algos.c b/lib/raid6/algos.c
index 739c7ebcae1a2..0ec534faf019b 100644
--- a/lib/raid6/algos.c
+++ b/lib/raid6/algos.c
@@ -111,6 +111,14 @@ const struct raid6_recov_calls *const raid6_recov_algos[] = {
#endif
#if defined(CONFIG_KERNEL_MODE_NEON)
&raid6_recov_neon,
+#endif
+#ifdef CONFIG_LOONGARCH
+#ifdef CONFIG_CPU_HAS_LASX
+ &raid6_recov_lasx,
+#endif
+#ifdef CONFIG_CPU_HAS_LSX
+ &raid6_recov_lsx,
+#endif
#endif
&raid6_recov_intx1,
NULL
diff --git a/lib/raid6/recov_loongarch_simd.c b/lib/raid6/recov_loongarch_simd.c
new file mode 100644
index 0000000000000..de9d53e81bd2d
--- /dev/null
+++ b/lib/raid6/recov_loongarch_simd.c
@@ -0,0 +1,515 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * RAID6 recovery algorithms in LoongArch SIMD (LSX & LASX)
+ *
+ * Copyright (C) 2023 WANG Xuerui <git@xxxxxxxxxx>
+ *
+ * Originally based on recov_avx2.c and recov_ssse3.c:
+ *
+ * Copyright (C) 2012 Intel Corporation
+ * Author: Jim Kukunas <james.t.kukunas@xxxxxxxxxxxxxxx>
+ */
+
+#include <linux/raid/pq.h>
+#include "loongarch.h"
+
+/*
+ * Unlike with the syndrome calculation algorithms, there's no boot-time
+ * selection of recovery algorithms by benchmarking, so we have to specify
+ * the priorities and hope the future cores will all have decent vector
+ * support (i.e. no LASX slower than LSX, or even scalar code).
+ */
+
+#ifdef CONFIG_CPU_HAS_LSX
+static int raid6_has_lsx(void)
+{
+ return cpu_has_lsx;
+}
+
+static void raid6_2data_recov_lsx(int disks, size_t bytes, int faila,
+ int failb, void **ptrs)
+{
+ u8 *p, *q, *dp, *dq;
+ const u8 *pbmul; /* P multiplier table for B data */
+ const u8 *qmul; /* Q multiplier table (for both) */
+
+ p = (u8 *)ptrs[disks-2];
+ q = (u8 *)ptrs[disks-1];
+
+ /*
+ * Compute syndrome with zero for the missing data pages
+ * Use the dead data pages as temporary storage for
+ * delta p and delta q
+ */
+ dp = (u8 *)ptrs[faila];
+ ptrs[faila] = (void *)raid6_empty_zero_page;
+ ptrs[disks-2] = dp;
+ dq = (u8 *)ptrs[failb];
+ ptrs[failb] = (void *)raid6_empty_zero_page;
+ ptrs[disks-1] = dq;
+
+ raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+ /* Restore pointer table */
+ ptrs[faila] = dp;
+ ptrs[failb] = dq;
+ ptrs[disks-2] = p;
+ ptrs[disks-1] = q;
+
+ /* Now, pick the proper data tables */
+ pbmul = raid6_vgfmul[raid6_gfexi[failb-faila]];

Should spaces be put around the operator?

+ qmul = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila] ^
+ raid6_gfexp[failb]]];
+
+ kernel_fpu_begin();
+
+ /*
+ * vr20, vr21: qmul
+ * vr22, vr23: pbmul
+ */
+ asm volatile("vld $vr20, %0" : : "m" (qmul[0]));
+ asm volatile("vld $vr21, %0" : : "m" (qmul[16]));
+ asm volatile("vld $vr22, %0" : : "m" (pbmul[0]));
+ asm volatile("vld $vr23, %0" : : "m" (pbmul[16]));
+
+ while (bytes) {
+ /* vr4 - vr7: Q */
+ asm volatile("vld $vr4, %0" : : "m" (q[0]));
+ asm volatile("vld $vr5, %0" : : "m" (q[16]));
+ asm volatile("vld $vr6, %0" : : "m" (q[32]));
+ asm volatile("vld $vr7, %0" : : "m" (q[48]));
+ /* vr4 - vr7: Q + Qxy */
+ asm volatile("vld $vr8, %0" : : "m" (dq[0]));
+ asm volatile("vld $vr9, %0" : : "m" (dq[16]));
+ asm volatile("vld $vr10, %0" : : "m" (dq[32]));
+ asm volatile("vld $vr11, %0" : : "m" (dq[48]));
+ asm volatile("vxor.v $vr4, $vr4, $vr8");
+ asm volatile("vxor.v $vr5, $vr5, $vr9");
+ asm volatile("vxor.v $vr6, $vr6, $vr10");
+ asm volatile("vxor.v $vr7, $vr7, $vr11");
+ /* vr0 - vr3: P */
+ asm volatile("vld $vr0, %0" : : "m" (p[0]));
+ asm volatile("vld $vr1, %0" : : "m" (p[16]));
+ asm volatile("vld $vr2, %0" : : "m" (p[32]));
+ asm volatile("vld $vr3, %0" : : "m" (p[48]));
+ /* vr0 - vr3: P + Pxy */
+ asm volatile("vld $vr8, %0" : : "m" (dp[0]));
+ asm volatile("vld $vr9, %0" : : "m" (dp[16]));
+ asm volatile("vld $vr10, %0" : : "m" (dp[32]));
+ asm volatile("vld $vr11, %0" : : "m" (dp[48]));
+ asm volatile("vxor.v $vr0, $vr0, $vr8");
+ asm volatile("vxor.v $vr1, $vr1, $vr9");
+ asm volatile("vxor.v $vr2, $vr2, $vr10");
+ asm volatile("vxor.v $vr3, $vr3, $vr11");
+
+ /* vr8 - vr11: higher 4 bits of each byte of (Q + Qxy) */
+ asm volatile("vsrli.b $vr8, $vr4, 4");
+ asm volatile("vsrli.b $vr9, $vr5, 4");
+ asm volatile("vsrli.b $vr10, $vr6, 4");
+ asm volatile("vsrli.b $vr11, $vr7, 4");
+ /* vr4 - vr7: lower 4 bits of each byte of (Q + Qxy) */
+ asm volatile("vandi.b $vr4, $vr4, 0x0f");
+ asm volatile("vandi.b $vr5, $vr5, 0x0f");
+ asm volatile("vandi.b $vr6, $vr6, 0x0f");
+ asm volatile("vandi.b $vr7, $vr7, 0x0f");
+ /* lookup from qmul[0] */
+ asm volatile("vshuf.b $vr4, $vr20, $vr20, $vr4");
+ asm volatile("vshuf.b $vr5, $vr20, $vr20, $vr5");
+ asm volatile("vshuf.b $vr6, $vr20, $vr20, $vr6");
+ asm volatile("vshuf.b $vr7, $vr20, $vr20, $vr7");
+ /* lookup from qmul[16] */
+ asm volatile("vshuf.b $vr8, $vr21, $vr21, $vr8");
+ asm volatile("vshuf.b $vr9, $vr21, $vr21, $vr9");
+ asm volatile("vshuf.b $vr10, $vr21, $vr21, $vr10");
+ asm volatile("vshuf.b $vr11, $vr21, $vr21, $vr11");
+ /* vr16 - vr19: B(Q + Qxy) */
+ asm volatile("vxor.v $vr16, $vr8, $vr4");
+ asm volatile("vxor.v $vr17, $vr9, $vr5");
+ asm volatile("vxor.v $vr18, $vr10, $vr6");
+ asm volatile("vxor.v $vr19, $vr11, $vr7");
+
+ /* vr4 - vr7: higher 4 bits of each byte of (P + Pxy) */
+ asm volatile("vsrli.b $vr4, $vr0, 4");
+ asm volatile("vsrli.b $vr5, $vr1, 4");
+ asm volatile("vsrli.b $vr6, $vr2, 4");
+ asm volatile("vsrli.b $vr7, $vr3, 4");
+ /* vr12 - vr15: lower 4 bits of each byte of (P + Pxy) */
+ asm volatile("vandi.b $vr12, $vr0, 0x0f");
+ asm volatile("vandi.b $vr13, $vr1, 0x0f");
+ asm volatile("vandi.b $vr14, $vr2, 0x0f");
+ asm volatile("vandi.b $vr15, $vr3, 0x0f");
+ /* lookup from pbmul[0] */
+ asm volatile("vshuf.b $vr12, $vr22, $vr22, $vr12");
+ asm volatile("vshuf.b $vr13, $vr22, $vr22, $vr13");
+ asm volatile("vshuf.b $vr14, $vr22, $vr22, $vr14");
+ asm volatile("vshuf.b $vr15, $vr22, $vr22, $vr15");
+ /* lookup from pbmul[16] */
+ asm volatile("vshuf.b $vr4, $vr23, $vr23, $vr4");
+ asm volatile("vshuf.b $vr5, $vr23, $vr23, $vr5");
+ asm volatile("vshuf.b $vr6, $vr23, $vr23, $vr6");
+ asm volatile("vshuf.b $vr7, $vr23, $vr23, $vr7");
+ /* vr4 - vr7: A(P + Pxy) */
+ asm volatile("vxor.v $vr4, $vr4, $vr12");
+ asm volatile("vxor.v $vr5, $vr5, $vr13");
+ asm volatile("vxor.v $vr6, $vr6, $vr14");
+ asm volatile("vxor.v $vr7, $vr7, $vr15");
+
+ /* vr4 - vr7: A(P + Pxy) + B(Q + Qxy) = Dx */
+ asm volatile("vxor.v $vr4, $vr4, $vr16");
+ asm volatile("vxor.v $vr5, $vr5, $vr17");
+ asm volatile("vxor.v $vr6, $vr6, $vr18");
+ asm volatile("vxor.v $vr7, $vr7, $vr19");
+ asm volatile("vst $vr4, %0" : "=m" (dq[0]));
+ asm volatile("vst $vr5, %0" : "=m" (dq[16]));
+ asm volatile("vst $vr6, %0" : "=m" (dq[32]));
+ asm volatile("vst $vr7, %0" : "=m" (dq[48]));
+
+ /* vr0 - vr3: P + Pxy + Dx = Dy */
+ asm volatile("vxor.v $vr0, $vr0, $vr4");
+ asm volatile("vxor.v $vr1, $vr1, $vr5");
+ asm volatile("vxor.v $vr2, $vr2, $vr6");
+ asm volatile("vxor.v $vr3, $vr3, $vr7");
+ asm volatile("vst $vr0, %0" : "=m" (dp[0]));
+ asm volatile("vst $vr1, %0" : "=m" (dp[16]));
+ asm volatile("vst $vr2, %0" : "=m" (dp[32]));
+ asm volatile("vst $vr3, %0" : "=m" (dp[48]));
+
+ bytes -= 64;
+ p += 64;
+ q += 64;
+ dp += 64;
+ dq += 64;
+ }
+
+ kernel_fpu_end();
+}
+
+static void raid6_datap_recov_lsx(int disks, size_t bytes, int faila,
+ void **ptrs)
+{
+ u8 *p, *q, *dq;
+ const u8 *qmul; /* Q multiplier table */
+
+ p = (u8 *)ptrs[disks-2];
+ q = (u8 *)ptrs[disks-1];
+
+ /*
+ * Compute syndrome with zero for the missing data page
+ * Use the dead data page as temporary storage for delta q
+ */
+ dq = (u8 *)ptrs[faila];
+ ptrs[faila] = (void *)raid6_empty_zero_page;
+ ptrs[disks-1] = dq;
+
+ raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+ /* Restore pointer table */
+ ptrs[faila] = dq;
+ ptrs[disks-1] = q;
+
+ /* Now, pick the proper data tables */
+ qmul = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila]]];

Only one space after qmul?

+
+ kernel_fpu_begin();
+
+ /* vr22, vr23: qmul */
+ asm volatile("vld $vr22, %0" : : "m" (qmul[0]));
+ asm volatile("vld $vr23, %0" : : "m" (qmul[16]));
+
+ while (bytes) {
+ /* vr0 - vr3: P + Dx */
+ asm volatile("vld $vr0, %0" : : "m" (p[0]));
+ asm volatile("vld $vr1, %0" : : "m" (p[16]));
+ asm volatile("vld $vr2, %0" : : "m" (p[32]));
+ asm volatile("vld $vr3, %0" : : "m" (p[48]));
+ /* vr4 - vr7: Qx */
+ asm volatile("vld $vr4, %0" : : "m" (dq[0]));
+ asm volatile("vld $vr5, %0" : : "m" (dq[16]));
+ asm volatile("vld $vr6, %0" : : "m" (dq[32]));
+ asm volatile("vld $vr7, %0" : : "m" (dq[48]));
+ /* vr4 - vr7: Q + Qx */
+ asm volatile("vld $vr8, %0" : : "m" (q[0]));
+ asm volatile("vld $vr9, %0" : : "m" (q[16]));
+ asm volatile("vld $vr10, %0" : : "m" (q[32]));
+ asm volatile("vld $vr11, %0" : : "m" (q[48]));
+ asm volatile("vxor.v $vr4, $vr4, $vr8");
+ asm volatile("vxor.v $vr5, $vr5, $vr9");
+ asm volatile("vxor.v $vr6, $vr6, $vr10");
+ asm volatile("vxor.v $vr7, $vr7, $vr11");
+
+ /* vr8 - vr11: higher 4 bits of each byte of (Q + Qx) */
+ asm volatile("vsrli.b $vr8, $vr4, 4");
+ asm volatile("vsrli.b $vr9, $vr5, 4");
+ asm volatile("vsrli.b $vr10, $vr6, 4");
+ asm volatile("vsrli.b $vr11, $vr7, 4");
+ /* vr4 - vr7: lower 4 bits of each byte of (Q + Qx) */
+ asm volatile("vandi.b $vr4, $vr4, 0x0f");
+ asm volatile("vandi.b $vr5, $vr5, 0x0f");
+ asm volatile("vandi.b $vr6, $vr6, 0x0f");
+ asm volatile("vandi.b $vr7, $vr7, 0x0f");
+ /* lookup from qmul[0] */
+ asm volatile("vshuf.b $vr4, $vr22, $vr22, $vr4");
+ asm volatile("vshuf.b $vr5, $vr22, $vr22, $vr5");
+ asm volatile("vshuf.b $vr6, $vr22, $vr22, $vr6");
+ asm volatile("vshuf.b $vr7, $vr22, $vr22, $vr7");
+ /* lookup from qmul[16] */
+ asm volatile("vshuf.b $vr8, $vr23, $vr23, $vr8");
+ asm volatile("vshuf.b $vr9, $vr23, $vr23, $vr9");
+ asm volatile("vshuf.b $vr10, $vr23, $vr23, $vr10");
+ asm volatile("vshuf.b $vr11, $vr23, $vr23, $vr11");
+ /* vr4 - vr7: qmul(Q + Qx) = Dx */
+ asm volatile("vxor.v $vr4, $vr4, $vr8");
+ asm volatile("vxor.v $vr5, $vr5, $vr9");
+ asm volatile("vxor.v $vr6, $vr6, $vr10");
+ asm volatile("vxor.v $vr7, $vr7, $vr11");
+ asm volatile("vst $vr4, %0" : "=m" (dq[0]));
+ asm volatile("vst $vr5, %0" : "=m" (dq[16]));
+ asm volatile("vst $vr6, %0" : "=m" (dq[32]));
+ asm volatile("vst $vr7, %0" : "=m" (dq[48]));
+
+ /* vr0 - vr3: P + Dx + Dx = P */
+ asm volatile("vxor.v $vr0, $vr0, $vr4");
+ asm volatile("vxor.v $vr1, $vr1, $vr5");
+ asm volatile("vxor.v $vr2, $vr2, $vr6");
+ asm volatile("vxor.v $vr3, $vr3, $vr7");
+ asm volatile("vst $vr0, %0" : "=m" (p[0]));
+ asm volatile("vst $vr1, %0" : "=m" (p[16]));
+ asm volatile("vst $vr2, %0" : "=m" (p[32]));
+ asm volatile("vst $vr3, %0" : "=m" (p[48]));
+
+ bytes -= 64;
+ p += 64;
+ q += 64;
+ dq += 64;
+ }
+
+ kernel_fpu_end();
+}
+
+const struct raid6_recov_calls raid6_recov_lsx = {
+ .data2 = raid6_2data_recov_lsx,
+ .datap = raid6_datap_recov_lsx,
+ .valid = raid6_has_lsx,
+ .name = "lsx",
+ .priority = 1,
+};
+#endif /* CONFIG_CPU_HAS_LSX */
+
+#ifdef CONFIG_CPU_HAS_LASX
+static int raid6_has_lasx(void)
+{
+ return cpu_has_lasx;
+}
+
+static void raid6_2data_recov_lasx(int disks, size_t bytes, int faila,
+ int failb, void **ptrs)
+{
+ u8 *p, *q, *dp, *dq;
+ const u8 *pbmul; /* P multiplier table for B data */
+ const u8 *qmul; /* Q multiplier table (for both) */
+
+ p = (u8 *)ptrs[disks-2];
+ q = (u8 *)ptrs[disks-1];
+
+ /*
+ * Compute syndrome with zero for the missing data pages
+ * Use the dead data pages as temporary storage for
+ * delta p and delta q
+ */
+ dp = (u8 *)ptrs[faila];
+ ptrs[faila] = (void *)raid6_empty_zero_page;
+ ptrs[disks-2] = dp;
+ dq = (u8 *)ptrs[failb];
+ ptrs[failb] = (void *)raid6_empty_zero_page;
+ ptrs[disks-1] = dq;
+
+ raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+ /* Restore pointer table */
+ ptrs[faila] = dp;
+ ptrs[failb] = dq;
+ ptrs[disks-2] = p;
+ ptrs[disks-1] = q;
+
+ /* Now, pick the proper data tables */
+ pbmul = raid6_vgfmul[raid6_gfexi[failb-faila]];

Ditto.

+ qmul = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila] ^
+ raid6_gfexp[failb]]];
+
+ kernel_fpu_begin();
+
+ /*
+ * xr20, xr21: qmul
+ * xr22, xr23: pbmul
+ */
+ asm volatile("vld $vr20, %0" : : "m" (qmul[0]));
+ asm volatile("vld $vr21, %0" : : "m" (qmul[16]));
+ asm volatile("vld $vr22, %0" : : "m" (pbmul[0]));
+ asm volatile("vld $vr23, %0" : : "m" (pbmul[16]));
+ asm volatile("xvreplve0.q $xr20, $xr20");
+ asm volatile("xvreplve0.q $xr21, $xr21");
+ asm volatile("xvreplve0.q $xr22, $xr22");
+ asm volatile("xvreplve0.q $xr23, $xr23");
+
+ while (bytes) {
+ /* xr0, xr1: Q */
+ asm volatile("xvld $xr0, %0" : : "m" (q[0]));
+ asm volatile("xvld $xr1, %0" : : "m" (q[32]));
+ /* xr0, xr1: Q + Qxy */
+ asm volatile("xvld $xr4, %0" : : "m" (dq[0]));
+ asm volatile("xvld $xr5, %0" : : "m" (dq[32]));
+ asm volatile("xvxor.v $xr0, $xr0, $xr4");
+ asm volatile("xvxor.v $xr1, $xr1, $xr5");
+ /* xr2, xr3: P */
+ asm volatile("xvld $xr2, %0" : : "m" (p[0]));
+ asm volatile("xvld $xr3, %0" : : "m" (p[32]));
+ /* xr2, xr3: P + Pxy */
+ asm volatile("xvld $xr4, %0" : : "m" (dp[0]));
+ asm volatile("xvld $xr5, %0" : : "m" (dp[32]));
+ asm volatile("xvxor.v $xr2, $xr2, $xr4");
+ asm volatile("xvxor.v $xr3, $xr3, $xr5");
+
+ /* xr4, xr5: higher 4 bits of each byte of (Q + Qxy) */
+ asm volatile("xvsrli.b $xr4, $xr0, 4");
+ asm volatile("xvsrli.b $xr5, $xr1, 4");
+ /* xr0, xr1: lower 4 bits of each byte of (Q + Qxy) */
+ asm volatile("xvandi.b $xr0, $xr0, 0x0f");
+ asm volatile("xvandi.b $xr1, $xr1, 0x0f");
+ /* lookup from qmul[0] */
+ asm volatile("xvshuf.b $xr0, $xr20, $xr20, $xr0");
+ asm volatile("xvshuf.b $xr1, $xr20, $xr20, $xr1");
+ /* lookup from qmul[16] */
+ asm volatile("xvshuf.b $xr4, $xr21, $xr21, $xr4");
+ asm volatile("xvshuf.b $xr5, $xr21, $xr21, $xr5");
+ /* xr6, xr7: B(Q + Qxy) */
+ asm volatile("xvxor.v $xr6, $xr4, $xr0");
+ asm volatile("xvxor.v $xr7, $xr5, $xr1");
+
+ /* xr4, xr5: higher 4 bits of each byte of (P + Pxy) */
+ asm volatile("xvsrli.b $xr4, $xr2, 4");
+ asm volatile("xvsrli.b $xr5, $xr3, 4");
+ /* xr0, xr1: lower 4 bits of each byte of (P + Pxy) */
+ asm volatile("xvandi.b $xr0, $xr2, 0x0f");
+ asm volatile("xvandi.b $xr1, $xr3, 0x0f");
+ /* lookup from pbmul[0] */
+ asm volatile("xvshuf.b $xr0, $xr22, $xr22, $xr0");
+ asm volatile("xvshuf.b $xr1, $xr22, $xr22, $xr1");
+ /* lookup from pbmul[16] */
+ asm volatile("xvshuf.b $xr4, $xr23, $xr23, $xr4");
+ asm volatile("xvshuf.b $xr5, $xr23, $xr23, $xr5");
+ /* xr0, xr1: A(P + Pxy) */
+ asm volatile("xvxor.v $xr0, $xr0, $xr4");
+ asm volatile("xvxor.v $xr1, $xr1, $xr5");
+
+ /* xr0, xr1: A(P + Pxy) + B(Q + Qxy) = Dx */
+ asm volatile("xvxor.v $xr0, $xr0, $xr6");
+ asm volatile("xvxor.v $xr1, $xr1, $xr7");
+
+ /* xr2, xr3: P + Pxy + Dx = Dy */
+ asm volatile("xvxor.v $xr2, $xr2, $xr0");
+ asm volatile("xvxor.v $xr3, $xr3, $xr1");
+
+ asm volatile("xvst $xr0, %0" : "=m" (dq[0]));
+ asm volatile("xvst $xr1, %0" : "=m" (dq[32]));
+ asm volatile("xvst $xr2, %0" : "=m" (dp[0]));
+ asm volatile("xvst $xr3, %0" : "=m" (dp[32]));
+
+ bytes -= 64;
+ p += 64;
+ q += 64;
+ dp += 64;
+ dq += 64;
+ }
+
+ kernel_fpu_end();
+}
+
+static void raid6_datap_recov_lasx(int disks, size_t bytes, int faila,
+ void **ptrs)
+{
+ u8 *p, *q, *dq;
+ const u8 *qmul; /* Q multiplier table */
+
+ p = (u8 *)ptrs[disks-2];
+ q = (u8 *)ptrs[disks-1];
+
+ /*
+ * Compute syndrome with zero for the missing data page
+ * Use the dead data page as temporary storage for delta q
+ */
+ dq = (u8 *)ptrs[faila];
+ ptrs[faila] = (void *)raid6_empty_zero_page;
+ ptrs[disks-1] = dq;
+
+ raid6_call.gen_syndrome(disks, bytes, ptrs);
+
+ /* Restore pointer table */
+ ptrs[faila] = dq;
+ ptrs[disks-1] = q;
+
+ /* Now, pick the proper data tables */
+ qmul = raid6_vgfmul[raid6_gfinv[raid6_gfexp[faila]]];

Ditto.

+
+ kernel_fpu_begin();
+
+ /* xr22, xr23: qmul */
+ asm volatile("vld $vr22, %0" : : "m" (qmul[0]));
+ asm volatile("xvreplve0.q $xr22, $xr22");
+ asm volatile("vld $vr23, %0" : : "m" (qmul[16]));
+ asm volatile("xvreplve0.q $xr23, $xr23");
+
+ while (bytes) {
+ /* xr0, xr1: P + Dx */
+ asm volatile("xvld $xr0, %0" : : "m" (p[0]));
+ asm volatile("xvld $xr1, %0" : : "m" (p[32]));
+ /* xr2, xr3: Qx */
+ asm volatile("xvld $xr2, %0" : : "m" (dq[0]));
+ asm volatile("xvld $xr3, %0" : : "m" (dq[32]));
+ /* xr2, xr3: Q + Qx */
+ asm volatile("xvld $xr4, %0" : : "m" (q[0]));
+ asm volatile("xvld $xr5, %0" : : "m" (q[32]));
+ asm volatile("xvxor.v $xr2, $xr2, $xr4");
+ asm volatile("xvxor.v $xr3, $xr3, $xr5");
+
+ /* xr4, xr5: higher 4 bits of each byte of (Q + Qx) */
+ asm volatile("xvsrli.b $xr4, $xr2, 4");
+ asm volatile("xvsrli.b $xr5, $xr3, 4");
+ /* xr2, xr3: lower 4 bits of each byte of (Q + Qx) */
+ asm volatile("xvandi.b $xr2, $xr2, 0x0f");
+ asm volatile("xvandi.b $xr3, $xr3, 0x0f");
+ /* lookup from qmul[0] */
+ asm volatile("xvshuf.b $xr2, $xr22, $xr22, $xr2");
+ asm volatile("xvshuf.b $xr3, $xr22, $xr22, $xr3");
+ /* lookup from qmul[16] */
+ asm volatile("xvshuf.b $xr4, $xr23, $xr23, $xr4");
+ asm volatile("xvshuf.b $xr5, $xr23, $xr23, $xr5");
+ /* xr2, xr3: qmul(Q + Qx) = Dx */
+ asm volatile("xvxor.v $xr2, $xr2, $xr4");
+ asm volatile("xvxor.v $xr3, $xr3, $xr5");
+
+ /* xr0, xr1: P + Dx + Dx = P */
+ asm volatile("xvxor.v $xr0, $xr0, $xr2");
+ asm volatile("xvxor.v $xr1, $xr1, $xr3");
+
+ asm volatile("xvst $xr2, %0" : "=m" (dq[0]));
+ asm volatile("xvst $xr3, %0" : "=m" (dq[32]));
+ asm volatile("xvst $xr0, %0" : "=m" (p[0]));
+ asm volatile("xvst $xr1, %0" : "=m" (p[32]));
+
+ bytes -= 64;
+ p += 64;
+ q += 64;
+ dq += 64;
+ }
+
+ kernel_fpu_end();
+}
+
+const struct raid6_recov_calls raid6_recov_lasx = {
+ .data2 = raid6_2data_recov_lasx,
+ .datap = raid6_datap_recov_lasx,
+ .valid = raid6_has_lasx,
+ .name = "lasx",
+ .priority = 2,
+};
+#endif /* CONFIG_CPU_HAS_LASX */
diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile
index 7b244bce32b3d..2abe0076a636c 100644
--- a/lib/raid6/test/Makefile
+++ b/lib/raid6/test/Makefile
@@ -65,7 +65,7 @@ else ifeq ($(HAS_ALTIVEC),yes)
OBJS += altivec1.o altivec2.o altivec4.o altivec8.o \
vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
else ifeq ($(ARCH),loongarch64)
- OBJS += loongarch_simd.o
+ OBJS += loongarch_simd.o recov_loongarch_simd.o
endif
.c.o:


Kind regards,

Paul


PS: I brought up the raid speed tests in the past, and Borislav called them a random number generator [1]. ;-)


[1]: https://lore.kernel.org/all/20210406124126.GM17806@xxxxxxx/