From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=proton.me Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=proton.me header.i=@proton.me header.a=rsa-sha256 header.s=protonmail header.b=RmNTzv8X; dkim-atps=neutral Received: from mail-10699.protonmail.ch (mail-10699.protonmail.ch [79.135.106.99]) by passt.top (Postfix) with ESMTPS id 968BF5A004E for ; Wed, 11 Feb 2026 12:55:27 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1770810926; x=1771070126; bh=8O88AdgsTzkbHdBS3Aqx3g8rZNIvvt2YX4z8vvZsBJ8=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=RmNTzv8XoNFfIhNm0MKu6jrMfSIYO/ZizaYK6FDtfpDOlJzFOO6sI5INLlGwKBE81 h2ZYvwVyJ3ZdtN5UK5ib7uiEyggptyvckjSosLP+GRmCht2HhG7Wymm4k5BdYpiyPi +YPgko7Tyr4nzDXABlI8zqEakG+B6Fk0nmLyrP3xyYgjYI+p/Jaq+ypHCt6IO+JtjF Fj7V1MehzBlLlV/wIllD2foucEkjgQ7R4aSEi4ZEudde6KzK6qU9audsCoaU0GcFCw Mb3xeDeQK1EDJyntSgiFVfY1pxTT8pDb4d8RedF3VWD8VvhrTX3KXrRvoCTtK/TwsP wYpxJrEjqeNzg== Date: Wed, 11 Feb 2026 11:55:22 +0000 To: =?utf-8?Q?C=C3=A9dric_Le_Goater?= From: jfiusdq Subject: Re: checksum: add VSX fast path for POWER8/POWER9 Message-ID: In-Reply-To: References: <5LdZey3mMxwwzujKCRhh-ZEiJi9nQZTX4Q9YabzgvpDN3XkjpaDXWgfUiS7ig1SlB2HCy7ecA1V6bx5F1rhdpuoElNFGZ7i0Z9TccLSms7U=@proton.me> <00b3e4a1-005b-46a5-b6ce-bf444be9b72d@redhat.com> Feedback-ID: 167378330:user:proton X-Pm-Message-ID: 1dd80bb1fa6a439332ce2671561fff5c4a1a3bc9 MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=pgp-sha512; boundary="------f1f65f68ef5166db0e45bd1d41f6f8d6ab50c39cf9e7a3f38493eb5a44d47268"; charset=utf-8 X-MailFrom: jfiusdq@proton.me X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation Message-ID-Hash: PCBP3DJTCUT7T7O5RONGGXNTXEY7HN57 X-Message-ID-Hash: PCBP3DJTCUT7T7O5RONGGXNTXEY7HN57 X-Mailman-Approved-At: Wed, 11 Feb 2026 13:49:47 +0100 CC: Laurent Vivier , passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --------f1f65f68ef5166db0e45bd1d41f6f8d6ab50c39cf9e7a3f38493eb5a44d47268 Content-Type: multipart/mixed;boundary=---------------------86a74573781d6b2505f9d59620ab3f9e -----------------------86a74573781d6b2505f9d59620ab3f9e Content-Transfer-Encoding: quoted-printable Content-Type: text/plain;charset=utf-8 // bench_checksum.c // Run from the source directory: // gcc -O3 -D_GNU_SOURCE -mcpu=3Dpower9 -mvsx -maltivec \ // -I . -o /tmp/bench_vsx bench_checksum.c checksum.c // // gcc -O3 -D_GNU_SOURCE -mcpu=3Dpower9 -mno-vsx -mno-altivec -fno-tree-ve= ctorize \ // -U__POWER8_VECTOR__ -U__POWER9_VECTOR__ \ // -I . -o /tmp/bench_scalar bench_checksum.c checksum.c #include #include #include #include #include "checksum.h" static double now_sec(void) { struct timespec ts; clock_gettime(CLOCK_MONOTONIC, &ts); return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9; } int main(void) { static const size_t sizes[] =3D { 64, 256, 1500, 16 * 1024, 64 * 1024 }; const size_t target_bytes =3D 512UL * 1024UL * 1024UL; /* 512 MiB per siz= e */ uint8_t *buf =3D NULL; size_t i; volatile uint32_t sink =3D 0; if (posix_memalign((void **)&buf, 64, sizes[sizeof(sizes) / sizeof(sizes[0]) - 1])) { perror("posix_memalign"); return 1; } for (i =3D 0; i < sizes[sizeof(sizes) / sizeof(sizes[0]) - 1]; i++) buf[i] =3D (uint8_t)(i * 131u + 7u); printf("len, iters, seconds, GBps, checksum\n"); for (i =3D 0; i < sizeof(sizes) / sizeof(sizes[0]); i++) { size_t len =3D sizes[i]; size_t iters =3D target_bytes / len; size_t warm =3D iters / 10; double start, end, secs, gbps; if (iters < 10000) iters =3D 10000; if (warm < 1000) warm =3D 1000; for (size_t j =3D 0; j < warm; j++) sink ^=3D csum_unfolded(buf, len, 0); start =3D now_sec(); for (size_t j =3D 0; j < iters; j++) sink ^=3D csum_unfolded(buf, len, 0); end =3D now_sec(); secs =3D end - start; gbps =3D ((double)len * (double)iters) / (secs * 1e9); printf("%zu, %zu, %.6f, %.3f, 0x%08x\n", len, iters, secs, gbps, sink); } free((void *)buf); return 0; } On Tuesday, February 10th, 2026 at 1:37 PM, C=C3=A9dric Le Goater wrote: > Hi, > = > On 2/7/26 23:31, jfiusdq wrote: > > Microbenchmark of the checksum function vs C version at different buff= er sizes: > > > > > > Results (GB/s, higher is better; speedup =3D VSX / scalar): > > > > 64B: VSX 4.61 vs scalar 5.91 -> 0.78x (VSX slower for tiny buffers) > > 256B: VSX 10.91 vs scalar 7.57 -> 1.44x > > 1500B: VSX 13.88 vs scalar 6.89 -> 2.02x > > 16KB: VSX 14.53 vs scalar 6.96 -> 2.09x > > 64KB: VSX 15.15 vs scalar 6.85 -> 2.21x > = > Could you please share Microbenchmark ? > = > Thanks, > = > C. > = > = > > On Friday, February 6th, 2026 at 3:17 PM, Laurent Vivier wrote: > > > >> > > > >> > > > >> On Thu, 05 Feb 2026 06:14:40 +0000, jfiusdq jfiusdq@proton.me wrote: > >> > > > >>> Tested with podman on Debian 13 for a while and works ok. It's > >>> difficult to run all the tests on POWER but 505-networking-pasta.bat= s > >>> test suite passes. > >>> --- > >>> checksum.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++= -- > >>> 1 file changed, 107 insertions(+), 3 deletions(-) > >>> > > > >>> diff --git a/checksum.c b/checksum.c > >>> index 0c3837c..828f9ec 100644 > >>> --- a/checksum.c > >>> +++ b/checksum.c > >>> @@ -281,7 +281,7 @@ void csum_icmp6(struct icmp6hdr *icmp6hr, > >>> icmp6hr->icmp6_cksum =3D csum(payload, dlen, psum); > >>> } > >>> > > > >>> -#ifdef AVX2 > >>> +#if defined(AVX2) > >>> #include > >>> > > > >>> /** > >>> @@ -479,7 +479,111 @@ uint32_t csum_unfolded(const void *buf, size_t= len, uint32_t init) > >>> > > > >>> return init; > >>> } > >>> -#else /* AVX2 / > >>> +#elif defined(POWER9_VECTOR) || defined(POWER8_VECTOR) > >>> +#include > >>> + > >>> +/* > >>> + * csum_vsx() - Compute 32-bit checksum using VSX SIMD instructions > >>> + * @buf: Input buffer > >>> + * @len: Input length > >>> + * @init: Initial 32-bit checksum, 0 for no pre-computed checksum > >>> + * > >>> + * Return: 32-bit checksum, not complemented, not folded > >>> + / > >>> +/ NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) / > >>> +attribute((optimize("-fno-strict-aliasing"))) / See csum_16b() */ > >>> +static uint32_t csum_vsx(const void buf, size_t len, uint32_t init) > >>> +{ > >>> + const uint8_t p =3D buf; > >>> + vector unsigned int sum_even =3D vec_splat_u32(0); > >>> + vector unsigned int sum_odd =3D vec_splat_u32(0); > >>> + const vector unsigned short ones =3D vec_splat_u16(1); > >>> + uint64_t sum64 =3D init; > >>> + > >>> +#ifdef POWER9_VECTOR > >>> + while (len >=3D 64) { > >>> + vector unsigned char v0b =3D vec_vsx_ld(0, p); > >>> + vector unsigned char v1b =3D vec_vsx_ld(16, p); > >>> + vector unsigned char v2b =3D vec_vsx_ld(32, p); > >>> + vector unsigned char v3b =3D vec_vsx_ld(48, p); > >>> + vector unsigned short v0 =3D (vector unsigned short)v0b; > >>> + vector unsigned short v1 =3D (vector unsigned short)v1b; > >>> + vector unsigned short v2 =3D (vector unsigned short)v2b; > >>> + vector unsigned short v3 =3D (vector unsigned short)v3b; > >>> + > >>> + sum_even =3D vec_add(sum_even, vec_mule(v0, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v0, ones)); > >>> + sum_even =3D vec_add(sum_even, vec_mule(v1, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v1, ones)); > >>> + sum_even =3D vec_add(sum_even, vec_mule(v2, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v2, ones)); > >>> + sum_even =3D vec_add(sum_even, vec_mule(v3, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v3, ones)); > >>> + > >>> + p +=3D 64; > >>> + len -=3D 64; > >>> + } > >>> +#endif > >>> + > >>> + while (len >=3D 32) { > >>> + vector unsigned char v0b =3D vec_vsx_ld(0, p); > >>> + vector unsigned char v1b =3D vec_vsx_ld(16, p); > >>> + vector unsigned short v0 =3D (vector unsigned short)v0b; > >>> + vector unsigned short v1 =3D (vector unsigned short)v1b; > >>> + > >>> + sum_even =3D vec_add(sum_even, vec_mule(v0, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v0, ones)); > >>> + sum_even =3D vec_add(sum_even, vec_mule(v1, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v1, ones)); > >>> + > >>> + p +=3D 32; > >>> + len -=3D 32; > >>> + } > >>> + > >>> + while (len >=3D 16) { > >>> + vector unsigned char v0b =3D vec_vsx_ld(0, p); > >>> + vector unsigned short v0 =3D (vector unsigned short)v0b; > >>> + > >>> + sum_even =3D vec_add(sum_even, vec_mule(v0, ones)); > >>> + sum_odd =3D vec_add(sum_odd, vec_mulo(v0, ones)); > >>> + > >>> + p +=3D 16; > >>> + len -=3D 16; > >>> + } > >>> + > >>> + { > >>> + vector unsigned int sum32 =3D vec_add(sum_even, sum_odd); > >>> + uint32_t partial[4] attribute((aligned(16))); > >>> + > >>> + vec_st(sum32, 0, partial); > >>> + sum64 +=3D (uint64_t)partial[0] + partial[1] + > >>> + partial[2] + partial[3]; > >>> + } > >>> + > >>> + sum64 +=3D sum_16b(p, len); > >>> + > >>> + sum64 =3D (sum64 >> 32) + (sum64 & 0xffffffff); > >>> + sum64 +=3D sum64 >> 32; > >>> + > >>> + return (uint32_t)sum64; > >>> +} > >>> + > >>> +/ > >>> + * csum_unfolded() - Calculate the unfolded checksum of a data buff= er. > >>> + * > >>> + * @buf: Input buffer > >>> + * @len: Input length > >>> + * @init: Initial 32-bit checksum, 0 for no pre-computed checksum > >>> + * > >>> + * Return: 32-bit unfolded checksum > >>> + / > >>> +/ NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) / > >>> +attribute((optimize("-fno-strict-aliasing"))) / See csum_16b() / > >>> +uint32_t csum_unfolded(const void buf, size_t len, uint32_t init) > >>> +{ > >>> + return csum_vsx(buf, len, init); > >>> +} > >>> +#else / !AVX2 && !POWER9_VECTOR && !POWER8_VECTOR / > >>> / > >>> * csum_unfolded() - Calculate the unfolded checksum of a data buffer= . > >>> * > >>> @@ -495,7 +599,7 @@ uint32_t csum_unfolded(const void buf, size_t le= n, uint32_t init) > >>> { > >>> return sum_16b(buf, len) + init; > >>> } > >>> -#endif / !AVX2 / > >>> +#endif / !AVX2 && !POWER9_VECTOR && !POWER8_VECTOR */ > >>> > > > >>> /** > >>> * csum_iov_tail() - Calculate unfolded checksum for the tail of an I= O vector > >>> -- > >>> 2.52.0 > >> > > > >> > > > >> Reviewed-by: Laurent Vivier lvivier@redhat.com > = > = -----------------------86a74573781d6b2505f9d59620ab3f9e Content-Type: application/pgp-keys; filename="publickey - jfiusdq@proton.me - 0x344F580A.asc"; name="publickey - jfiusdq@proton.me - 0x344F580A.asc" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="publickey - jfiusdq@proton.me - 0x344F580A.asc"; name="publickey - jfiusdq@proton.me - 0x344F580A.asc" LS0tLS1CRUdJTiBQR1AgUFVCTElDIEtFWSBCTE9DSy0tLS0tCgp4ak1FYVJXRTZ4WUpLd1lCQkFI YVJ3OEJBUWRBZi92VUlPRVlEcjl2OHZEQ1RicVlJdnhoUlJ0MjBhTm8KMTF1OUVuVGdyQ0hOSldw bWFYVnpaSEZBY0hKdmRHOXVMbTFsSUR4cVptbDFjMlJ4UUhCeWIzUnZiaTV0ClpUN0N3QkVFRXhZ S0FJTUZnbWtWaE9zREN3a0hDUkR0dzkxdmxVeGhSRVVVQUFBQUFBQWNBQ0J6WVd4MApRRzV2ZEdG MGFXOXVjeTV2Y0dWdWNHZHdhbk11YjNKbk5wY3RzQ0hKRjBqUEZLY3Vod1lCQ1hMZ2Y0S28KZHFy OWdXSmR4bVVPem5jREZRb0lCQllBQWdFQ0dRRUNtd01DSGdFV0lRUTBUMWdLY2hVRDBBWUZvajN0 Cnc5MXZsVXhoUkFBQWorWUEvMlFSRmkvOElBNFU4YWszNVBmN1hDWHdRQkxpTUZDUW16MDhYOWs1 SkNkZgpBUDBSWUpIWHdoZGZ1WUZBT0dsaE9iVzFQejBBM2FLM2dUa09SbE1VSTk5YURzNDRCR2tW aE9zU0Npc0cKQVFRQmwxVUJCUUVCQjBDbmlSQ21tN0MrV2tOaXk5RVcrZFo4MHhsRnZqbk90MXRj TkdrZUJDUVhOUU1CCkNBZkN2Z1FZRmdvQWNBV0NhUldFNndrUTdjUGRiNVZNWVVSRkZBQUFBQUFB SEFBZ2MyRnNkRUJ1YjNSaApkR2x2Ym5NdWIzQmxibkJuY0dwekxtOXlaNUVQUDJ6b3diOG9zZUFP MjRKQjdhMGxRWEVSZnJWK0t4Wm8KM214bldMdldBcHNNRmlFRU5FOVlDbklWQTlBR0JhSTk3Y1Bk YjVWTVlVUUFBQTdRQVAwWjcreHdQRU9hCmpnT3FKR0Z0TEN1M1hsUXhJNUVKSThxdElMc3Z2Vk5i dGdEK01UdjNJeGRvRmUrWmkxeGxnaGd3cjRBYwppdENwamlRL21Jc2lWTXlQb1EwPQo9U2tMTQot LS0tLUVORCBQR1AgUFVCTElDIEtFWSBCTE9DSy0tLS0tCg== -----------------------86a74573781d6b2505f9d59620ab3f9e-- --------f1f65f68ef5166db0e45bd1d41f6f8d6ab50c39cf9e7a3f38493eb5a44d47268 Content-Type: application/pgp-signature; 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