From patchwork Thu Jun 17 16:51:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 12328901 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7428D6D00 for ; Thu, 17 Jun 2021 16:51:41 +0000 (UTC) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 15HGZq2F074247; Thu, 17 Jun 2021 12:51:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=pp1; bh=FlhfHB+EdYRiNZqvUGZDruM5K475E9IQTOeE10vgabk=; b=Z7rDyjLC0qxU0LOuLL7qwTnRp783C4IsgNwcomL4vQz83o4Is/56GdyJFMG1CJwJJzC+ LxyUASVNI39Y59t2+vBQpZILebR9qcQQ0yFK5z6nfe/sSR++6j4cW+4okb22Nr8le6gS quLeb9JgEvouhJiA5N/2YpkyaW2NzZsl6hMzFfzbVx5FXY1NMKk5W3+2aSLXVqTy41Tr EaR+YqDldB+r2gIskER8JMuvDCjuG5ixwxsZWU7XkZ4PyGVv+mrNXH7GhhJMZA7kLqBM OReOVLH+12QajK03/i53WHFv2ZNZoUT2FxvIyZhto+lqF+EkBQkbwRnibNfsMr5xSf63 Cw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 3987hrpfks-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Jun 2021 12:51:38 -0400 Received: from m0098410.ppops.net (m0098410.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 15HGaZsi077611; Thu, 17 Jun 2021 12:51:37 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 3987hrpfkc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Jun 2021 12:51:37 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 15HGlWAt028358; Thu, 17 Jun 2021 16:51:36 GMT Received: from b01cxnp23033.gho.pok.ibm.com (b01cxnp23033.gho.pok.ibm.com [9.57.198.28]) by ppma01wdc.us.ibm.com with ESMTP id 394mj9tkvx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Jun 2021 16:51:36 +0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp23033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 15HGpZRa40632742 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 17 Jun 2021 16:51:36 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E03ABB206B; Thu, 17 Jun 2021 16:51:35 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E450EB205F; Thu, 17 Jun 2021 16:51:32 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.199.39.101]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Thu, 17 Jun 2021 16:51:32 +0000 (GMT) From: "Aneesh Kumar K.V" To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au Cc: Nathan Lynch , David Gibson , Daniel Henrique Barboza , nvdimm@lists.linux.dev, dan.j.williams@intel.com, "Aneesh Kumar K.V" Subject: [PATCH v4 7/7] powerpc/pseries: Add support for FORM2 associativity Date: Thu, 17 Jun 2021 22:21:05 +0530 Message-Id: <20210617165105.574178-8-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210617165105.574178-1-aneesh.kumar@linux.ibm.com> References: <20210617165105.574178-1-aneesh.kumar@linux.ibm.com> X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 6jZuql_KlN_SwvgYIJkVtRpTivYklibY X-Proofpoint-ORIG-GUID: W0LcxiCqg3oPV7VqriUVcEgZfIgdINS1 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-06-17_15:2021-06-15,2021-06-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 phishscore=0 spamscore=0 impostorscore=0 mlxlogscore=999 clxscore=1015 priorityscore=1501 lowpriorityscore=0 bulkscore=0 mlxscore=0 adultscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2106170104 PAPR interface currently supports two different ways of communicating resource grouping details to the OS. These are referred to as Form 0 and Form 1 associativity grouping. Form 0 is the older format and is now considered deprecated. This patch adds another resource grouping named FORM2. Signed-off-by: Daniel Henrique Barboza Signed-off-by: Aneesh Kumar K.V --- Documentation/powerpc/associativity.rst | 135 ++++++++++++++++++++ arch/powerpc/include/asm/firmware.h | 3 +- arch/powerpc/include/asm/prom.h | 1 + arch/powerpc/kernel/prom_init.c | 3 +- arch/powerpc/mm/numa.c | 149 +++++++++++++++++++++- arch/powerpc/platforms/pseries/firmware.c | 1 + 6 files changed, 286 insertions(+), 6 deletions(-) create mode 100644 Documentation/powerpc/associativity.rst diff --git a/Documentation/powerpc/associativity.rst b/Documentation/powerpc/associativity.rst new file mode 100644 index 000000000000..93be604ac54d --- /dev/null +++ b/Documentation/powerpc/associativity.rst @@ -0,0 +1,135 @@ +============================ +NUMA resource associativity +============================= + +Associativity represents the groupings of the various platform resources into +domains of substantially similar mean performance relative to resources outside +of that domain. Resources subsets of a given domain that exhibit better +performance relative to each other than relative to other resources subsets +are represented as being members of a sub-grouping domain. This performance +characteristic is presented in terms of NUMA node distance within the Linux kernel. +From the platform view, these groups are also referred to as domains. + +PAPR interface currently supports different ways of communicating these resource +grouping details to the OS. These are referred to as Form 0, Form 1 and Form2 +associativity grouping. Form 0 is the older format and is now considered deprecated. + +Hypervisor indicates the type/form of associativity used via "ibm,arcitecture-vec-5 property". +Bit 0 of byte 5 in the "ibm,architecture-vec-5" property indicates usage of Form 0 or Form 1. +A value of 1 indicates the usage of Form 1 associativity. For Form 2 associativity +bit 2 of byte 5 in the "ibm,architecture-vec-5" property is used. + +Form 0 +----- +Form 0 associativity supports only two NUMA distance (LOCAL and REMOTE). + +Form 1 +----- +With Form 1 a combination of ibm,associativity-reference-points and ibm,associativity +device tree properties are used to determine the NUMA distance between resource groups/domains. + +The “ibm,associativity” property contains one or more lists of numbers (domainID) +representing the resource’s platform grouping domains. + +The “ibm,associativity-reference-points” property contains one or more list of numbers +(domainID index) that represents the 1 based ordinal in the associativity lists. +The list of domainID index represnets increasing hierachy of resource grouping. + +ex: +{ primary domainID index, secondary domainID index, tertiary domainID index.. } + +Linux kernel uses the domainID at the primary domainID index as the NUMA node id. +Linux kernel computes NUMA distance between two domains by recursively comparing +if they belong to the same higher-level domains. For mismatch at every higher +level of the resource group, the kernel doubles the NUMA distance between the +comparing domains. + +Form 2 +------- +Form 2 associativity format adds separate device tree properties representing NUMA node distance +thereby making the node distance computation flexible. Form 2 also allows flexible primary +domain numbering. With numa distance computation now detached from the index value of +"ibm,associativity" property, Form 2 allows a large number of primary domain ids at the +same domainID index representing resource groups of different performance/latency characteristics. + +Hypervisor indicates the usage of FORM2 associativity using bit 2 of byte 5 in the +"ibm,architecture-vec-5" property. + +"ibm,numa-lookup-index-table" property contains one or more list numbers representing +the domainIDs present in the system. The offset of the domainID in this property is considered +the domainID index. + +prop-encoded-array: The number N of the domainIDs encoded as with encode-int, followed by +N domainID encoded as with encode-int + +For ex: +ibm,numa-lookup-index-table = {4, 0, 8, 250, 252}, domainID index for domainID 8 is 1. + +"ibm,numa-distance-table" property contains one or more list of numbers representing the NUMA +distance between resource groups/domains present in the system. + +prop-encoded-array: The number N of the distance values encoded as with encode-int, followed by +N distance values encoded as with encode-bytes. The max distance value we could encode is 255. + +For ex: +ibm,numa-lookup-index-table = {3, 0, 8, 40} +ibm,numa-distance-table = {9, 10, 20, 80, 20, 10, 160, 80, 160, 10} + + | 0 8 40 +--|------------ + | +0 | 10 20 80 + | +8 | 20 10 160 + | +40| 80 160 10 + + +"ibm,associativity" property for resources in node 0, 8 and 40 + +{ 3, 6, 7, 0 } +{ 3, 6, 9, 8 } +{ 3, 6, 7, 40} + +With "ibm,associativity-reference-points" { 0x3 } + +Each resource (drcIndex) now also supports additional optional device tree properties. +These properties are marked optional because the platform can choose not to export +them and provide the system topology details using the earlier defined device tree +properties alone. The optional device tree properties are used when adding new resources +(DLPAR) and when the platform didn't provide the topology details of the domain which +contains the newly added resource during boot. + +"ibm,numa-lookup-index" property contains a number representing the domainID index to be used +when building the NUMA distance of the numa node to which this resource belongs. This can +be looked at as the index at which this new domainID would have appeared in +"ibm,numa-lookup-index-table" if the domain was present during boot. The domainID +of the new resource can be obtained from the existing "ibm,associativity" property. This +can be used to build distance information of a newly onlined NUMA node via DLPAR operation. +The value is 1 based array index value. + +prop-encoded-array: An integer encoded as with encode-int specifying the domainID index + +"ibm,numa-distance" property contains one or more list of numbers presenting the NUMA distance +from this resource domain to other resources. + +prop-encoded-array: The number N of the distance values encoded as with encode-int, followed by +N distance values encoded as with encode-bytes. The max distance value we could encode is 255. + +For ex: +ibm,associativity = { 4, 5, 10, 50} +ibm,numa-lookup-index = { 4 } +ibm,numa-distance = {8, 160, 255, 80, 10, 160, 255, 80, 10} + +resulting in a new toplogy as below. + | 0 8 40 50 +--|------------------ + | +0 | 10 20 80 160 + | +8 | 20 10 160 255 + | +40| 80 160 10 80 + | +50| 160 255 80 10 + diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h index 60b631161360..97a3bd9ffeb9 100644 --- a/arch/powerpc/include/asm/firmware.h +++ b/arch/powerpc/include/asm/firmware.h @@ -53,6 +53,7 @@ #define FW_FEATURE_ULTRAVISOR ASM_CONST(0x0000004000000000) #define FW_FEATURE_STUFF_TCE ASM_CONST(0x0000008000000000) #define FW_FEATURE_RPT_INVALIDATE ASM_CONST(0x0000010000000000) +#define FW_FEATURE_FORM2_AFFINITY ASM_CONST(0x0000020000000000) #ifndef __ASSEMBLY__ @@ -73,7 +74,7 @@ enum { FW_FEATURE_HPT_RESIZE | FW_FEATURE_DRMEM_V2 | FW_FEATURE_DRC_INFO | FW_FEATURE_BLOCK_REMOVE | FW_FEATURE_PAPR_SCM | FW_FEATURE_ULTRAVISOR | - FW_FEATURE_RPT_INVALIDATE, + FW_FEATURE_RPT_INVALIDATE | FW_FEATURE_FORM2_AFFINITY, FW_FEATURE_PSERIES_ALWAYS = 0, FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_ULTRAVISOR, FW_FEATURE_POWERNV_ALWAYS = 0, diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h index df9fec9d232c..5c80152e8f18 100644 --- a/arch/powerpc/include/asm/prom.h +++ b/arch/powerpc/include/asm/prom.h @@ -149,6 +149,7 @@ extern int of_read_drc_info_cell(struct property **prop, #define OV5_XCMO 0x0440 /* Page Coalescing */ #define OV5_FORM1_AFFINITY 0x0580 /* FORM1 NUMA affinity */ #define OV5_PRRN 0x0540 /* Platform Resource Reassignment */ +#define OV5_FORM2_AFFINITY 0x0520 /* Form2 NUMA affinity */ #define OV5_HP_EVT 0x0604 /* Hot Plug Event support */ #define OV5_RESIZE_HPT 0x0601 /* Hash Page Table resizing */ #define OV5_PFO_HW_RNG 0x1180 /* PFO Random Number Generator */ diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index 64b9593038a7..496fdac54c29 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -1070,7 +1070,8 @@ static const struct ibm_arch_vec ibm_architecture_vec_template __initconst = { #else 0, #endif - .associativity = OV5_FEAT(OV5_FORM1_AFFINITY) | OV5_FEAT(OV5_PRRN), + .associativity = OV5_FEAT(OV5_FORM1_AFFINITY) | OV5_FEAT(OV5_PRRN) | + OV5_FEAT(OV5_FORM2_AFFINITY), .bin_opts = OV5_FEAT(OV5_RESIZE_HPT) | OV5_FEAT(OV5_HP_EVT), .micro_checkpoint = 0, .reserved0 = 0, diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index d32729f235b8..5a7d94960fb7 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -56,12 +56,17 @@ static int n_mem_addr_cells, n_mem_size_cells; #define FORM0_AFFINITY 0 #define FORM1_AFFINITY 1 +#define FORM2_AFFINITY 2 static int affinity_form; #define MAX_DISTANCE_REF_POINTS 4 static int max_associativity_domain_index; static const __be32 *distance_ref_points; static int distance_lookup_table[MAX_NUMNODES][MAX_DISTANCE_REF_POINTS]; +static int numa_distance_table[MAX_NUMNODES][MAX_NUMNODES] = { + [0 ... MAX_NUMNODES - 1] = { [0 ... MAX_NUMNODES - 1] = -1 } +}; +static int numa_id_index_table[MAX_NUMNODES]; /* * Allocate node_to_cpumask_map based on number of available nodes @@ -166,6 +171,27 @@ static void unmap_cpu_from_node(unsigned long cpu) } #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */ +/* + * With FORM2 if we are not using logical domain ids, we will find + * both primary and seconday domains with same value. Hence always + * start comparison from secondary domains + */ +static int __cpu_form2_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) +{ + int dist = 0; + + int i, index; + + for (i = 1; i < max_associativity_domain_index; i++) { + index = be32_to_cpu(distance_ref_points[i]); + if (cpu1_assoc[index] == cpu2_assoc[index]) + break; + dist++; + } + + return dist; +} + static int __cpu_form1_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) { int dist = 0; @@ -178,7 +204,6 @@ static int __cpu_form1_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) break; dist++; } - return dist; } @@ -186,8 +211,9 @@ int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) { /* We should not get called with FORM0 */ VM_WARN_ON(affinity_form == FORM0_AFFINITY); - - return __cpu_form1_distance(cpu1_assoc, cpu2_assoc); + if (affinity_form == FORM1_AFFINITY) + return __cpu_form1_distance(cpu1_assoc, cpu2_assoc); + return __cpu_form2_distance(cpu1_assoc, cpu2_assoc); } /* must hold reference to node during call */ @@ -201,7 +227,9 @@ int __node_distance(int a, int b) int i; int distance = LOCAL_DISTANCE; - if (affinity_form == FORM0_AFFINITY) + if (affinity_form == FORM2_AFFINITY) + return numa_distance_table[a][b]; + else if (affinity_form == FORM0_AFFINITY) return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE); for (i = 0; i < max_associativity_domain_index; i++) { @@ -303,15 +331,116 @@ static void initialize_form1_numa_distance(struct device_node *node) /* * Used to update distance information w.r.t newly added node. + * ibm,numa-lookup-index -> 4 + * ibm,numa-distance -> {5, 20, 40, 60, 80, 10 } */ void update_numa_distance(struct device_node *node) { + int i, nid, other_nid, other_nid_index = 0; + const __be32 *numa_indexp; + const __u8 *numa_distancep; + int numa_index, max_numa_index, numa_distance; + if (affinity_form == FORM0_AFFINITY) return; else if (affinity_form == FORM1_AFFINITY) { initialize_form1_numa_distance(node); return; } + /* FORM2 affinity */ + + nid = of_node_to_nid_single(node); + if (nid == NUMA_NO_NODE) + return; + + /* Already initialized */ + if (numa_distance_table[nid][nid] != -1) + return; + /* + * update node distance if not already populated. + */ + numa_distancep = of_get_property(node, "ibm,numa-distance", NULL); + if (!numa_distancep) + return; + + numa_indexp = of_get_property(node, "ibm,numa-lookup-index", NULL); + if (!numa_indexp) + return; + + numa_index = of_read_number(numa_indexp, 1); + /* + * update the numa_id_index_table. Device tree look at index table as + * 1 based array indexing. + */ + numa_id_index_table[numa_index - 1] = nid; + + max_numa_index = of_read_number((const __be32 *)numa_distancep, 1); + VM_WARN_ON(max_numa_index != 2 * numa_index); + /* Skip the size which is encoded int */ + numa_distancep += sizeof(__be32); + + /* + * First fill the distance information from other node to this node. + */ + other_nid_index = 0; + for (i = 0; i < numa_index; i++) { + numa_distance = numa_distancep[i]; + other_nid = numa_id_index_table[other_nid_index++]; + numa_distance_table[other_nid][nid] = numa_distance; + } + + other_nid_index = 0; + for (; i < max_numa_index; i++) { + numa_distance = numa_distancep[i]; + other_nid = numa_id_index_table[other_nid_index++]; + numa_distance_table[nid][other_nid] = numa_distance; + } +} + +/* + * ibm,numa-lookup-index-table= {N, domainid1, domainid2, ..... domainidN} + * ibm,numa-distance-table = { N, 1, 2, 4, 5, 1, 6, .... N elements} + */ +static void initialize_form2_numa_distance_lookup_table(struct device_node *root) +{ + const __u8 *numa_dist_table; + const __be32 *numa_lookup_index; + int numa_dist_table_length; + int max_numa_index, distance_index; + int i, curr_row = 0, curr_column = 0; + + numa_lookup_index = of_get_property(root, "ibm,numa-lookup-index-table", NULL); + max_numa_index = of_read_number(&numa_lookup_index[0], 1); + + /* first element of the array is the size and is encode-int */ + numa_dist_table = of_get_property(root, "ibm,numa-distance-table", NULL); + numa_dist_table_length = of_read_number((const __be32 *)&numa_dist_table[0], 1); + /* Skip the size which is encoded int */ + numa_dist_table += sizeof(__be32); + + pr_debug("numa_dist_table_len = %d, numa_dist_indexes_len = %d \n", + numa_dist_table_length, max_numa_index); + + for (i = 0; i < max_numa_index; i++) + /* +1 skip the max_numa_index in the property */ + numa_id_index_table[i] = of_read_number(&numa_lookup_index[i + 1], 1); + + + VM_WARN_ON(numa_dist_table_length != max_numa_index * max_numa_index); + + for (distance_index = 0; distance_index < numa_dist_table_length; distance_index++) { + int nodeA = numa_id_index_table[curr_row]; + int nodeB = numa_id_index_table[curr_column++]; + + numa_distance_table[nodeA][nodeB] = numa_dist_table[distance_index]; + + pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, numa_distance_table[nodeA][nodeB]); + if (curr_column >= max_numa_index) { + curr_row++; + /* reset the column */ + curr_column = 0; + } + } } static int __init find_primary_domain_index(void) @@ -324,6 +453,9 @@ static int __init find_primary_domain_index(void) */ if (firmware_has_feature(FW_FEATURE_OPAL)) { affinity_form = FORM1_AFFINITY; + } else if (firmware_has_feature(FW_FEATURE_FORM2_AFFINITY)) { + dbg("Using form 2 affinity\n"); + affinity_form = FORM2_AFFINITY; } else if (firmware_has_feature(FW_FEATURE_FORM1_AFFINITY)) { dbg("Using form 1 affinity\n"); affinity_form = FORM1_AFFINITY; @@ -368,8 +500,17 @@ static int __init find_primary_domain_index(void) index = of_read_number(&distance_ref_points[1], 1); } else { + /* + * Both FORM1 and FORM2 affinity find the primary domain details + * at the same offset. + */ index = of_read_number(distance_ref_points, 1); } + /* + * If it is FORM2 also initialize the distance table here. + */ + if (affinity_form == FORM2_AFFINITY) + initialize_form2_numa_distance_lookup_table(root); /* * Warn and cap if the hardware supports more than diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c index 5d4c2bc20bba..f162156b7b68 100644 --- a/arch/powerpc/platforms/pseries/firmware.c +++ b/arch/powerpc/platforms/pseries/firmware.c @@ -123,6 +123,7 @@ vec5_fw_features_table[] = { {FW_FEATURE_PRRN, OV5_PRRN}, {FW_FEATURE_DRMEM_V2, OV5_DRMEM_V2}, {FW_FEATURE_DRC_INFO, OV5_DRC_INFO}, + {FW_FEATURE_FORM2_AFFINITY, OV5_FORM2_AFFINITY}, }; static void __init fw_vec5_feature_init(const char *vec5, unsigned long len)