[PATCH v4] eal: allow worker lcore stacks to be allocated from hugepage memory
Kathleen Capella
Kathleen.Capella at arm.com
Tue May 24 00:35:03 CEST 2022
In this section of the code:
stack_ptr = rte_zmalloc_socket("lcore_stack",
stack_size,
stack_size,
rte_lcore_to_socket_id(lcore_id));
stack memory is aligned to the stack_size. According to the implementation of rte_zmalloc_socket, the alignment must be a power of two. If the user inputs a number of KBs that is not a power of two, this will fail with a generic error message of " EAL: Cannot allocate worker lcore stack memory." A check for this occurrence with a more descriptive error message and a note in the documentation would be good to include.
> -----Original Message-----
> From: Don Wallwork <donw at xsightlabs.com>
> Sent: Tuesday, May 17, 2022 10:32 AM
> To: dev at dpdk.org
> Cc: donw at xsightlabs.com; stephen at networkplumber.org;
> fengchengwen at huawei.com; mb at smartsharesystems.com;
> anatoly.burakov at intel.com; dmitry.kozliuk at gmail.com;
> bruce.richardson at intel.com; Honnappa Nagarahalli
> <Honnappa.Nagarahalli at arm.com>; nd <nd at arm.com>;
> haiyue.wang at intel.com
> Subject: [PATCH v4] eal: allow worker lcore stacks to be allocated from
> hugepage memory
>
> Add support for using hugepages for worker lcore stack memory. The intent
> is to improve performance by reducing stack memory related TLB misses and
> also by using memory local to the NUMA node of each lcore.
>
> EAL option '--huge-worker-stack [stack-size-in-kbytes]' is added to allow the
> feature to be enabled at runtime. If the size is not specified, the system
> pthread stack size will be used.
>
> Signed-off-by: Don Wallwork <donw at xsightlabs.com>
> Acked-by: Morten Brørup <mb at smartsharesystems.com>
> ---
> doc/guides/linux_gsg/eal_args.include.rst | 6 ++
> .../prog_guide/env_abstraction_layer.rst | 21 +++++++
> lib/eal/common/eal_common_options.c | 41 +++++++++++++
> lib/eal/common/eal_internal_cfg.h | 4 ++
> lib/eal/common/eal_options.h | 2 +
> lib/eal/linux/eal.c | 61 ++++++++++++++++++-
> 6 files changed, 133 insertions(+), 2 deletions(-)
>
> diff --git a/doc/guides/linux_gsg/eal_args.include.rst
> b/doc/guides/linux_gsg/eal_args.include.rst
> index 3549a0cf56..9cfbf7de84 100644
> --- a/doc/guides/linux_gsg/eal_args.include.rst
> +++ b/doc/guides/linux_gsg/eal_args.include.rst
> @@ -116,6 +116,12 @@ Memory-related options
>
> Force IOVA mode to a specific value.
>
> +* ``--huge-worker-stack[=size]``
> +
> + Allocate worker stack memory from hugepage memory. Stack size
> defaults
> + to system pthread stack size unless the optional size (in kbytes) is
> + specified.
> +
> Debugging options
> ~~~~~~~~~~~~~~~~~
>
> diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst
> b/doc/guides/prog_guide/env_abstraction_layer.rst
> index 5f0748fba1..e74516f0cf 100644
> --- a/doc/guides/prog_guide/env_abstraction_layer.rst
> +++ b/doc/guides/prog_guide/env_abstraction_layer.rst
> @@ -329,6 +329,27 @@ Another option is to use bigger page sizes. Since
> fewer pages are required to cover the same memory area, fewer file
> descriptors will be stored internally by EAL.
>
> +.. _huge-worker-stack:
> +
> +Hugepage Worker Stacks
> +^^^^^^^^^^^^^^^^^^^^^^
> +
> +When the ``--huge-worker-stack[=size]`` EAL option is specified, worker
> +thread stacks are allocated from hugepage memory local to the NUMA node
> +of the thread. Worker stack size defaults to system pthread stack size
> +if the optional size parameter is not specified.
> +
> +.. warning::
> + Stacks allocated from hugepage memory are not protected by guard
> + pages. Worker stacks must be sufficiently sized to prevent stack
> + overflow when this option is used.
> +
> + As with normal thread stacks, hugepage worker thread stack size is
> + fixed and is not dynamically resized. Therefore, an application that
> + is free of stack page faults under a given load should be safe with
> + hugepage worker thread stacks given the same thread stack size and
> + loading conditions.
> +
> Support for Externally Allocated Memory
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> diff --git a/lib/eal/common/eal_common_options.c
> b/lib/eal/common/eal_common_options.c
> index f247a42455..370801f19b 100644
> --- a/lib/eal/common/eal_common_options.c
> +++ b/lib/eal/common/eal_common_options.c
> @@ -103,6 +103,7 @@ eal_long_options[] = {
> {OPT_TELEMETRY, 0, NULL, OPT_TELEMETRY_NUM },
> {OPT_NO_TELEMETRY, 0, NULL, OPT_NO_TELEMETRY_NUM },
> {OPT_FORCE_MAX_SIMD_BITWIDTH, 1, NULL,
> OPT_FORCE_MAX_SIMD_BITWIDTH_NUM},
> + {OPT_HUGE_WORKER_STACK, 2, NULL,
> OPT_HUGE_WORKER_STACK_NUM },
>
> {0, 0, NULL, 0 }
> };
> @@ -1618,6 +1619,28 @@ eal_parse_huge_unlink(const char *arg, struct
> hugepage_file_discipline *out)
> return -1;
> }
>
> +#ifndef RTE_EXEC_ENV_WINDOWS
> +static int
> +eal_parse_huge_worker_stack(const char *arg, size_t
> +*huge_worker_stack_size) {
> + size_t worker_stack_size;
> + char *end;
> +
> + if (arg == NULL || arg[0] == '\0') {
> + *huge_worker_stack_size = WORKER_STACK_SIZE_FROM_OS;
> + return 0;
> + }
> + errno = 0;
> + worker_stack_size = strtoul(arg, &end, 10);
> + if (errno || end == NULL || worker_stack_size == 0 ||
> + worker_stack_size >= (size_t)-1 / 1024)
> + return -1;
> +
> + *huge_worker_stack_size = worker_stack_size * 1024;
> + return 0;
> +}
> +#endif
> +
> int
> eal_parse_common_option(int opt, const char *optarg,
> struct internal_config *conf)
> @@ -1921,6 +1944,17 @@ eal_parse_common_option(int opt, const char
> *optarg,
> }
> break;
>
> +#ifndef RTE_EXEC_ENV_WINDOWS
> + case OPT_HUGE_WORKER_STACK_NUM:
> + if (eal_parse_huge_worker_stack(optarg,
> + &conf-
> >huge_worker_stack_size) < 0) {
> + RTE_LOG(ERR, EAL, "invalid parameter for --"
> + OPT_HUGE_WORKER_STACK"\n");
> + return -1;
> + }
> + break;
> +#endif /* !RTE_EXEC_ENV_WINDOWS */
> +
> /* don't know what to do, leave this to caller */
> default:
> return 1;
> @@ -2235,5 +2269,12 @@ eal_common_usage(void)
> " --"OPT_NO_PCI" Disable PCI\n"
> " --"OPT_NO_HPET" Disable HPET\n"
> " --"OPT_NO_SHCONF" No shared config (mmap'd files)\n"
> +#ifndef RTE_EXEC_ENV_WINDOWS
> + " --"OPT_HUGE_WORKER_STACK"[=size]\n"
> + " Allocate worker thread stacks from\n"
> + " hugepage memory. Size is in units of\n"
> + " kbytes and defaults to system thread\n"
> + " stack size if not specified.\n"
> +#endif
> "\n", RTE_MAX_LCORE);
> }
> diff --git a/lib/eal/common/eal_internal_cfg.h
> b/lib/eal/common/eal_internal_cfg.h
> index b71faadd18..5e154967e4 100644
> --- a/lib/eal/common/eal_internal_cfg.h
> +++ b/lib/eal/common/eal_internal_cfg.h
> @@ -48,6 +48,9 @@ struct hugepage_file_discipline {
> bool unlink_existing;
> };
>
> +/** Worker hugepage stack size should default to OS value. */ #define
> +WORKER_STACK_SIZE_FROM_OS ((size_t)~0)
> +
> /**
> * internal configuration
> */
> @@ -102,6 +105,7 @@ struct internal_config {
> unsigned int no_telemetry; /**< true to disable Telemetry */
> struct simd_bitwidth max_simd_bitwidth;
> /**< max simd bitwidth path to use */
> + size_t huge_worker_stack_size; /**< worker thread stack size */
> };
>
> void eal_reset_internal_config(struct internal_config *internal_cfg); diff --git
> a/lib/eal/common/eal_options.h b/lib/eal/common/eal_options.h index
> 8e4f7202a2..3cc9cb6412 100644
> --- a/lib/eal/common/eal_options.h
> +++ b/lib/eal/common/eal_options.h
> @@ -87,6 +87,8 @@ enum {
> OPT_NO_TELEMETRY_NUM,
> #define OPT_FORCE_MAX_SIMD_BITWIDTH "force-max-simd-bitwidth"
> OPT_FORCE_MAX_SIMD_BITWIDTH_NUM,
> +#define OPT_HUGE_WORKER_STACK "huge-worker-stack"
> + OPT_HUGE_WORKER_STACK_NUM,
>
> OPT_LONG_MAX_NUM
> };
> diff --git a/lib/eal/linux/eal.c b/lib/eal/linux/eal.c index
> 1ef263434a..2bee66577e 100644
> --- a/lib/eal/linux/eal.c
> +++ b/lib/eal/linux/eal.c
> @@ -857,6 +857,64 @@ is_iommu_enabled(void)
> return n > 2;
> }
>
> +static int
> +eal_worker_thread_create(struct internal_config *internal_conf,
> + int lcore_id)
> +{
> + pthread_attr_t attr;
> + size_t stack_size;
> + void *stack_ptr;
> + int ret;
> +
> + if (internal_conf->huge_worker_stack_size == 0)
> + return pthread_create(&lcore_config[lcore_id].thread_id,
> + NULL,
> + eal_thread_loop,
> + (void *)(uintptr_t)lcore_id);
> +
> + /* Allocate NUMA aware stack memory and set pthread attributes */
> + if (pthread_attr_init(&attr) != 0) {
> + rte_eal_init_alert("Cannot init pthread attributes");
> + rte_errno = EFAULT;
> + return -1;
> + }
> + if (internal_conf->huge_worker_stack_size ==
> WORKER_STACK_SIZE_FROM_OS) {
> + if (pthread_attr_getstacksize(&attr, &stack_size) != 0) {
> + rte_errno = EFAULT;
> + return -1;
> + }
> + } else {
> + stack_size = internal_conf->huge_worker_stack_size;
> + }
> + stack_ptr = rte_zmalloc_socket("lcore_stack",
> + stack_size,
> + stack_size,
> + rte_lcore_to_socket_id(lcore_id));
> +
> + if (stack_ptr == NULL) {
> + rte_eal_init_alert("Cannot allocate worker lcore stack
> memory");
> + rte_errno = ENOMEM;
> + return -1;
> + }
> +
> + if (pthread_attr_setstack(&attr, stack_ptr, stack_size) != 0) {
> + rte_eal_init_alert("Cannot set pthread stack attributes");
> + rte_errno = EFAULT;
> + return -1;
> + }
> +
> + ret = pthread_create(&lcore_config[lcore_id].thread_id, &attr,
> + eal_thread_loop,
> + (void *)(uintptr_t)lcore_id);
> +
> + if (pthread_attr_destroy(&attr) != 0) {
> + rte_eal_init_alert("Cannot destroy pthread attributes");
> + rte_errno = EFAULT;
> + return -1;
> + }
> + return ret;
> +}
> +
> /* Launch threads, called at application init(). */ int rte_eal_init(int argc,
> char **argv) @@ -1144,8 +1202,7 @@ rte_eal_init(int argc, char **argv)
> lcore_config[i].state = WAIT;
>
> /* create a thread for each lcore */
> - ret = pthread_create(&lcore_config[i].thread_id, NULL,
> - eal_thread_loop, (void *)(uintptr_t)i);
> + ret = eal_worker_thread_create(internal_conf, i);
> if (ret != 0)
> rte_panic("Cannot create thread\n");
>
> --
> 2.17.1
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