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b50ba626cc
The RESIZE_ARRAY() macro assumes the presence of an in-scope "skel" variable. This is bad practice and can cause issues in other macros that use it. Let's update it to explicitly take a skel argument. Signed-off-by: David Vernet <void@manifault.com>
136 lines
3.8 KiB
C
136 lines
3.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
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* Copyright (c) 2022 Tejun Heo <tj@kernel.org>
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* Copyright (c) 2022 David Vernet <dvernet@meta.com>
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*/
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#define _GNU_SOURCE
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#include <sched.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <inttypes.h>
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#include <signal.h>
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#include <libgen.h>
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#include <bpf/bpf.h>
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#include <scx/common.h>
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#include "scx_central.bpf.skel.h"
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const char help_fmt[] =
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"A central FIFO sched_ext scheduler.\n"
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"\n"
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"See the top-level comment in .bpf.c for more details.\n"
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"\n"
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"Usage: %s [-s SLICE_US] [-c CPU]\n"
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"\n"
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" -s SLICE_US Override slice duration\n"
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" -c CPU Override the central CPU (default: 0)\n"
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" -v Print libbpf debug messages\n"
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" -h Display this help and exit\n";
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static bool verbose;
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static volatile int exit_req;
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static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
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{
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if (level == LIBBPF_DEBUG && !verbose)
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return 0;
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return vfprintf(stderr, format, args);
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}
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static void sigint_handler(int dummy)
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{
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exit_req = 1;
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}
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int main(int argc, char **argv)
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{
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struct scx_central *skel;
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struct bpf_link *link;
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__u64 seq = 0, ecode;
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__s32 opt;
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cpu_set_t *cpuset;
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libbpf_set_print(libbpf_print_fn);
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signal(SIGINT, sigint_handler);
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signal(SIGTERM, sigint_handler);
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restart:
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skel = SCX_OPS_OPEN(central_ops, scx_central);
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skel->rodata->central_cpu = 0;
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skel->rodata->nr_cpu_ids = libbpf_num_possible_cpus();
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while ((opt = getopt(argc, argv, "s:c:pvh")) != -1) {
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switch (opt) {
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case 's':
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skel->rodata->slice_ns = strtoull(optarg, NULL, 0) * 1000;
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break;
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case 'c':
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skel->rodata->central_cpu = strtoul(optarg, NULL, 0);
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break;
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case 'v':
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verbose = true;
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break;
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default:
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fprintf(stderr, help_fmt, basename(argv[0]));
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return opt != 'h';
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}
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}
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/* Resize arrays so their element count is equal to cpu count. */
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RESIZE_ARRAY(skel, data, cpu_gimme_task, skel->rodata->nr_cpu_ids);
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RESIZE_ARRAY(skel, data, cpu_started_at, skel->rodata->nr_cpu_ids);
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SCX_OPS_LOAD(skel, central_ops, scx_central, uei);
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/*
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* Affinitize the loading thread to the central CPU, as:
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* - That's where the BPF timer is first invoked in the BPF program.
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* - We probably don't want this user space component to take up a core
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* from a task that would benefit from avoiding preemption on one of
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* the tickless cores.
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*
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* Until BPF supports pinning the timer, it's not guaranteed that it
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* will always be invoked on the central CPU. In practice, this
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* suffices the majority of the time.
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*/
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cpuset = CPU_ALLOC(skel->rodata->nr_cpu_ids);
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SCX_BUG_ON(!cpuset, "Failed to allocate cpuset");
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CPU_ZERO(cpuset);
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CPU_SET(skel->rodata->central_cpu, cpuset);
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SCX_BUG_ON(sched_setaffinity(0, sizeof(cpuset), cpuset),
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"Failed to affinitize to central CPU %d (max %d)",
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skel->rodata->central_cpu, skel->rodata->nr_cpu_ids - 1);
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CPU_FREE(cpuset);
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link = SCX_OPS_ATTACH(skel, central_ops, scx_central);
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if (!skel->data->timer_pinned)
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printf("WARNING : BPF_F_TIMER_CPU_PIN not available, timer not pinned to central\n");
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while (!exit_req && !UEI_EXITED(skel, uei)) {
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printf("[SEQ %llu]\n", seq++);
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printf("total :%10" PRIu64 " local:%10" PRIu64 " queued:%10" PRIu64 " lost:%10" PRIu64 "\n",
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skel->bss->nr_total,
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skel->bss->nr_locals,
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skel->bss->nr_queued,
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skel->bss->nr_lost_pids);
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printf("timer :%10" PRIu64 " dispatch:%10" PRIu64 " mismatch:%10" PRIu64 " retry:%10" PRIu64 "\n",
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skel->bss->nr_timers,
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skel->bss->nr_dispatches,
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skel->bss->nr_mismatches,
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skel->bss->nr_retries);
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printf("overflow:%10" PRIu64 "\n",
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skel->bss->nr_overflows);
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fflush(stdout);
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sleep(1);
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}
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bpf_link__destroy(link);
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ecode = UEI_REPORT(skel, uei);
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scx_central__destroy(skel);
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if (UEI_ECODE_RESTART(ecode))
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goto restart;
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return 0;
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}
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