From 58e975d014e1e31bd1586be7d2be6d61bd3e3ada Mon Sep 17 00:00:00 2001 From: "Daniel T. Lee" Date: Sun, 15 Jan 2023 16:16:08 +0900 Subject: samples/bpf: replace broken overhead microbenchmark with fib_table_lookup The test_overhead bpf program is designed to compare performance between tracepoint and kprobe. Initially it used task_rename and urandom_read tracepoint. However, commit 14c174633f34 ("random: remove unused tracepoints") removed urandom_read tracepoint, and for this reason the test_overhead got broken. This commit introduces new microbenchmark using fib_table_lookup. This microbenchmark sends UDP packets to localhost in order to invoke fib_table_lookup. In a nutshell: fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); addr.sin_addr.s_addr = inet_addr(DUMMY_IP); addr.sin_port = htons(DUMMY_PORT); for() { sendto(fd, buf, strlen(buf), 0, (struct sockaddr *)&addr, sizeof(addr)); } on 4 cpus in parallel: lookup per sec base (no tracepoints, no kprobes) 381k with kprobe at fib_table_lookup() 325k with tracepoint at fib:fib_table_lookup 330k with raw_tracepoint at fib:fib_table_lookup 365k Fixes: 14c174633f34 ("random: remove unused tracepoints") Signed-off-by: Daniel T. Lee Link: https://lore.kernel.org/r/20230115071613.125791-6-danieltimlee@gmail.com Signed-off-by: Alexei Starovoitov --- samples/bpf/test_overhead_kprobe_kern.c | 2 +- samples/bpf/test_overhead_raw_tp_kern.c | 2 +- samples/bpf/test_overhead_tp_kern.c | 26 +++++++++++++++++++------- samples/bpf/test_overhead_user.c | 28 +++++++++++++++++++--------- 4 files changed, 40 insertions(+), 18 deletions(-) (limited to 'samples') diff --git a/samples/bpf/test_overhead_kprobe_kern.c b/samples/bpf/test_overhead_kprobe_kern.c index 8fdd2c9c56b2b..ba82949338c27 100644 --- a/samples/bpf/test_overhead_kprobe_kern.c +++ b/samples/bpf/test_overhead_kprobe_kern.c @@ -39,7 +39,7 @@ int prog(struct pt_regs *ctx) return 0; } -SEC("kprobe/urandom_read") +SEC("kprobe/fib_table_lookup") int prog2(struct pt_regs *ctx) { return 0; diff --git a/samples/bpf/test_overhead_raw_tp_kern.c b/samples/bpf/test_overhead_raw_tp_kern.c index 8763181a32f37..3e29de0eca98d 100644 --- a/samples/bpf/test_overhead_raw_tp_kern.c +++ b/samples/bpf/test_overhead_raw_tp_kern.c @@ -9,7 +9,7 @@ int prog(struct bpf_raw_tracepoint_args *ctx) return 0; } -SEC("raw_tracepoint/urandom_read") +SEC("raw_tracepoint/fib_table_lookup") int prog2(struct bpf_raw_tracepoint_args *ctx) { return 0; diff --git a/samples/bpf/test_overhead_tp_kern.c b/samples/bpf/test_overhead_tp_kern.c index 80edadacb6925..f170e9b1ea214 100644 --- a/samples/bpf/test_overhead_tp_kern.c +++ b/samples/bpf/test_overhead_tp_kern.c @@ -22,15 +22,27 @@ int prog(struct task_rename *ctx) return 0; } -/* from /sys/kernel/debug/tracing/events/random/urandom_read/format */ -struct urandom_read { +/* from /sys/kernel/debug/tracing/events/fib/fib_table_lookup/format */ +struct fib_table_lookup { __u64 pad; - int got_bits; - int pool_left; - int input_left; + __u32 tb_id; + int err; + int oif; + int iif; + __u8 proto; + __u8 tos; + __u8 scope; + __u8 flags; + __u8 src[4]; + __u8 dst[4]; + __u8 gw4[4]; + __u8 gw6[16]; + __u16 sport; + __u16 dport; + char name[16]; }; -SEC("tracepoint/random/urandom_read") -int prog2(struct urandom_read *ctx) +SEC("tracepoint/fib/fib_table_lookup") +int prog2(struct fib_table_lookup *ctx) { return 0; } diff --git a/samples/bpf/test_overhead_user.c b/samples/bpf/test_overhead_user.c index 88717f8ec6ac5..ce28d30f852eb 100644 --- a/samples/bpf/test_overhead_user.c +++ b/samples/bpf/test_overhead_user.c @@ -11,6 +11,8 @@ #include #include #include +#include +#include #include #include #include @@ -20,6 +22,8 @@ #include #define MAX_CNT 1000000 +#define DUMMY_IP "127.0.0.1" +#define DUMMY_PORT 80 static struct bpf_link *links[2]; static struct bpf_object *obj; @@ -35,8 +39,8 @@ static __u64 time_get_ns(void) static void test_task_rename(int cpu) { - __u64 start_time; char buf[] = "test\n"; + __u64 start_time; int i, fd; fd = open("/proc/self/comm", O_WRONLY|O_TRUNC); @@ -57,26 +61,32 @@ static void test_task_rename(int cpu) close(fd); } -static void test_urandom_read(int cpu) +static void test_fib_table_lookup(int cpu) { + struct sockaddr_in addr; + char buf[] = "test\n"; __u64 start_time; - char buf[4]; int i, fd; - fd = open("/dev/urandom", O_RDONLY); + fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); if (fd < 0) { - printf("couldn't open /dev/urandom\n"); + printf("couldn't open socket\n"); exit(1); } + memset((char *)&addr, 0, sizeof(addr)); + addr.sin_addr.s_addr = inet_addr(DUMMY_IP); + addr.sin_port = htons(DUMMY_PORT); + addr.sin_family = AF_INET; start_time = time_get_ns(); for (i = 0; i < MAX_CNT; i++) { - if (read(fd, buf, sizeof(buf)) < 0) { - printf("failed to read from /dev/urandom: %s\n", strerror(errno)); + if (sendto(fd, buf, strlen(buf), 0, + (struct sockaddr *)&addr, sizeof(addr)) < 0) { + printf("failed to start ping: %s\n", strerror(errno)); close(fd); return; } } - printf("urandom_read:%d: %lld events per sec\n", + printf("fib_table_lookup:%d: %lld events per sec\n", cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time)); close(fd); } @@ -92,7 +102,7 @@ static void loop(int cpu, int flags) if (flags & 1) test_task_rename(cpu); if (flags & 2) - test_urandom_read(cpu); + test_fib_table_lookup(cpu); } static void run_perf_test(int tasks, int flags) -- cgit 1.2.3-korg