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Date: Mon, 25 Jun 2018 14:25:02 +0200
From: Toke Høiland-Jørgensen <toke@...e.dk>
To: netdev@...r.kernel.org
Subject: [PATCH RESEND bpf-next v6 1/2] trace_helpers.c: Add helpers to poll
multiple perf FDs for events
Add two new helper functions to trace_helpers that supports polling
multiple perf file descriptors for events. These are used to the XDP
perf_event_output example, which needs to work with one perf fd per CPU.
Reviewed-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@...e.dk>
---
tools/testing/selftests/bpf/trace_helpers.c | 48 ++++++++++++++++++++++++++-
tools/testing/selftests/bpf/trace_helpers.h | 4 ++
2 files changed, 50 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 3868dcb63420..cabe2a3a3b30 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -88,7 +88,7 @@ static int page_size;
static int page_cnt = 8;
static struct perf_event_mmap_page *header;
-int perf_event_mmap(int fd)
+int perf_event_mmap_header(int fd, struct perf_event_mmap_page **header)
{
void *base;
int mmap_size;
@@ -102,10 +102,15 @@ int perf_event_mmap(int fd)
return -1;
}
- header = base;
+ *header = base;
return 0;
}
+int perf_event_mmap(int fd)
+{
+ return perf_event_mmap_header(fd, &header);
+}
+
static int perf_event_poll(int fd)
{
struct pollfd pfd = { .fd = fd, .events = POLLIN };
@@ -163,3 +168,42 @@ int perf_event_poller(int fd, perf_event_print_fn output_fn)
return ret;
}
+
+int perf_event_poller_multi(int *fds, struct perf_event_mmap_page **headers,
+ int num_fds, perf_event_print_fn output_fn)
+{
+ enum bpf_perf_event_ret ret;
+ struct pollfd *pfds;
+ void *buf = NULL;
+ size_t len = 0;
+ int i;
+
+ pfds = calloc(num_fds, sizeof(*pfds));
+ if (!pfds)
+ return LIBBPF_PERF_EVENT_ERROR;
+
+ for (i = 0; i < num_fds; i++) {
+ pfds[i].fd = fds[i];
+ pfds[i].events = POLLIN;
+ }
+
+ for (;;) {
+ poll(pfds, num_fds, 1000);
+ for (i = 0; i < num_fds; i++) {
+ if (!pfds[i].revents)
+ continue;
+
+ ret = bpf_perf_event_read_simple(headers[i],
+ page_cnt * page_size,
+ page_size, &buf, &len,
+ bpf_perf_event_print,
+ output_fn);
+ if (ret != LIBBPF_PERF_EVENT_CONT)
+ break;
+ }
+ }
+ free(buf);
+ free(pfds);
+
+ return ret;
+}
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 3b4bcf7f5084..18924f23db1b 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -3,6 +3,7 @@
#define __TRACE_HELPER_H
#include <libbpf.h>
+#include <linux/perf_event.h>
struct ksym {
long addr;
@@ -16,6 +17,9 @@ long ksym_get_addr(const char *name);
typedef enum bpf_perf_event_ret (*perf_event_print_fn)(void *data, int size);
int perf_event_mmap(int fd);
+int perf_event_mmap_header(int fd, struct perf_event_mmap_page **header);
/* return LIBBPF_PERF_EVENT_DONE or LIBBPF_PERF_EVENT_ERROR */
int perf_event_poller(int fd, perf_event_print_fn output_fn);
+int perf_event_poller_multi(int *fds, struct perf_event_mmap_page **headers,
+ int num_fds, perf_event_print_fn output_fn);
#endif
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