From: Alexei Starovoitov <ast@plumgrid.com>
To: Kaixu Xia <xiakaixu@huawei.com>,
davem@davemloft.net, acme@kernel.org, mingo@redhat.com,
a.p.zijlstra@chello.nl, masami.hiramatsu.pt@hitachi.com,
jolsa@kernel.org
Cc: wangnan0@huawei.com, linux-kernel@vger.kernel.org,
pi3orama@163.com, hekuang@huawei.com
Subject: Re: [PATCH v2 5/5] samples/bpf: example of get selected PMU counter value
Date: Wed, 22 Jul 2015 18:16:08 -0700 [thread overview]
Message-ID: <55B04058.4090006@plumgrid.com> (raw)
In-Reply-To: <1437552572-84748-6-git-send-email-xiakaixu@huawei.com>
On 7/22/15 1:09 AM, Kaixu Xia wrote:
> +SEC("kprobe/sys_write")
> +int bpf_prog1(struct pt_regs *ctx)
> +{
> + u64 count;
> + u32 key = bpf_get_smp_processor_id();
> + char fmt[] = "bpf count: CPU-%d %llu\n";
> +
> + count = bpf_perf_event_read(&my_map, &key);
> + bpf_trace_printk(fmt, sizeof(fmt), key, count);
> +
> + return 0;
> +}
overall the whole thing looks much better, but since you can print
anything, print some sensible string here instead of 'bpf count'.
Thanks!
next prev parent reply other threads:[~2015-07-23 1:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-22 8:09 [PATCH v2 0/5] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Kaixu Xia
2015-07-22 8:09 ` [PATCH v2 1/5] bpf: Add new bpf map type to store the pointer to struct perf_event Kaixu Xia
2015-07-23 0:48 ` Alexei Starovoitov
2015-07-23 1:08 ` Wangnan (F)
2015-07-23 1:39 ` Alexei Starovoitov
2015-07-22 8:09 ` [PATCH v2 2/5] bpf: Add function map->ops->map_traverse_elem() to traverse map elems Kaixu Xia
2015-07-23 1:00 ` Alexei Starovoitov
2015-07-22 8:09 ` [PATCH v2 3/5] bpf: Save the pointer to struct perf_event to map Kaixu Xia
2015-07-23 1:08 ` Alexei Starovoitov
2015-07-22 8:09 ` [PATCH v2 4/5] bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter Kaixu Xia
2015-07-23 1:14 ` Alexei Starovoitov
2015-07-23 2:12 ` xiakaixu
2015-07-23 2:22 ` Alexei Starovoitov
2015-07-23 2:39 ` xiakaixu
2015-07-22 8:09 ` [PATCH v2 5/5] samples/bpf: example of get selected PMU counter value Kaixu Xia
2015-07-23 1:16 ` Alexei Starovoitov [this message]
2015-07-23 23:33 ` [PATCH v2 0/5] bpf: Introduce the new ability of eBPF programs to access hardware PMU counter Daniel Borkmann
2015-07-25 2:14 ` xiakaixu
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