Subject: Re: [PATCH v2 5/5] samples/bpf: example of get selected PMU counter
 value
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
References: <1437552572-84748-1-git-send-email-xiakaixu@huawei.com>
 <1437552572-84748-6-git-send-email-xiakaixu@huawei.com>
Cc: wangnan0@huawei.com, linux-kernel@vger.kernel.org, pi3orama@163.com,
        hekuang@huawei.com
From: Alexei Starovoitov <ast@plumgrid.com>
Message-ID: <55B04058.4090006@plumgrid.com>
Date: Wed, 22 Jul 2015 18:16:08 -0700
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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!

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