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From:   Song Liu <songliubraving@fb.com>
To:     David Ahern <dsahern@gmail.com>
CC:     Peter Zijlstra <peterz@infradead.org>,
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Subject: Re: [RFC perf,bpf 1/5] perf, bpf: Introduce PERF_RECORD_BPF_EVENT
Thread-Topic: [RFC perf,bpf 1/5] perf, bpf: Introduce PERF_RECORD_BPF_EVENT
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Date:   Thu, 8 Nov 2018 18:49:19 +0000
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Hi David,

> On Nov 8, 2018, at 10:26 AM, David Ahern <dsahern@gmail.com> wrote:
>=20
> On 11/8/18 11:04 AM, Song Liu wrote:
>> On the other hand, processing BPF load/unload events synchronously shoul=
d
>> not introduce too much overhead for meaningful use cases. If many BPF pr=
ogs
>> are being loaded/unloaded within short period of time, it is not the ste=
ady
>> state that profiling works care about.=20
>=20
> but, profiling is not the only use case, and perf-record is common with
> those other use cases.
>=20
> I think that answers why your RFC set does not fork a thread for the bpf
> events. You are focused on profiling and for already loaded programs or
> for a small number of programs loaded by a specific workload started by
> perf.

We sure can fork a thread for the BPF event. But I guess that's not Peter's
main concern here...

Could you please point me to more information about the use cases you worry=
=20
about? I am more than happy to optimize the logic for those use cases.=20

Thanks,
Song