Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-08-18 Thread Daniel Xu
Hi Maciej, On Tue Aug 18, 2020 at 2:19 PM PDT, Maciej Żenczykowski wrote: > On Tue, Aug 18, 2020 at 2:11 PM Daniel Xu wrote: > > > > On Mon Jul 27, 2020 at 10:01 PM PDT, Andrii Nakryiko wrote: > > > On Mon, Jul 27, 2020 at 4:35 PM wrote: > > > > > > > > From: Ashkan Nikravesh > > > > > > > > Th

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-08-18 Thread Daniel Xu
On Mon Jul 27, 2020 at 10:01 PM PDT, Andrii Nakryiko wrote: > On Mon, Jul 27, 2020 at 4:35 PM wrote: > > > > From: Ashkan Nikravesh > > > > The existing bpf helper functions to get timestamp return the time > > elapsed since system boot. This timestamp is not particularly useful > > where epoch t

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-29 Thread David Ahern
On 7/28/20 11:15 PM, Andrii Nakryiko wrote: > On Tue, Jul 28, 2020 at 1:57 PM David Ahern wrote: >> >> On 7/28/20 12:28 PM, Andrii Nakryiko wrote: >>> In some, yes, which also means that in some other they can't. So I'm >>> still worried about misuses of REALCLOCK, within (internal daemons >>> wit

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-28 Thread Andrii Nakryiko
On Tue, Jul 28, 2020 at 1:57 PM David Ahern wrote: > > On 7/28/20 12:28 PM, Andrii Nakryiko wrote: > > In some, yes, which also means that in some other they can't. So I'm > > still worried about misuses of REALCLOCK, within (internal daemons > > within the company) our outside (BCC tools and alik

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-28 Thread Andrii Nakryiko
Starovoitov ; Daniel Borkmann ; > Martin Lau ; Nikravesh, Ashkan > Subject: Re: [PATCH] bpf: Add bpf_ktime_get_real_ns > > On Tue, Jul 28, 2020 at 10:57 AM Maciej Żenczykowski wrote: > > > > On Mon, Jul 27, 2020 at 10:01 PM Andrii Nakryiko > > wrote: > >> &g

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-28 Thread David Ahern
On 7/28/20 12:28 PM, Andrii Nakryiko wrote: > In some, yes, which also means that in some other they can't. So I'm > still worried about misuses of REALCLOCK, within (internal daemons > within the company) our outside (BCC tools and alike) of data centers. > Especially if people will start using it

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-28 Thread Andrii Nakryiko
On Tue, Jul 28, 2020 at 10:57 AM Maciej Żenczykowski wrote: > > On Mon, Jul 27, 2020 at 10:01 PM Andrii Nakryiko > wrote: >> >> On Mon, Jul 27, 2020 at 4:35 PM wrote: >> > >> > From: Ashkan Nikravesh >> > >> > The existing bpf helper functions to get timestamp return the time >> > elapsed sinc

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-27 Thread Andrii Nakryiko
On Mon, Jul 27, 2020 at 4:35 PM wrote: > > From: Ashkan Nikravesh > > The existing bpf helper functions to get timestamp return the time > elapsed since system boot. This timestamp is not particularly useful > where epoch timestamp is required or more than one server is involved > and time sync i

Re: [PATCH] bpf: Add bpf_ktime_get_real_ns

2020-07-27 Thread Song Liu
On Mon, Jul 27, 2020 at 4:35 PM wrote: > > From: Ashkan Nikravesh > > The existing bpf helper functions to get timestamp return the time > elapsed since system boot. This timestamp is not particularly useful > where epoch timestamp is required or more than one server is involved > and time sync i