From: Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
To: Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>
Cc: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Namhyung Kim <namhyung-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Arnaldo Carvalho de Melo
<acme-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Jiri Olsa <jolsa-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Masami Hiramatsu
<masami.hiramatsu.pt-FCd8Q96Dh0JBDgjK7y7TUQ@public.gmane.org>,
"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>,
Daniel Borkmann <daniel-FeC+5ew28dpmcu3hnIyYJQ@public.gmane.org>,
Peter Zijlstra
<a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v7 tip 3/8] tracing: allow BPF programs to call bpf_ktime_get_ns()
Date: Thu, 19 Mar 2015 08:38:05 -0700 [thread overview]
Message-ID: <550AED5D.3010700@plumgrid.com> (raw)
In-Reply-To: <20150319111124.38f53061-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
On 3/19/15 8:11 AM, Steven Rostedt wrote:
> On Mon, 16 Mar 2015 14:49:39 -0700
> Alexei Starovoitov <ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org> wrote:
>
>> bpf_ktime_get_ns() is used by programs to compue time delta between events
>
> "compute"
ok :)
>> + [BPF_FUNC_ktime_get_ns] = {
>> + .func = bpf_ktime_get_ns,
>> + .gpl_only = true,
>> + .ret_type = RET_INTEGER,
>
> Hmm, a nanosecond value returned as integer? Is there a way to make
> this a 64 bit return type, or is RET_INTEGER default to 64 bits in BPF
> functions?
RET_INTEGER doesn't mean C 'int' width. It means non-pointer and
non-void value. The return value is always promoted to full
register width which is 64-bit.
next prev parent reply other threads:[~2015-03-19 15:38 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-16 21:49 [PATCH v7 tip 0/8] tracing: attach eBPF programs to kprobes Alexei Starovoitov
2015-03-16 21:49 ` [PATCH v7 tip 1/8] bpf: make internal bpf API independent of CONFIG_BPF_SYSCALL ifdefs Alexei Starovoitov
[not found] ` <1426542584-9406-1-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-03-16 21:49 ` [PATCH v7 tip 2/8] tracing: attach BPF programs to kprobes Alexei Starovoitov
[not found] ` <1426542584-9406-3-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-03-19 15:07 ` Steven Rostedt
[not found] ` <20150319110742.7dc9473d-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
2015-03-19 15:33 ` Alexei Starovoitov
2015-03-20 8:35 ` Masami Hiramatsu
2015-03-16 21:49 ` [PATCH v7 tip 4/8] tracing: allow BPF programs to call bpf_trace_printk() Alexei Starovoitov
[not found] ` <1426542584-9406-5-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-03-19 15:29 ` Steven Rostedt
2015-03-19 15:51 ` Alexei Starovoitov
2015-03-16 21:49 ` [PATCH v7 tip 5/8] samples: bpf: simple non-portable kprobe filter example Alexei Starovoitov
[not found] ` <1426542584-9406-6-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-03-19 15:50 ` Steven Rostedt
2015-03-19 15:53 ` Alexei Starovoitov
2015-03-16 21:49 ` [PATCH v7 tip 3/8] tracing: allow BPF programs to call bpf_ktime_get_ns() Alexei Starovoitov
[not found] ` <1426542584-9406-4-git-send-email-ast-uqk4Ao+rVK5Wk0Htik3J/w@public.gmane.org>
2015-03-19 15:11 ` Steven Rostedt
[not found] ` <20150319111124.38f53061-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
2015-03-19 15:38 ` Alexei Starovoitov [this message]
2015-03-19 15:41 ` Steven Rostedt
2015-03-16 21:49 ` [PATCH v7 tip 6/8] samples: bpf: counting example for kfree_skb and write syscall Alexei Starovoitov
2015-03-16 21:49 ` [PATCH v7 tip 7/8] samples: bpf: IO latency analysis (iosnoop/heatmap) Alexei Starovoitov
2015-03-16 21:49 ` [PATCH v7 tip 8/8] samples: bpf: kmem_alloc/free tracker Alexei Starovoitov
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