Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-23 Thread David Miller
From: Alexei Starovoitov Date: Fri, 19 Jun 2015 17:53:57 -0700 > On 6/19/15 7:00 AM, Daniel Wagner wrote: >> BPF offers another way to generate latency histograms. We attach >> kprobes at trace_preempt_off and trace_preempt_on and calculate the >> time it takes to from seeing the off/on

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-23 Thread David Miller
From: Alexei Starovoitov a...@plumgrid.com Date: Fri, 19 Jun 2015 17:53:57 -0700 On 6/19/15 7:00 AM, Daniel Wagner wrote: BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-22 Thread Daniel Wagner
On 06/20/2015 10:14 AM, Daniel Borkmann wrote: > I think it would be useful to perhaps have two options: > > 1) User specifies a specific CPU and gets one such an output above. Good point. Will do. > 2) Summary view, i.e. to have the samples of each CPU for comparison >next to each other in

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-22 Thread Daniel Wagner
On 06/20/2015 10:14 AM, Daniel Borkmann wrote: I think it would be useful to perhaps have two options: 1) User specifies a specific CPU and gets one such an output above. Good point. Will do. 2) Summary view, i.e. to have the samples of each CPU for comparison next to each other in

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-20 Thread Daniel Borkmann
On 06/19/2015 04:00 PM, Daniel Wagner wrote: BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the off/on transition. The first array is used to store the start time stamp. The key is

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-20 Thread Daniel Borkmann
On 06/19/2015 04:00 PM, Daniel Wagner wrote: BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the off/on transition. The first array is used to store the start time stamp. The key is

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-19 Thread Alexei Starovoitov
On 6/19/15 7:00 AM, Daniel Wagner wrote: BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the off/on transition. ... Signed-off-by: Daniel Wagner ... With the rebase on net-next

[PATCH v2] bpf: BPF based latency tracing

2015-06-19 Thread Daniel Wagner
BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the off/on transition. The first array is used to store the start time stamp. The key is the CPU id. The second array stores the

Re: [PATCH v2] bpf: BPF based latency tracing

2015-06-19 Thread Alexei Starovoitov
On 6/19/15 7:00 AM, Daniel Wagner wrote: BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the off/on transition. ... Signed-off-by: Daniel Wagner daniel.wag...@bmw-carit.de ...

[PATCH v2] bpf: BPF based latency tracing

2015-06-19 Thread Daniel Wagner
BPF offers another way to generate latency histograms. We attach kprobes at trace_preempt_off and trace_preempt_on and calculate the time it takes to from seeing the off/on transition. The first array is used to store the start time stamp. The key is the CPU id. The second array stores the