Hi Peter,
On 2015/11/25 17:27, Peter Zijlstra wrote:
On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
In our patch, we create and maintain a user space ring buffer to store
perf's tracing info, instead of directly writing to perf.data file as
before. In snapshot mode, only a SIGUSR
* Ingo Molnar wrote:
> So if an overwrite-mode background tracing session is running, you don't even
> have
> to signal it to capture the ring-buffer: just open the ring-buffer fd in
> procfs,
> under /proc/XYZ/perf/ring-buffers/5.trace or so, and dump its current
> contents,
> assuming th
* Ingo Molnar wrote:
>
> * Ingo Molnar wrote:
>
> > > But yes, we can do that userspace ring buffer when we really need it. At
> > > very first we can start working on perf side and assume overwrite mode is
> > > ready.
> >
> > I don't think Peter asked for much: pick up the patch he has a
* Ingo Molnar wrote:
> > But yes, we can do that userspace ring buffer when we really need it. At
> > very
> > first we can start working on perf side and assume overwrite mode is ready.
>
> I don't think Peter asked for much: pick up the patch he has already written
> and
> use it, to have
On 2015/11/26 17:19, Ingo Molnar wrote:
* Wangnan (F) wrote:
On 2015/11/25 20:20, Peter Zijlstra wrote:
On Wed, Nov 25, 2015 at 05:44:00PM +0800, Wangnan (F) wrote:
On 2015/11/25 17:27, Peter Zijlstra wrote:
On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
In our patch, we
* Wangnan (F) wrote:
>
>
> On 2015/11/25 20:20, Peter Zijlstra wrote:
> >On Wed, Nov 25, 2015 at 05:44:00PM +0800, Wangnan (F) wrote:
> >>
> >>On 2015/11/25 17:27, Peter Zijlstra wrote:
> >>>On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
> In our patch, we create and maintai
On 2015/11/25 20:20, Peter Zijlstra wrote:
On Wed, Nov 25, 2015 at 05:44:00PM +0800, Wangnan (F) wrote:
On 2015/11/25 17:27, Peter Zijlstra wrote:
On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
In our patch, we create and maintain a user space ring buffer to store
perf's trac
On 2015/11/24 22:30, Arnaldo Carvalho de Melo wrote:
> Looks like an interesting feature, if for no other reason, to match what
> we have for aux area tracing.
>
> But perhaps having an event in the stream itself that would signal when
> to dump the snapshot would be a better approach?
>
> One t
On Wed, Nov 25, 2015 at 05:44:00PM +0800, Wangnan (F) wrote:
>
>
> On 2015/11/25 17:27, Peter Zijlstra wrote:
> >On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
> >>In our patch, we create and maintain a user space ring buffer to store
> >>perf's tracing info, instead of directly wr
On 2015/11/25 17:27, Peter Zijlstra wrote:
On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
In our patch, we create and maintain a user space ring buffer to store
perf's tracing info, instead of directly writing to perf.data file as
before. In snapshot mode, only a SIGUSR2 signal
On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote:
> In our patch, we create and maintain a user space ring buffer to store
> perf's tracing info, instead of directly writing to perf.data file as
> before. In snapshot mode, only a SIGUSR2 signal can trigger perf to dump
> the tracing inf
On 25/11/15 10:43, Wangnan (F) wrote:
>
>
> On 2015/11/25 16:27, Adrian Hunter wrote:
>> On 25/11/15 09:47, Wangnan (F) wrote:
>>>
>>> On 2015/11/25 15:22, Adrian Hunter wrote:
On 25/11/15 05:50, Wangnan (F) wrote:
> On 2015/11/24 23:20, Arnaldo Carvalho de Melo wrote:
>> Em Tue, Nov
On 2015/11/25 16:27, Adrian Hunter wrote:
On 25/11/15 09:47, Wangnan (F) wrote:
On 2015/11/25 15:22, Adrian Hunter wrote:
On 25/11/15 05:50, Wangnan (F) wrote:
On 2015/11/24 23:20, Arnaldo Carvalho de Melo wrote:
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
On 11/24/15
On 25/11/15 09:47, Wangnan (F) wrote:
>
>
> On 2015/11/25 15:22, Adrian Hunter wrote:
>> On 25/11/15 05:50, Wangnan (F) wrote:
>>>
>>> On 2015/11/24 23:20, Arnaldo Carvalho de Melo wrote:
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
> On 11/24/15 7:00 AM, Yunlong Song
On 2015/11/24 23:06, David Ahern wrote:
>
> So you are basically ignoring all samples until SIGUSR2 is received. That
> means the resulting data file will have limited history of task events for
> example. And for other events the quantity is random as to when the mmaps
> were last scanned.
>
On 2015/11/25 15:22, Adrian Hunter wrote:
On 25/11/15 05:50, Wangnan (F) wrote:
On 2015/11/24 23:20, Arnaldo Carvalho de Melo wrote:
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
On 11/24/15 7:00 AM, Yunlong Song wrote:
+static int record__write(struct record *rec, void *
On 25/11/15 05:50, Wangnan (F) wrote:
>
>
> On 2015/11/24 23:20, Arnaldo Carvalho de Melo wrote:
>> Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
>>> On 11/24/15 7:00 AM, Yunlong Song wrote:
+static int record__write(struct record *rec, void *bf, size_t size)
+{
+
On 11/24/15 8:50 PM, Wangnan (F) wrote:
Actually we are discussing about this problem.
For such tracking events (PERF_RECORD_FORK...), we have dummy event so
it is possible for us to receive tracking events from a separated
channel, therefore we don't have to parse every events to pick those
eve
On 2015/11/24 23:20, Arnaldo Carvalho de Melo wrote:
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
On 11/24/15 7:00 AM, Yunlong Song wrote:
+static int record__write(struct record *rec, void *bf, size_t size)
+{
+ if (rec->memory.size && memory_enabled) {
+
On 11/24/15 8:40 AM, Arnaldo Carvalho de Melo wrote:
perf-record without his patch? yes, but with his patch it does:
__cmd_record()
for (;;)
record__mmap_read_all()
record__write()
perf_memory__write()
event
Em Tue, Nov 24, 2015 at 08:24:07AM -0700, David Ahern escreveu:
> On 11/24/15 8:20 AM, Arnaldo Carvalho de Melo wrote:
> >Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
> >>On 11/24/15 7:00 AM, Yunlong Song wrote:
> >>>+static int record__write(struct record *rec, void *bf, size_t
On 11/24/15 8:20 AM, Arnaldo Carvalho de Melo wrote:
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
On 11/24/15 7:00 AM, Yunlong Song wrote:
+static int record__write(struct record *rec, void *bf, size_t size)
+{
+ if (rec->memory.size && memory_enabled) {
+
Em Tue, Nov 24, 2015 at 08:06:41AM -0700, David Ahern escreveu:
> On 11/24/15 7:00 AM, Yunlong Song wrote:
> >+static int record__write(struct record *rec, void *bf, size_t size)
> >+{
> >+if (rec->memory.size && memory_enabled) {
> >+if (perf_memory__write(&rec->memory, bf, size) <
On 11/24/15 7:00 AM, Yunlong Song wrote:
+static int record__write(struct record *rec, void *bf, size_t size)
+{
+ if (rec->memory.size && memory_enabled) {
+ if (perf_memory__write(&rec->memory, bf, size) < 0) {
+ pr_err("failed to write memory data, err
Em Tue, Nov 24, 2015 at 10:00:32PM +0800, Yunlong Song escreveu:
> For aux area tracing, there is already a snapshot mode support for
> intel-pt and intel-bts events. Similarly, this patch adds a snapshot
> mode for perf's regular events. A user space ring buffer is allocated to
> handle the tracin
For aux area tracing, there is already a snapshot mode support for
intel-pt and intel-bts events. Similarly, this patch adds a snapshot
mode for perf's regular events. A user space ring buffer is allocated to
handle the tracing data from the kernel space ring buffer, and the
tracing data will only
This idea is issued and motivated from:
https://lwn.net/Articles/650499/
After the first RFC is sent:
http://lkml.iu.edu/hypermail/linux/kernel/1509.2/04347.html
Both David Ahern and Borislav Petkov have replied to that RFC:
http://lkml.iu.edu/hypermail/linux/kernel/1509.2/04350.html
http://lkml.
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