Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Fri, 22 Apr 2016 11:45:30 +0900 Namhyung Kim wrote: > > + pid_list->pid_max = READ_ONCE(pid_max); > > + /* Only truncating will shrink pid_max */ > > + if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max) > > + pid_list->pid_max =

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Fri, 22 Apr 2016 11:45:30 +0900 Namhyung Kim wrote: > > + pid_list->pid_max = READ_ONCE(pid_max); > > + /* Only truncating will shrink pid_max */ > > + if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max) > > + pid_list->pid_max = filtered_pids->pid_max; > > +

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

Hi Steve, On Tue, Apr 19, 2016 at 10:34:23AM -0400, Steven Rostedt wrote: > From: Steven Rostedt > > In order to add the ability to let tasks that are filtered by the events > have their children also be traced on fork (and then not traced on exit), > convert the array into

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

Hi Steve, On Tue, Apr 19, 2016 at 10:34:23AM -0400, Steven Rostedt wrote: > From: Steven Rostedt > > In order to add the ability to let tasks that are filtered by the events > have their children also be traced on fork (and then not traced on exit), > convert the array into a pid bitmask. Most

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 22:59:14 + (UTC) Mathieu Desnoyers wrote: > - On Apr 19, 2016, at 6:49 PM, rostedt rost...@goodmis.org wrote: > > > On Tue, 19 Apr 2016 21:22:21 + (UTC) > > Mathieu Desnoyers wrote: > > > >> It

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 22:59:14 + (UTC) Mathieu Desnoyers wrote: > - On Apr 19, 2016, at 6:49 PM, rostedt rost...@goodmis.org wrote: > > > On Tue, 19 Apr 2016 21:22:21 + (UTC) > > Mathieu Desnoyers wrote: > > > >> It makes sense. Anyway, looking back at my own implementation, I

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 6:49 PM, rostedt rost...@goodmis.org wrote: > On Tue, 19 Apr 2016 21:22:21 + (UTC) > Mathieu Desnoyers wrote: > >> It makes sense. Anyway, looking back at my own implementation, I have >> an array of 64 hlist_head entries (64 * 8 =

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 6:49 PM, rostedt rost...@goodmis.org wrote: > On Tue, 19 Apr 2016 21:22:21 + (UTC) > Mathieu Desnoyers wrote: > >> It makes sense. Anyway, looking back at my own implementation, I have >> an array of 64 hlist_head entries (64 * 8 = 512 bytes), typically >>

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 21:22:21 + (UTC) Mathieu Desnoyers wrote: > It makes sense. Anyway, looking back at my own implementation, I have > an array of 64 hlist_head entries (64 * 8 = 512 bytes), typically > populated by NULL pointers. It's only a factor 8 smaller

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 21:22:21 + (UTC) Mathieu Desnoyers wrote: > It makes sense. Anyway, looking back at my own implementation, I have > an array of 64 hlist_head entries (64 * 8 = 512 bytes), typically > populated by NULL pointers. It's only a factor 8 smaller than the > bitmap, so it's not

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 4:50 PM, rostedt rost...@goodmis.org wrote: > On Tue, 19 Apr 2016 20:17:29 + (UTC) > Mathieu Desnoyers wrote: > > >> Ah indeed, since there is a hard limit to 4194304, that makes the >> worse case bitmap 512k. > > Yep. > >> >> We

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 4:50 PM, rostedt rost...@goodmis.org wrote: > On Tue, 19 Apr 2016 20:17:29 + (UTC) > Mathieu Desnoyers wrote: > > >> Ah indeed, since there is a hard limit to 4194304, that makes the >> worse case bitmap 512k. > > Yep. > >> >> We could argue that given a sparse

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 20:17:29 + (UTC) Mathieu Desnoyers wrote: > Ah indeed, since there is a hard limit to 4194304, that makes the > worse case bitmap 512k. Yep. > > We could argue that given a sparse dataset in the PID table (typical > in our use-cases), a

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 20:17:29 + (UTC) Mathieu Desnoyers wrote: > Ah indeed, since there is a hard limit to 4194304, that makes the > worse case bitmap 512k. Yep. > > We could argue that given a sparse dataset in the PID table (typical > in our use-cases), a small hash table would have

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 3:41 PM, rostedt rost...@goodmis.org wrote: > On Tue, 19 Apr 2016 11:57:32 -0700 > "H. Peter Anvin" wrote: > >> Also, I understand there is one of these bitmaps per ring buffer, and >> the ring buffer is in the tens of megabytes. > > Right, there's

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 3:41 PM, rostedt rost...@goodmis.org wrote: > On Tue, 19 Apr 2016 11:57:32 -0700 > "H. Peter Anvin" wrote: > >> Also, I understand there is one of these bitmaps per ring buffer, and >> the ring buffer is in the tens of megabytes. > > Right, there's only one bitmap per

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 11:57:32 -0700 "H. Peter Anvin" wrote: > Also, I understand there is one of these bitmaps per ring buffer, and > the ring buffer is in the tens of megabytes. Right, there's only one bitmap per tracing instance, which in most cases is just one (I know of

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 11:57:32 -0700 "H. Peter Anvin" wrote: > Also, I understand there is one of these bitmaps per ring buffer, and > the ring buffer is in the tens of megabytes. Right, there's only one bitmap per tracing instance, which in most cases is just one (I know of people who make

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On April 19, 2016 10:19:47 AM PDT, Steven Rostedt wrote: >On Tue, 19 Apr 2016 16:55:28 + (UTC) >Mathieu Desnoyers wrote: > >> - On Apr 19, 2016, at 10:34 AM, rostedt rost...@goodmis.org >wrote: >> >> > From: Steven Rostedt

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On April 19, 2016 10:19:47 AM PDT, Steven Rostedt wrote: >On Tue, 19 Apr 2016 16:55:28 + (UTC) >Mathieu Desnoyers wrote: > >> - On Apr 19, 2016, at 10:34 AM, rostedt rost...@goodmis.org >wrote: >> >> > From: Steven Rostedt >> > >> > In order to add the ability to let tasks that are

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 16:55:28 + (UTC) Mathieu Desnoyers wrote: > - On Apr 19, 2016, at 10:34 AM, rostedt rost...@goodmis.org wrote: > > > From: Steven Rostedt > > > > In order to add the ability to let tasks that are filtered by the

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

On Tue, 19 Apr 2016 16:55:28 + (UTC) Mathieu Desnoyers wrote: > - On Apr 19, 2016, at 10:34 AM, rostedt rost...@goodmis.org wrote: > > > From: Steven Rostedt > > > > In order to add the ability to let tasks that are filtered by the events > > have their children also be traced on fork

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 10:34 AM, rostedt rost...@goodmis.org wrote: > From: Steven Rostedt > > In order to add the ability to let tasks that are filtered by the events > have their children also be traced on fork (and then not traced on exit), > convert the array into

Re: [RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

- On Apr 19, 2016, at 10:34 AM, rostedt rost...@goodmis.org wrote: > From: Steven Rostedt > > In order to add the ability to let tasks that are filtered by the events > have their children also be traced on fork (and then not traced on exit), > convert the array into a pid bitmask. Most

[RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

From: Steven Rostedt In order to add the ability to let tasks that are filtered by the events have their children also be traced on fork (and then not traced on exit), convert the array into a pid bitmask. Most of the time the number of pids is only 32768 pids or a 4k

[RFC][PATCH 2/4] tracing: Use pid bitmap instead of a pid array for set_event_pid

From: Steven Rostedt In order to add the ability to let tasks that are filtered by the events have their children also be traced on fork (and then not traced on exit), convert the array into a pid bitmask. Most of the time the number of pids is only 32768 pids or a 4k bitmask, which is the same