[RFC][PATCH 0/4] perf: remove __weak function hw_perf_group_sched_in()

[RFC][PATCH 0/4] perf: remove __weak function hw_perf_group_sched_in()

[Lin Ming]

Hi, all

>From the discussion of thread "[RFC] perf_events: support for uncore
a.k.a. nest units", in order to support multiple hw pmu, Peter suggested
the first thing that needs to be done is get rid of all the __weak
functions (with exception of perf_callchain*, since that really is arch
specific), includes 

hw_perf_group_sched_in
hw_perf_event_init
hw_perf_disable
hw_perf_enable

Peter Zijlstra <peterz@infradead.org> wrote:
> One thing not on that list, which should happen first I guess, is to
> remove hw_perf_group_sched_in(). The idea is to add some sort of
> transactional API to the struct pmu, so that we can delay the
> schedulability check until commit time (and roll back when it fails).
>
> Something as simple as:
>
>  struct pmu {
>    void start_txn(struct pmu *);
>    void commit_txn(struct pmu *);
>
>    ,,,
>  };
>
> and then change group_sched_in() to use this instead of
> hw_perf_group_sched_in(), whose implementations mostly replicate
> group_sched_in() in various buggy ways anyway.
>

This patch series is to remove hw_perf_group_sched_in() first.

patch 1: core, add group scheduling transactional APIs
patch 2: x86, implement group scheduling transactional APIs
patch 3: powerpc, implement group scheduling transactional APIs
patch 4: sparc, implement group scheduling transactional APIs

Thanks for any comment.

Lin Ming

Re: [RFC][PATCH 0/4] perf: remove __weak function hw_perf_group_sched_in()

[Peter Zijlstra]

On Thu, 2010-04-22 at 15:50 +0800, Lin Ming wrote:

> This patch series is to remove hw_perf_group_sched_in() first.
> 
> patch 1: core, add group scheduling transactional APIs
> patch 2: x86, implement group scheduling transactional APIs
> patch 3: powerpc, implement group scheduling transactional APIs
> patch 4: sparc, implement group scheduling transactional APIs
> 
> Thanks for any comment.

Don't RISC architectures deal better with word sized variables than with
u8? I thought it curious you used u8 for the flags thing instead of int
or long, but I'm not quite sure it really matters one way or the other.

Re: [RFC][PATCH 0/4] perf: remove __weak function hw_perf_group_sched_in()

[Lin Ming]

On Thu, 2010-04-22 at 16:29 +0800, Peter Zijlstra wrote:
> On Thu, 2010-04-22 at 15:50 +0800, Lin Ming wrote:
> 
> > This patch series is to remove hw_perf_group_sched_in() first.
> > 
> > patch 1: core, add group scheduling transactional APIs
> > patch 2: x86, implement group scheduling transactional APIs
> > patch 3: powerpc, implement group scheduling transactional APIs
> > patch 4: sparc, implement group scheduling transactional APIs
> > 
> > Thanks for any comment.
> 
> Don't RISC architectures deal better with word sized variables than with
> u8? I thought it curious you used u8 for the flags thing instead of int
> or long, but I'm not quite sure it really matters one way or the other.

Will change it to "unsigned int".

Thanks.