Messages in this thread | | | Date | Fri, 30 Apr 2010 20:49:39 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v2] perf lock: add "info" subcommand for dumping misc information |
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On Sat, Apr 24, 2010 at 07:46:41PM +0900, Hitoshi Mitake wrote: > Hi Frederic, > > I added "info" subcommand to perf lock, > this can be used as dumping metadata like thread or address of lock instances. > "map" was removed because info should do the work of it. > > This will be useful not only for debugging but also for ordinary analyzing. > > I made this patch on perf/core of your tree, could you queue this? > > v2: adding example of usage > % sudo ./perf lock info -t > | Thread ID: comm > | 0: swapper > | 1: init > | 18: migration/5 > | 29: events/2 > | 32: events/5 > | 33: events/6 > ... > > % sudo ./perf lock info -m > | Address of instance: name of class > | 0xffff8800b95adae0: &(&sighand->siglock)->rlock > | 0xffff8800bbb41ae0: &(&sighand->siglock)->rlock > | 0xffff8800bf165ae0: &(&sighand->siglock)->rlock > | 0xffff8800b9576a98: &p->cred_guard_mutex > | 0xffff8800bb890a08: &(&p->alloc_lock)->rlock > | 0xffff8800b9522a08: &(&p->alloc_lock)->rlock > | 0xffff8800bb8aaa08: &(&p->alloc_lock)->rlock > | 0xffff8800bba72a08: &(&p->alloc_lock)->rlock > | 0xffff8800bf18ea08: &(&p->alloc_lock)->rlock > | 0xffff8800b8a0d8a0: &(&ip->i_lock)->mr_lock > | 0xffff88009bf818a0: &(&ip->i_lock)->mr_lock > | 0xffff88004c66b8a0: &(&ip->i_lock)->mr_lock > | 0xffff8800bb6478a0: &(shost->host_lock)->rlock > Signed-off-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Jens Axboe <jens.axboe@oracle.com> > Cc: Jason Baron <jbaron@redhat.com> > Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
I've eventually not queued it because of some various problems, see below:
> --- > tools/perf/builtin-lock.c | 68 +++++++++++++++++++++++++++++++++++++++++++-- > 1 files changed, 65 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c > index ce27675..c54211e 100644 > --- a/tools/perf/builtin-lock.c > +++ b/tools/perf/builtin-lock.c > @@ -778,18 +778,61 @@ static void print_result(void) > } > } > > +static int info_threads; > +static int info_map; > + > +static void rec_dump_threads(struct rb_node *node) > +{ > + struct thread_stat *st; > + struct thread *t; > + > + if (!node) > + return; > + > + if (node->rb_left) > + rec_dump_threads(node->rb_left);
That only walks the left nodes of the rbtree, imagine the following rbtree, W are visited nodes, U are the unvisited:
Root / \ W U / \ / \ W U U U
Better iterate using rb_first() then rb_next() until it is NULL.
> + > + st = container_of(node, struct thread_stat, rb); > + BUG_ON(!st);
You won't ever have !st because container_of computes an address based on a struct type and a contained address inside this struct.
struct thread_stat { struct list_head hash_entry; struct rb_node rb; [...] } ts;
If ts->rb == 1000, ts == 1000 - 16 or something like this.
What matters is the "if (!node)" check you did before.
> + t = perf_session__findnew(session, st->tid); > + BUG_ON(!t); > + > + printf("%10d: %s\n", st->tid, t->comm);
Please don't use printf anymore (I did the same mistakes lately), now that are using a TUI and we might use a GUI one day, we can't assume anymore we are dealing with a normal stdout.
So better use pr_debug, pr_err, pr_warning, etc...
> + > + if (node->rb_right) > + rec_dump_threads(node->rb_right); > +} > + > +static void dump_threads(void) > +{ > + printf("%10s: comm\n", "Thread ID");
Same here and below.
> + rec_dump_threads(thread_stats.rb_node); > +} > + > static void dump_map(void) > { > unsigned int i; > struct lock_stat *st; > > + printf("Address of instance: name of class\n"); > for (i = 0; i < LOCKHASH_SIZE; i++) { > list_for_each_entry(st, &lockhash_table[i], hash_entry) { > - printf("%p: %s\n", st->addr, st->name); > + printf(" %p: %s\n", st->addr, st->name); > } > } > } > > +static void dump_info(void) > +{ > + /* ugly... */ > + if (info_threads) > + dump_threads();
No it's not ugly, it's ok, we do this everywhere in perf tools :)
Thanks.
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