On Wed, Jun 24, 2020 at 08:19:32PM +0300, Alexey Budankov wrote: > > On 17.06.2020 11:35, Alexey Budankov wrote: > > > > Skip fds with zeroed revents field from count and avoid fds moving > > at fdarray__filter() call so fds indices returned by fdarray__add() > > call stay the same and can be used for direct access and processing > > of fd revents status field at entries array of struct fdarray object. > > > > Signed-off-by: Alexey Budankov <[email protected]> > > --- > > tools/lib/api/fd/array.c | 11 +++++------ > > tools/perf/tests/fdarray.c | 20 ++------------------ > > 2 files changed, 7 insertions(+), 24 deletions(-) > > > > diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c > > index 58d44d5eee31..97843a837370 100644 > > --- a/tools/lib/api/fd/array.c > > +++ b/tools/lib/api/fd/array.c > > @@ -93,22 +93,21 @@ int fdarray__filter(struct fdarray *fda, short revents, > > return 0; > > > > for (fd = 0; fd < fda->nr; ++fd) { > > + if (!fda->entries[fd].revents) > > + continue; > > + > > So it looks like this condition also filters out non signaling events fds, > not only > control and others fds, and this should be somehow avoided so such event > related fds > would be counted. Several options have been proposed so far: > > 1) Explicit typing of fds via API extension and filtering based on the types: > a) with separate fdarray__add_stat() call > b) with type arg of existing fdarray__add() call > c) various memory management design is possible > > 2) Playing tricks with fd positions inside entries and assumptions on fdarray > API calls ordering > - looks more like a hack than a designed solution > > 3) Rewrite of fdarray class to allocate separate object for every added fds > - can be replaced with nonscrewing of fds by __filter() > > 4) Distinct between fds types at fdarray__filter() using .revents == 0 > condition > - seems to have corner cases and thus not applicable > > 5) Extension of fdarray__poll(, *arg_ptr, arg_size) with arg of fds array to > atomically poll > on fdarray_add()-ed fds and external arg fds and then external arg fds > processing > > 6) Rewrite of fdarray class on epoll() call basis > - introduces new scalability restrictions for Perf tool
hum, how many fds for polling do you expect in your workloads? jirka
