Re: [igt-dev] [PATCH i-g-t 2/6] igt_core: Split too long log lines when sending to runner with comms

Petri Latvala
2022-11-07T15:14:54Z

On Mon, Nov 07, 2022 at 03:16:18PM +0100, Kamil Konieczny wrote:
> Hi Petri,
>
> On 2022-11-07 at 14:01:47 +0200, Petri Latvala wrote:
> > Especially with file dumps a single log packet could exceed the max
> > size of a UNIX datagram. Split too long log chunks instead.
>
> imho this is needed when you check packet size in other patch,
> it's network layer decision to split or not packets, so on local
> machine no split happens (well, I may be wrong here as I do not
> know much about network communication). The other way around
> would be to collect packet up to sended size.

With SOCK_STREAM, sure, but runnercomms is using SOCK_DGRAM. Datagram
packets are full-or-nothing atomically.

>
> >
> > Signed-off-by: Petri Latvala <petri.latvala@intel.com>
> > Cc: Arkadiusz Hiler <arek@hiler.eu>
> > Cc: Kamil Konieczny <kamil.konieczny@linux.intel.com>
> > ---
> > lib/igt_core.c | 19 ++++++++++++++++++-
> > 1 file changed, 18 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/igt_core.c b/lib/igt_core.c
> > index 3941c528..d4bef161 100644
> > --- a/lib/igt_core.c
> > +++ b/lib/igt_core.c
> > @@ -457,6 +457,23 @@ static void _igt_log_buffer_reset(void)
> > pthread_mutex_unlock(&log_buffer_mutex);
> > }
> >
> > +static void _log_to_runner_split(int stream, const char *str)
> > +{
> > + size_t limit = 4096;
> > + char *buf;
> > +
> > + if (strlen(str) > limit) {
> > + buf = calloc(limit + 1, 1);
> > + strncpy(buf, str, limit);
> > + send_to_runner(runnerpacket_log(stream, buf));
> > + free(buf);
> > +
> > + _log_to_runner_split(stream, str + limit);
> > + } else {
> > + send_to_runner(runnerpacket_log(stream, str));
> > + }
> > +}
> > +
>
> There are many places which calls send_to_runner, maybe it would
> be better to split it there ?

That would complicate send_to_runner a bit too much to my
taste. send_to_runner() is for all packet types, not just for log
packets. It would have to check for packet type log, extract the data
from that packet, and then create new ones...

> Or use _log_to_runner instead of send_to_runner ?
> Btw a while loop would be better than recursive call.

Yeah, you're right. I'll change that to a while loop.

--
Petri Latvala

>
> Kamil
>
> > __attribute__((format(printf, 2, 3)))
> > static void _log_line_fprintf(FILE* stream, const char *format, ...)
> > {
> > @@ -467,7 +484,7 @@ static void _log_line_fprintf(FILE* stream, const char *format, ...)
> >
> > if (runner_connected()) {
> > vasprintf(&str, format, ap);
> > - send_to_runner(runnerpacket_log(fileno(stream), str));
> > + _log_to_runner_split(fileno(stream), str);
> > free(str);
> > } else {
> > vfprintf(stream, format, ap);
> > --
> > 2.30.2
> >