[dpdk-dev] [PKTGEN] fixing weird termio issues that complicate debugging

[Wiles, Keith]

On 1/20/16, 10:26 AM, "dev on behalf of Wiles, Keith" <dev-bounces at dpdk.org on behalf of keith.wiles at intel.com> wrote:

>On 1/20/16, 12:32 AM, "dev on behalf of Matthew Hall" <dev-bounces at dpdk.org on behalf of mhall at mhcomputing.net> wrote:
>
>>Hello,

Please try modifying pktgen-main.c:main() at the top of the function to this:

    wr_scrn_setw(1);		/* Reset the window size, from possible crash run. */
    wr_scrn_pos(100, 1);	/* Move the cursor to the bottom of the screen again */

    printf("\n%s %s\n", wr_copyright_msg(), wr_powered_by()); fflush(stdout);

    /* call before the rte_eal_init() */
    (void)rte_set_application_usage_hook(pktgen_usage);

Maybe this will fix up most of your issues with DPDK output. I normally set the log-level to 7 to remove most of the DPDK messages.


>>
>>Since the pktgen code is reindented I am finding time to read through it 
>>and experiment and see if I can get it working.
>>
>>I have issues with the init process of pktgen. It is difficult to debug 
>>it because the init code does a lot of very scary stuff to the terminal 
>>control / TTY device at inconvenient times in an inconvenient order, and 
>>in the process damages the debug output and damages the screen of your 
>>GDB without doing weird things to run GDB on a different TTY.
>>
>>Of course I am willing to contribute patches and not just complain, but 
>>first I need some help to follow what is going on.
>>
>>Here is the problematic call-flow with some explanation what went wrong 
>>trying it on some community machines outside of its original environment:
>>
>>1) it calls printf("\n%s %s\n", wr_copyright_msg(), wr_powered_by()); 
>>which dumps tons of weird boilerplate of licenses, copyrights, code 
>>creator, etc.
>>
>>It is open source and everybody that matters already knows who coded it, 
>>so is this stuff really that important? This gets in the way when you 
>>are trying to work on it and I just have to comment it out.
>
>One problem is a number of people wanted to steal the code and use in a paid application, so the copyright is some what a requirement. As you may know I do a lot of debugging on Pktgen and I feel they are a nuisance. I can try to see if we can clean up these messages, but do not hold your breath on getting them to be removed. 
>>
>>2) it calls wr_scrn_setw and tinkers with the windows size very early in 
>>the init which can make your terminal weird
>>
>>3) it calls rte_eal_init which produces a lot of nice debug output, 
>>which is fine
>
>IMO most of the information from DPDK is not very useful as why do I need to see every lcore line, plus a lot of more useless information. Most of the information could be reduced a couple of lines or only report issues not just a bunch of useless information.
>>
>>4) it calls pktgen_init_screen, which calls wr_scrn_init, which calls 
>>wr_scrn_erase which destroys the valuable debug output just created in 
>>(c) which is a bad thing
>
>The screen init should be scrolling the information off the screen to preserve that info, unless it was changed by mistake.
>>
>>5) it calls wr_print_copyright and dumps more boilerplate I am not sure 
>>is needed
>>
>>6) it logs some helpful messages about the port / descriptor settings 
>>which is fine
>>
>>7) it calls the pktgen_config_ports function which can crash in ways you 
>>need the destroyed debug output to fix.
>>
>>For example in my case that function crashes here:
>>
>>         if (pktgen.nb_ports == 0)
>>                 pktgen_log_panic("*** Did not find any ports to use ***");
>>
>>8) Later it makes a logo and a splash screen (wr_log, wr_splash_screen). 
>>Is this stuff really needed? This is a ton of output for just starting 
>>up some test program.
>>
>>To fix this debug problem I propose some changes which I am happy to 
>>help develop:
>>
>>1) decide what of this output we really need here and greatly simplify 
>>how much gets printed out
>>
>>2) move wr_scrn_setw right before pktgen_init_screen and after 
>>rte_eal_init to prevent damaging that output
>>
>>3) consider how wr_scrn_init is called in pktgen_init_screen, because it 
>>calls wr_scrn_erase which damages output
>
>Again it could be scrolling that information off the screen, just need a large screen scroll buffer.
>>
>>4) I think that pktgen_config_ports should be called before all this 
>>weird screen init stuff, so that if it fails you can actually see what 
>>happened there.
>>
>>One other random topic... on the long lines of code it looks like there 
>>are some gigantic tab-indents pushing things off to the right still. One 
>>example, maybe there are others or another setting which is needed to 
>>fix all of these:
>
>Please use tab stop of 4 instead of 8. IMO tab stop of 8 is so 1970’s and we should not need tab stop of 8 as any system today will work. :-)
>>
>>                 info->seq_pkt = (pkt_seq_t *)rte_zmalloc_socket(buff, 
>>(sizeof(pkt_seq_t) * NUM_TOTAL_PKTS),
>> 
>>                                          RTE_CACHE_LINE_SIZE, 
>>rte_socket_id());
>>
>>Thoughts?
>>Matthew Hall
>
>Improvement to Pktgen is always welcome and the copyright info is going to be a bit hard to remove as that was one of the requirements when I open sourced the code. I understand it maybe a bit of output. I do not think it is really a user issue causing users to stop using it as startup is only down once, in my case I may start Pktgen a few times a day for development and it does not seem to slow me down much. :-)
>>
>
>
>Regards,
>Keith
>
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Regards,
Keith