Steve Langasek [2015-10-22 18:11 -0000]:
> > * If we really want to dump, we could investigate into sendfile. I'm not
> > * entirely sure that it works with data coming in via stdin, but it's
> > * worth a try as we would avoid the kernel -> userspace copy.
>
> This is an interesting suggestion. It would imply requiring a second
> post-processing stage, to combine this file with the rest of the crash
> report in proper (compressed, base64-encoded) format;
How would that help? In any case you first need to put the core dump
from stdin onto the disk, and that's precisely the bit that we are
doing now (and not much more) and which takes so long. We also
compress it along the way of course, mostly because we don't have much
choice. Uncompressed core dumps are huuuge, and writing them to things
like slow and small MMC cards/phone memory wouldn't help in the
slightest.
Steve Langasek [2015-10-22 18:11 -0000]:
> > * If we really want to dump, we could investigate into sendfile. I'm not
> > * entirely sure that it works with data coming in via stdin, but it's
> > * worth a try as we would avoid the kernel -> userspace copy.
>
> This is an interesting suggestion. It would imply requiring a second
> post-processing stage, to combine this file with the rest of the crash
> report in proper (compressed, base64-encoded) format;
How would that help? In any case you first need to put the core dump
from stdin onto the disk, and that's precisely the bit that we are
doing now (and not much more) and which takes so long. We also
compress it along the way of course, mostly because we don't have much
choice. Uncompressed core dumps are huuuge, and writing them to things
like slow and small MMC cards/phone memory wouldn't help in the
slightest.