Re: Support for SIGSTOP/SIGCONT in nice?

[Simon Josefsson]

Jim Meyering <address@hidden> writes:

> Simon Josefsson <address@hidden> wrote:
> ...
>> Frequently when I want to run a long-running I/O-bound job (i.e.,
>> rsync of the entire disk to a second disk) on a busy machine (i.e.,
>> mail and web server), the load increases to ~10 from a normal <1.
>> Using 'nice' doesn't help.  I don't know why this is, but I suspect
>> the kernel scheduler is sub-optimal for disk-bound jobs.
>>
>> Would it be useful to consider extending nice so it can send SIGSTOP
>> and SIGCONT signals in configurable intervals?  Having rsync run for
>> 30 seconds, sleep for 15, run for 30 seconds, etc, seem to avoid
>> slowing down the system to unusable levels.
>
> Hi Simon,
>
> Have you already tried using rsync's existing option to limit bandwidth?
>
>   rsync --bwlimit=500 ...

Hi Jim!  I had forgotten about it.  It seem to have solved the actual
problem I had.

Still, maybe not all programs have similar rate-limiting features, so
that this nice-extension may be useful anyway...

Thanks,
Simon