xmodmap really slow

[Alan Hourihane]

On 30/07/18 22:00, Adam Jackson wrote:
> On Thu, 2018-07-26 at 12:25 +0100, Alan Hourihane wrote:
>> Anyone tried just doing this recently....
>>
>> xmodmap -pke > /tmp/keydump
>> xmodmap /tmp/keydump
>>
>> And watch the Xserver hang for quite some time.
> Seems to be nearly instantaneous against an Xvfb, but did cause a
> noticable hiccup with Xorg. Haven't investigated more closely, so I'd
> suspect (in rough order of likelihood):
>
> a) something super-linear in the number of input devices
> b) some weird slow ioctl syncing the X state to the kernel
> c) somehow you end up on the "lets spawn xkbcomp" path and the
> fork/exec overhead kills you
>

Definitely not the last, moving "xkbcomp" from /usr/bin results in the
same issue.

Alan.