[arch-general] IPC slowness

[David C. Rankin]

On 03/07/2019 03:51 PM, frederik at ofb.net wrote:
> Any ideas what might be causing this? I tried to debug with 'strace -r
> -p' and it looks like most of the time is getting spent in a 'select'
> call.
> 
>     0.000171 geteuid()                 = 1000
>     0.000075 getegid()                 = 1000
>     0.000080 select(1024, [3 4 5 6], [], NULL, NULL) = 1 (in [3])
>     0.399534 fcntl(3, F_SETFL, O_RDONLY) = 0
>     0.000171 read(3, "\0gsm\4\0\0\0/dev/pts/33\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 12336) = 12336
>     0.000169 close(3)                  = 0

Are you using Arch on bare-metal or in VirtualBox 6.x by chance? I saw similar
slowdowns with VirtualBox 6.0 (and 6.2) when run --headless and similar strace
errors (although with poll/write), e.g.

[pid 32452] poll([{fd=3, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=3,
revents=POLLOUT}])
[pid 32452] writev(3, [{iov_base="b\0\4\0\6\0@\4", iov_len=8},
{iov_base="RENDER", iov_len=6}, {iov_base="\0\0", io
v_len=2}], 3) = 16
[pid 32452] futex(0x7fffd1f3f468, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
[pid 32493] +++ killed by SIGABRT (core dumped) +++


-- 
David C. Rankin, J.D.,P.E.