On Mon, 21 Jun 2021 05:49:28 +0000
Viet-Duc Le wrote:
> Hi,
>
> I've encountered a peculiar issue with rxvt-unicode launched from
> xwin-xdg-menu (20170321-1)
> The image below corresponds to two rxvt-unicode instances, each occupies 30%
> of system resouce.
> https://imgur.com/a/FTFwIrZ
> I'm using the the latest version of cygwin. 'cygcheck.out' is attached per
> guideline.
>
> Steps to reproduce:
> - Start XWin Server from Start menu
> - X applications menu -> System Tools -> rxvt-unicode
> - Kill rxvt-unicode to free the resource again
>
> Other observations:
> - XTerm does not incur high resources.
> - Manually launching rxvt-unicode from XTerm does not incur high resources.
>
> I think this is not an issue with rxvt but with xwin-xdg-menu.
> On laptop, it is very noticeable when the fan kicks in.
> Insights and suggestions are much appreciated.
>
> Thanks.
> Viet-Duc
I looked into this problem and found the cause.
urxvt seems to close stdout while xwin-xdg-menu use select()
to read stdout of the launched apps. Since stdout is closed,
select() returns repeatedly without any output. This causes
high cpu load.
I also confirmed that the following patch for xwin-xdg-menu
resolves the issue.
--- execute.c.orig 2017-03-22 05:31:53.000000000 +0900
+++ execute.c 2021-06-22 10:47:28.917675400 +0900
@@ -100,30 +100,38 @@
default: /* parent */
{
+ int stdout_ok = TRUE, stderr_ok = TRUE;
close(stdout_filedes[1]);
close(stderr_filedes[1]);
printf("executing '%s', pid %d\n", (char *) cmd, pid);
/* read from pipes, write to log, until both are closed */
- while (TRUE) {
+ while (stdout_ok || stderr_ok) {
fd_set readfds, errorfds;
- int nfds = max(stdout_filedes[0], stderr_filedes[0]) + 1;
+ int nfds = 0;
FD_ZERO(&readfds);
- FD_SET(stdout_filedes[0], &readfds);
- FD_SET(stderr_filedes[0], &readfds);
+ if (stdout_ok) {
+ FD_SET(stdout_filedes[0], &readfds);
+ nfds = max(nfds, stdout_filedes[0] + 1);
+ }
+ if (stderr_ok) {
+ FD_SET(stderr_filedes[0], &readfds);
+ nfds = max(nfds, stderr_filedes[0] + 1);
+ }
errorfds = readfds;
if (select(nfds, &readfds, NULL, &errorfds, NULL) > 0) {
- if (FD_ISSET(stdout_filedes[0], &readfds))
+ if (FD_ISSET(stdout_filedes[0], &errorfds))
+ stdout_ok = FALSE;
+ else if (FD_ISSET(stdout_filedes[0], &readfds))
LogLineFromFd(stdout_filedes[0], "stdout", pid);
- if (FD_ISSET(stderr_filedes[0], &readfds))
- LogLineFromFd(stderr_filedes[0], "stderr", pid);
- if (FD_ISSET(stdout_filedes[0], &errorfds) &&
- FD_ISSET(stderr_filedes[0], &errorfds))
- break;
+ if (FD_ISSET(stderr_filedes[0], &errorfds))
+ stderr_ok = FALSE;
+ else if (FD_ISSET(stderr_filedes[0], &readfds))
+ LogLineFromFd(stderr_filedes[0], "stderr", pid);
}
else {
break;
Jon, could you please have a look?
--
Takashi Yano <takashi.y...@nifty.ne.jp>
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