Date: Sat, 25 Mar 2023 19:58:55 +0100 From: Peter <pmc@citylink.dinoex.sub.org> To: Mark Millard <marklmi@yahoo.com> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Periodic rant about SCHED_ULE Message-ID: <ZB9Ebx2/Eo/GQzDl@disp.intra.daemon.contact> In-Reply-To: <5AF26266-5B4C-4A7F-8784-4C6308B6C5CA@yahoo.com> References: <5AF26266-5B4C-4A7F-8784-4C6308B6C5CA.ref@yahoo.com> <5AF26266-5B4C-4A7F-8784-4C6308B6C5CA@yahoo.com>
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On Sat, Mar 25, 2023 at 11:14:11AM -0700, Mark Millard wrote: ! Why did PID 10675 change to 19028? Because it went into some NFS share, and it would still be there if I hadn't restartet it a bit differently. ! When I tried that tar line, I get lots of output to stderr: ! ! # tar cvf - / | cpuset -l 13 gzip -9 > /dev/null ! tar: Removing leading '/' from member names ! a . ! a root ! a wrkdirs ! a bin ! a usr ! . . . ! ! Was that an intentional part of the test? Yes. So you can see what it is currently feeding to gzip (small or big files - or some NFS share, where the operation becomes pointless). ! # tar cvf - / 2>/dev/null | cpuset -l 13 gzip -9 2>&1 > /dev/null ! ! At which point I get the likes of: ! ! 17129 root 1 68 0 14192Ki 3628Ki RUN 13 0:20 3.95% gzip -9 ! 17128 root 1 20 0 58300Ki 13880Ki pipdwt 18 0:00 0.27% tar cvf - / (bsdtar) ! 17097 root 1 133 0 13364Ki 3060Ki CPU13 13 8:05 95.93% sh -c while true; do :; done ! ! up front. Ah. So? To me this doesn't look good. If both jobs are runnable, they should each get ~50%. ! For reference, I also see the likes of the following from ! "gstat -spod" (it is a root on ZFS context with PCIe Optane media): So we might assume that indeed both jobs are runable, and the only significant difference is that one does system calls while the other doesn't. The point of this all is: identify the malfunction with the most simple usecase. (And for me here is a malfunction.) And then, obviousely, fix it.
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