Date: Tue, 6 Nov 2018 13:48:12 +0100 From: Stefan Esser <se@freebsd.org> To: Steevan Rodrigues <steevanxperia@gmail.com>, mad@madpilot.net Cc: freebsd-hackers@freebsd.org, vhaisman@gmail.com Subject: Re: FreeBSD 11.x thread creation time is 9000+ microseconds on Intel Xeon Gold series CPU Message-ID: <0f7e583f-9ad9-f210-4bdb-1ace13ab8c5f@freebsd.org> In-Reply-To: <CAKsGTHRUUxW0Ww-0HXKN-S-r9V5Sj1ZU%2BDgdQ1ObHg75RkGxCQ@mail.gmail.com> References: <CAKsGTHQnaEsqmf_g%2BhH=agmfJ5Z4sZY8qkw1iJWyOF=1e6qm-g@mail.gmail.com> <7bb8463e-aa5d-bade-7ae7-6c612bae65f9@gmail.com> <CAKsGTHTLAaPW6P94J_uv%2ByPpOv9FuZZQQjBDYV-vTJUDYZSa%2Bg@mail.gmail.com> <e5333ed8-9788-41e0-5c75-c72af1525029@madpilot.net> <CAKsGTHRUUxW0Ww-0HXKN-S-r9V5Sj1ZU%2BDgdQ1ObHg75RkGxCQ@mail.gmail.com>
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Am 06.11.18 um 12:05 schrieb Steevan Rodrigues: > Thanks to all of you for the quick responses. > > I see this issue only on a particular server. > I do not see this issue on another server with slightly older processor > Intel(R) Xeon(R) CPU E5-2620 v2 @ 2.10GHz (dual socket 6 core per socket) > In this system the same program takes only about 800 usec > > I wonder whether it is problem with 11.x FreeBSD release on this particular > processor. > I came across two results (given below) from Phoronix OSbench test suite > which also show poor thread creation time for FreeBSD 11.x > > https://openbenchmarking.org/result/1804094-AR-1804096AR58 > https://openbenchmarking.org/result/1807114-RA-WINDOWSSE47 > > In this look for "Create Threads" row. This list shows, that FreeBSD-12 is fast, only FreeBSD-11 shows the long thread creation time (16000 vs 36 in whatever units), even though FreeBSD-12 was running with KPTI-Patches. This lets me think that the issue that caused these delays has been fixed, but not merged to FreeBSD-11, yet.# I guess that the cause for the delays is the synchronization IPIs between sockets, and that these might be very high due to some cores in deep sleep modes (with corresponding long wake-up delays). Regards, STefan
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