Date: Thu, 09 Nov 2023 19:25:47 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 274994] Regression of iperf3 network throughput tests with erms "rep movsb" copyto loops Message-ID: <bug-274994-227-oQ2ITgTnLp@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-274994-227@https.bugs.freebsd.org/bugzilla/> References: <bug-274994-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D274994 --- Comment #2 from Mateusz Guzik <mjg@FreeBSD.org> --- I can run FreeBSD in a vm on Intel(R) Xeon(R) Platinum 8470N which is also Sapphire Rapids. I get: [ 5] 0.00-10.00 sec 71.0 GBytes 61.0 Gbits/sec 3 sender [ 5] 0.00-10.00 sec 71.0 GBytes 61.0 Gbits/sec recei= ver Which is the as Linux on the same machine. Poor man's profiling with dtrace: dtrace -w -n 'profile:::profile-4999 { @[sym(arg0)] =3D count(); } tick-10s { system("clear"); trunc(@, 40); printa("%40a %@16d\n", @); clear(@); }' ... shows that while copyin is indeed high up in terms of CPU usage, the singular most time-consuming thing is lock contention. [snip] kernel`mb_dupcl 2172 kernel`tcp_m_copym 2279 kernel`m_getm2 2683 kernel`tcp_default_output 3364 kernel`mb_free_ext 3443 kernel`spinlock_exit 3487 kernel`tcp_do_segment 4243 kernel`soreceive_generic 5127 kernel`copyout_smap_erms 9601 kernel`copyin_smap_erms 9744 kernel`lock_delay 12566 kernel`acpi_cpu_c1 719581 --=20 You are receiving this mail because: You are the assignee for the bug.=
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