Date: Thu, 20 Dec 2012 00:35:17 +0800 From: Julian Elischer <julian@freebsd.org> To: mjacob@freebsd.org Cc: freebsd-arch@freebsd.org Subject: Re: Unmapped I/O Message-ID: <50D1ECC5.2070209@freebsd.org> In-Reply-To: <50D1D2BD.80107@freebsd.org> References: <20121219135451.GU71906@kib.kiev.ua> <50D1D2BD.80107@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 12/19/12 10:44 PM, Matthew Jacob wrote: > On 12/19/2012 5:54 AM, Konstantin Belousov wrote: >> One of the known FreeBSD I/O path performance bootleneck is the >> neccessity to map each I/O buffer pages into KVA. The problem is that >> on the multi-core machines, the mapping must flush TLB on all cores, >> due to the global mapping of the buffer pages into the kernel. This >> means that buffer creation and destruction disrupts execution of all >> other cores to perform TLB shootdown through IPI, and the thread >> initiating the shootdown must wait for all other cores to execute and >> report. >> > About time! yeah.. Bill Jolitz had patches for this in 92 ... that disappeared with him. > _______________________________________________ > freebsd-arch@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org" > >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?50D1ECC5.2070209>