Date: Fri, 03 Aug 2018 16:25:03 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230334] busdma(9) is missing bus_dmamap_sync_range() Message-ID: <bug-230334-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D230334 Bug ID: 230334 Summary: busdma(9) is missing bus_dmamap_sync_range() Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: jhibbits@FreeBSD.org bus_dmamap_sync(9) syncs the entire page range in a mapping, which can be v= ery costly if only a small range is needed. Some drivers, perhaps many, share DMA maps for multiple queues or entries, = and only need to update one segment. Instead of syncing the full map, there sh= ould be a way to sync only the updated range. This is mentioned in https://reviews.freebsd.org/D16570 regarding NVMe performance implications, and in https://reviews.freebsd.org/D16517 as miss= ing for sound buffers. --=20 You are receiving this mail because: You are the assignee for the bug.=
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