{"id":2197765,"url":"http://patchwork.ozlabs.org/api/1.0/patches/2197765/?format=json","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.0/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260218132633.29748-24-hreitz@redhat.com>","date":"2026-02-18T13:26:32","name":"[v4,23/24] qapi/block-export: Document FUSE's multi-threading","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"3cf34662520b3900a8682852dc478d297f7ef79b","submitter":{"id":82279,"url":"http://patchwork.ozlabs.org/api/1.0/people/82279/?format=json","name":"Hanna Czenczek","email":"hreitz@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260218132633.29748-24-hreitz@redhat.com/mbox/","series":[{"id":492547,"url":"http://patchwork.ozlabs.org/api/1.0/series/492547/?format=json","date":"2026-02-18T13:26:09","name":"export/fuse: Use coroutines and multi-threading","version":4,"mbox":"http://patchwork.ozlabs.org/series/492547/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2197765/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=Kl8V4gA4;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=google header.b=gGiBSUPa;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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charset=UTF-8","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.043,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001,\n SPF_HELO_PASS=-0.001,\n SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Document for users that FUSE's multi-threading implementation\ndistributes requests in a round-robin manner, regardless of where they\noriginate from.\n\nAs noted by Stefan, this will probably change with a FUSE-over-io_uring\nimplementation (which is supposed to have CPU affinity), but documenting\nthat is left for once that is done.\n\nSuggested-by: Stefan Hajnoczi \nAcked-by: Markus Armbruster \nSigned-off-by: Hanna Czenczek \n---\n qapi/block-export.json | 5 +++++\n 1 file changed, 5 insertions(+)","diff":"diff --git a/qapi/block-export.json b/qapi/block-export.json\nindex 160cd2e3ca..dd724acf1c 100644\n--- a/qapi/block-export.json\n+++ b/qapi/block-export.json\n@@ -164,6 +164,11 @@\n # Options for exporting a block graph node on some (file) mountpoint\n # as a raw image.\n #\n+# Multi-threading note: The FUSE export supports multi-threading.\n+# Currently, requests are distributed across these threads in a\n+# round-robin fashion, i.e. independently of the CPU core from which a\n+# request originates.\n+#\n # @mountpoint: Path on which to export the block device via FUSE.\n # This must point to an existing regular file.\n #\n","prefixes":["v4","23/24"]}