From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: "Mathias Nyman" <mathias.nyman@linux.intel.com>,
"Łukasz Bartosik" <ukaszb@chromium.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Sasha Levin" <sashal@kernel.org>
Subject: [PATCH 5.15.y 4/6] xhci: dbc: Improve performance by removing delay in transfer event polling.
Date: Mon, 27 Oct 2025 14:42:50 -0400 [thread overview]
Message-ID: <20251027184252.639069-4-sashal@kernel.org> (raw)
In-Reply-To: <20251027184252.639069-1-sashal@kernel.org>
From: Mathias Nyman <mathias.nyman@linux.intel.com>
[ Upstream commit 03e3d9c2bd85cda941b3cf78e895c1498ac05c5f ]
Queue event polling work with 0 delay in case there are pending transfers
queued up. This is part 2 of a 3 part series that roughly triples dbc
performace when using adb push and pull over dbc.
Max/min push rate after patches is 210/118 MB/s, pull rate 171/133 MB/s,
tested with large files (300MB-9GB) by Łukasz Bartosik
First performance improvement patch was commit 31128e7492dc
("xhci: dbc: add dbgtty request to end of list once it completes")
Cc: Łukasz Bartosik <ukaszb@chromium.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20241227120142.1035206-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: f3d12ec847b9 ("xhci: dbc: fix bogus 1024 byte prefix if ttyDBC read races with stall event")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/host/xhci-dbgcap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
index 004e69f424860..ce56b9316e124 100644
--- a/drivers/usb/host/xhci-dbgcap.c
+++ b/drivers/usb/host/xhci-dbgcap.c
@@ -987,7 +987,7 @@ static void xhci_dbc_handle_events(struct work_struct *work)
/* set fast poll rate if there are pending data transfers */
if (!list_empty(&dbc->eps[BULK_OUT].list_pending) ||
!list_empty(&dbc->eps[BULK_IN].list_pending))
- poll_interval = 1;
+ poll_interval = 0;
break;
default:
dev_info(dbc->dev, "stop handling dbc events\n");
--
2.51.0
next prev parent reply other threads:[~2025-10-27 18:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-27 7:20 FAILED: patch "[PATCH] xhci: dbc: fix bogus 1024 byte prefix if ttyDBC read races" failed to apply to 5.15-stable tree gregkh
2025-10-27 18:42 ` [PATCH 5.15.y 1/6] xhci: dbc: Provide sysfs option to configure dbc descriptors Sasha Levin
2025-10-27 18:42 ` [PATCH 5.15.y 2/6] xhci: dbc: poll at different rate depending on data transfer activity Sasha Levin
2025-10-27 18:42 ` [PATCH 5.15.y 3/6] xhci: dbc: Allow users to modify DbC poll interval via sysfs Sasha Levin
2025-10-27 18:42 ` Sasha Levin [this message]
2025-10-27 18:42 ` [PATCH 5.15.y 5/6] xhci: dbc: Avoid event polling busyloop if pending rx transfers are inactive Sasha Levin
2025-10-27 18:42 ` [PATCH 5.15.y 6/6] xhci: dbc: fix bogus 1024 byte prefix if ttyDBC read races with stall event Sasha Levin
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