From mboxrd@z Thu Jan 1 00:00:00 1970 From: frank.blaschka@de.ibm.com Subject: [patch 6/6] [PATCH] qeth: Fix HiperSockets performance regression Date: Mon, 21 Jan 2013 13:30:23 +0100 Message-ID: <20130121123037.755818924@de.ibm.com> References: <20130121123017.240686588@de.ibm.com> Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, Stefan Raspl To: davem@davemloft.net Return-path: Received: from e06smtp15.uk.ibm.com ([195.75.94.111]:44259 "EHLO e06smtp15.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753577Ab3AUMam (ORCPT ); Mon, 21 Jan 2013 07:30:42 -0500 Received: from /spool/local by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 21 Jan 2013 12:29:34 -0000 Content-Disposition: inline; filename=605-qeth-hipersocket-performance.diff Sender: netdev-owner@vger.kernel.org List-ID: From: Stefan Raspl Commit 46d3ceab "tcp: TCP Small Queues" has severly degraded performance for single connection RR workloads on HiperSockets with MTU >=16K due to a conflict of the TCP Small Queues approach with our buffer scan threshold which releases buffers not frequently enough yet. This fix restores performance to the same level as before cited commit. Signed-off-by: Stefan Raspl Signed-off-by: Frank Blaschka --- drivers/s390/net/qeth_core_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -4700,7 +4700,7 @@ static int qeth_qdio_establish(struct qe init_data.output_sbal_addr_array = (void **) out_sbal_ptrs; init_data.output_sbal_state_array = card->qdio.out_bufstates; init_data.scan_threshold = - (card->info.type == QETH_CARD_TYPE_IQD) ? 8 : 32; + (card->info.type == QETH_CARD_TYPE_IQD) ? 1 : 32; if (atomic_cmpxchg(&card->qdio.state, QETH_QDIO_ALLOCATED, QETH_QDIO_ESTABLISHED) == QETH_QDIO_ALLOCATED) {