Staging
v0.6.0
v0.6.0
Revision a0783cd0c810504427777e8aae20d5f4f8b652a0 authored by Corinna Vinschen on 19 November 2019, 09:09:39 UTC, committed by David S. Miller on 20 November 2019, 00:41:11 UTC
During performance testing, I found that one of my r8169 NICs suffered a major performance loss, a 8168c model. Running netperf's TCP_STREAM test didn't return the expected throughput of > 900 Mb/s, but rather only about 22 Mb/s. Strange enough, running the TCP_MAERTS and UDP_STREAM tests all returned with throughput > 900 Mb/s, as did TCP_STREAM with the other r8169 NICs I can test (either one of 8169s, 8168e, 8168f). Bisecting turned up commit 93681cd7d94f83903cb3f0f95433d10c28a7e9a5, "r8169: enable HW csum and TSO" as the culprit. I added my 8168c version, RTL_GIGA_MAC_VER_22, to the code special-casing the 8168evl as per the patch below. This fixed the performance problem for me. Fixes: 93681cd7d94f ("r8169: enable HW csum and TSO") Signed-off-by: Corinna Vinschen <vinschen@redhat.com> Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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lshrdi3.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* lib/lshrdi3.c
*/
#include <linux/module.h>
#include <linux/libgcc.h>
long long notrace __lshrdi3(long long u, word_type b)
{
DWunion uu, w;
word_type bm;
if (b == 0)
return u;
uu.ll = u;
bm = 32 - b;
if (bm <= 0) {
w.s.high = 0;
w.s.low = (unsigned int) uu.s.high >> -bm;
} else {
const unsigned int carries = (unsigned int) uu.s.high << bm;
w.s.high = (unsigned int) uu.s.high >> b;
w.s.low = ((unsigned int) uu.s.low >> b) | carries;
}
return w.ll;
}
EXPORT_SYMBOL(__lshrdi3);
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