Re: [PATCH v2 2/2] virtio-ring: Allocate indirect buffers from cache when possible
From: Sasha Levin <hidden>
Date: 2012-08-29 16:52:37
Also in:
kvm, virtualization
On 08/29/2012 05:38 PM, Michael S. Tsirkin wrote:
On Wed, Aug 29, 2012 at 05:03:03PM +0200, Sasha Levin wrote:quoted
On 08/29/2012 01:07 PM, Michael S. Tsirkin wrote:quoted
On Tue, Aug 28, 2012 at 03:35:00PM +0200, Sasha Levin wrote:quoted
On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote:quoted
On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote:quoted
Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will use indirect descriptors and allocate them using a simple kmalloc(). This patch adds a cache which will allow indirect buffers under a configurable size to be allocated from that cache instead. Signed-off-by: Sasha Levin <redacted>I imagine this helps performance? Any numbers?I ran benchmarks on the original RFC, I've re-tested it now and got similar numbers to the original ones (virtio-net using vhost-net, thresh=16): Before: Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 4512.12 After: Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 5399.18 Thanks, SashaThis is with both patches 1 + 2? Sorry could you please also test what happens if you apply - just patch 1 - just patch 2 Thanks!Sure thing! I've also re-ran it on a IBM server type host instead of my laptop. Here are the results: Vanilla kernel: MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 () port 0 AF_INET enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 7922.72 Patch 1, with threshold=16: MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 () port 0 AF_INET enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 8415.07 Patch 2: MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 () port 0 AF_INET enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 8931.05 Note that these are simple tests with netperf listening on one end and a simple 'netperf -H [host]' within the guest. If there are other tests which may be interesting please let me know. Thanks, SashaAnd which parameter did you use for patch 2?
Same as in the first one, 16, the only difference in patch 2 is that we use a kmemcache, so there's no point in changing the threshold vs patch 1. Thanks, Sasha