08/11/2024 20:53, Morten Brørup: > > From: Morten Brørup [mailto:m...@smartsharesystems.com] > > Sent: Friday, 8 November 2024 19.35 > > > > > From: David Marchand [mailto:david.march...@redhat.com] > > > Sent: Friday, 8 November 2024 19.18 > > > > > > OVS locks all pages to avoid page faults while processing packets. > > It sounds smart, so I just took a look at how it does this. I'm not sure, but > it seems like it only locks pages that are actually mapped (current and > future). > > > > 1M for each lcore translates to allocating 128M with default build > > > options on x86. > > > This resulted in OOM while running unit tests in parallel. > > Is the root cause the lcore variables library itself, or the unit test using > a lot of memory for testing the lcore variables? > We don't want to fix the library if the problem is elsewhere.
The fix works for our urgent issue and we want to make a release candidate soon. > > > At the moment, the more demanding DPDK user of lcore variable is > > > rte_service, with a 2112 bytes object. > > > > > > Limit the lcore variable maximum size to 4k which looks more > > > reasonable. > > > > 4 KB is not future proof. > > > > Here's an example where 16 KB is cutting it close: > > https://inbox.dpdk.org/dev/98CBD80474FA8B44BF855DF32C47DC35E9F7D0@smart > > server.smartshare.dk/ > > > > Depends on how we are going to use it. 4 KB suffices if we only want to > > use it for "small" structures. This is what is stated in the doc: "Lcore variables are suitable for small objects" "The amount of data kept in lcore variables is projected to be small" > > Would 64 KB work as a compromise? Let's consider based on the need. The lcore variables are new and we don't want it to degrade the DPDK footprint, at least not in this first version. 4 KB is a memory page on common systems, it looks reasonnable and big enough for a "variable". Applied, thanks.
