On Tue, Jul 2, 2024 at 11:11 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > On Tue, Jul 02, 2024 at 08:35:08PM -0700, Andrii Nakryiko wrote: > > On Tue, Jul 2, 2024 at 6:11 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > > On Tue, Jul 02, 2024 at 05:06:14PM -0700, Andrii Nakryiko wrote: > > > > In general, even with false positives, I think it's overwhelmingly > > > > better to get correct entry stack trace 99.9% of the time, and in the > > > > rest 0.01% cases it's fine having one extra bogus entry (but the rest > > > > should still be correct), which should be easy for humans to recognize > > > > and filter out, if necessary. > > > > > > Agreed, this is a definite improvement overall. > > > > Cool, I'll incorporate that into v3 and send it soon. > > BTW, if you have a chance, please do take a look at v3 and leave your ack, if you are ok with it. Thanks! > > > > > > BTW, soon there will be support for sframes instead of frame pointers, > > > at which point these checks should only be done for the frame pointer > > > case. > > > > Nice, this is one of the reasons I've been thinking about asynchronous > > stack trace capture in BPF (see [0] from recent LSF/MM). > > [0] https://docs.google.com/presentation/d/1k10-HtK7pP5CMMa86dDCdLW55fHOut4co3Zs5akk0t4 > > I don't seem to have permission to open it. > Argh, sorry, it's under my corporate account which doesn't allow others to view it. Try this, I "published" it, let me know if that still doesn't work: [0] https://docs.google.com/presentation/d/e/2PACX-1vRgL3UPbkrznwtNPKn-sSjvan7tFeMqOrIyZAFSSEPYiWG20JGSP80jBmZqGwqMuBGVmv9vyLU4KRTx/pub > > Few questions, while we are at it. Does it mean that > > perf_callchain_user() will support working from sleepable context and > > will wait for data to be paged in? Is anyone already working on this? > > Any pointers? > > I had a prototype here: > > https://lkml.kernel.org/lkml/cover.1699487758.git.jpoimboe@xxxxxxxxxx > > Hopefully I can get started on v2 soon. Ok, so you are going to work on this. Please cc me on future revisions then. Thanks! > > -- > Josh
