On Linux and Android arm64, we use LUL for stackwalking. LUL's initialization takes a very long time. This manifests in the following ways: - Manually starting the profiler for the first time causes the browser to be unresponsive for a short time. - Content processes that start up during profiling are delayed. This is more serious with Fission. - It's most serious when profiling startup: During startup, many processes are launched, and each of them hits the startup overhead: parent, GPU, network, add-ons, content. With multiple processes interacting, this delay distorts the profiles; we're now profiling an unrealistic scenario. Let's use this bug as a meta bug and file individual bugs for specific mitigations of this problem.
Bug 1635810 Comment 0 Edit History
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On Linux and Android arm64, we use LUL for stackwalking. LUL's initialization takes a very long time. This manifests in the following ways: - Manually starting the profiler for the first time causes the browser to be unresponsive for a short time. - Content processes that start up during profiling are delayed. This is more serious with Fission. - It's most serious when profiling Firefox startup: During startup, many processes are launched, and each of them hits the initialization overhead: parent, GPU, network, add-ons, content. With multiple processes interacting, this delay distorts the profiles; we're now profiling an unrealistic scenario. Let's use this bug as a meta bug and file individual bugs for specific mitigations of this problem.