Re: [PATCH v5 01/12] pkt-line: eliminate the need for static buffer in packet_write_gently()

> "Jeff Hostetler via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
> > +	/*
> > +	 * Write the header and the buffer in 2 parts so that we do not need
> > +	 * to allocate a buffer or rely on a static buffer.  This avoids perf
> > +	 * and multi-threading issues.
> > +	 */
> 
> I understand "multi-threading issues" (i.e. let's not have too much
> stuff on the stack), but what issue around "perf" are we worried
> about?
> 
> Even though we eliminate memcpy() from the original buffer to our
> temporary, this doubles the number of write(2) system calls used to
> write out packetised data, by the way.  I do not know if this results
> in measurable performance degradation, but hopefully we can fix it
> locally if it turns out to be a real problem later.