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

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 11, 2021, 20:32 UTC
Message-ID: <xmqq4khhctya.fsf@gitster.g>
In-Reply-To: <YEpvfztZWhAvSDTL@coredump.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 18 quoted lines

> On Tue, Mar 09, 2021 at 03:48:40PM -0800, Junio C Hamano wrote:
>
>> "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?
>>  ...
> Yeah, this came from my suggestion. My gut feeling is that it isn't
> likely to matter, but I'd much rather solve any performance problem we
> find using writev(), which would be pretty easy to emulate with a
> wrapper for systems that lack it.

I too had writev() in mind when I said "can fix it locally", so we are on the same page, which is good.

So "this avoid multi-threading issues" without mentioning "perf and" would be more appropriate?

Thanks.