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t=1684131228; bh=Y45E+N01pMi2CMlWB0B+OganKrfzdE6yeEf0dWAO4yU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=R3Y89wxdF1A1pzNHqxrT7L4mihy9RdQllcqFtvj2Ja+ux0lx5o9lynlUAuoHXNvA3 wx9hwEOsJFlXM3ec3IRUpAat/xUwFv8w7TJPO2FPZI0xYfXnIwG2mjgpArZIx+Cf4u sZ3ZuILtK0r7DXqsvUsNH2lSLDipgk5anqaV/yljSxXaVSySMpLeL+BQC44hBnoqmD pcH/qj625BS6iurlQoDR/YMyW5D+3qi9RpSjSBs3R/Xw6jh7zN3PDw5h6zzwhz8b4p VEQ1t7MDdFQT8RxLIOHY2kRuoOX9DfhQjxUnT9yxY74Ovoc9/tWJC0BCHf1vKDW3Ts 2/xioqiq8OsAg== Date: Sun, 14 May 2023 23:13:46 -0700 From: Eric Biggers To: Kent Overstreet Cc: Lorenzo Stoakes , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-bcachefs@vger.kernel.org, Kent Overstreet , Andrew Morton , Uladzislau Rezki , linux-mm@kvack.org Subject: Re: [PATCH 07/32] mm: Bring back vmalloc_exec Message-ID: <20230515061346.GB15871@sol.localdomain> References: <20230509165657.1735798-8-kent.overstreet@linux.dev> <20230510064849.GC1851@quark.localdomain> <20230513015752.GC3033@quark.localdomain> <20230514184325.GB9528@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: A15DE40009 X-Stat-Signature: 78efhu4okg9bg14t1r16ru1z57cuftut X-HE-Tag: 1684131229-100126 X-HE-Meta: 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 xqGVDcEx V+UoLMi3bep+TZoSlP/LTdt0lws3Vo3GCv2yAOYZCED0g5x08XM3+mwBLYM3sAF2VU2AHvLKgisshahrnYT9hbv+0RHcYGYwhhlor24pHhg2/AcRU8mLESUwVfl54W9zfFxkbZxEZ5XKgzy8rvH1bC6oArSbnzwNzmD2Z+d2GcqnETjEBhqnbwnl01VNKP6pJAPRdXtlSBAp3iDvZFB9+UzP1MukpDfEVpFXI7mJZarlJx20pMQVsrXfv2S/8B4I5KU04tJ3qqNoaDX26CclRAZXMVUYXcy3/aEJHwfmY7OPB2/skUXuJs5KimZM6e+gCcpH2G9hrp2khCRgZUauvRaeqJooH+CQ1cPWZnmt4oxNi0CFwHB4rHcYUQQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, May 15, 2023 at 01:38:51AM -0400, Kent Overstreet wrote: > On Sun, May 14, 2023 at 11:43:25AM -0700, Eric Biggers wrote: > > I think it would also help if the generated assembly had the handling of the > > fields interleaved. To achieve that, it might be necessary to interleave the C > > code. > > No, that has negligable effect on performance - as expected, for an out > of order processor. < 1% improvement. > > It doesn't look like this approach is going to work here. Sadly. I'd be glad to take a look at the code you actually tried. It would be helpful if you actually provided it, instead of just this "I tried it, I'm giving up now" sort of thing. I was also hoping you'd take the time to split this out into a userspace micro-benchmark program that we could quickly try different approaches on. BTW, even if people are okay with dynamic code generation (which seems unlikely?), you'll still need a C version for architectures that you haven't implemented the dynamic code generation for. - Eric